Related
Im new to Razor and View Models and I just want to ask if its possible to Display different string in [Display(Name = "")]
I tried adding condition in between the Display and the variable but it shows error
also tried this
public string Color {get;set;}
public String ColorDisplay
{
get
{
String name = "";
if (ColorId == 25 || ColorId == 26)
{
name = "Purple";
}
else
{
name = "Green";
}
return name;
}
}
Then in my View
#Html.LabelFor(m => m.ColorDisplay)
but seems not working as it just dispay ColorDisplay
In this issue, probably you may need a custom attribute to change text based on provided values inside attribute properties. Assumed that you want custom attribute usage like this:
[DisplayWhen("ColorId", 25, 26, "Purple", "Green")]
public String Color { get; set; }
And using HTML helper like this:
#Html.LabelFor(m => m.Color)
Then you should do these steps:
1) Create a custom attribute inherited from Attribute class.
public class DisplayWhenAttribute : Attribute
{
private string _propertyName;
private int _condition1;
private int _condition2;
private string _trueValue;
private string _falseValue;
public string PropertyName
{
get
{
return _propertyName;
}
}
public int Condition1
{
get
{
return _condition1;
}
}
public int Condition2
{
get
{
return _condition2;
}
}
public string TrueValue
{
get
{
return _trueValue;
}
}
public string FalseValue
{
get
{
return _falseValue;
}
}
public DisplayWhenAttribute(string propertyName, int condition1, int condition2, string trueValue, string falseValue)
{
_propertyName = propertyName;
_condition1 = condition1;
_condition2 = condition2;
_trueValue = trueValue;
_falseValue = falseValue;
}
}
2) Create custom metadata provider class which checks existence of custom attribute.
public class CustomModelMetadataProvider : DataAnnotationsModelMetadataProvider
{
protected override ModelMetadata CreateMetadata(IEnumerable<Attribute> attributes, Type containerType, Func<object> modelAccessor, Type modelType, string propertyName)
{
var metadata = base.CreateMetadata(attributes, containerType, modelAccessor, modelType, propertyName);
var additionalAttribute = attributes.OfType<DisplayWhenAttribute>().FirstOrDefault();
if (additionalAttribute != null)
{
metadata.AdditionalValues.Add("DisplayWhenAttribute", additionalValues);
}
return metadata;
}
}
3) Register CustomModelMetadataProvider into Application_Start() method inside Global.asax like this:
protected void Application_Start()
{
ModelMetadataProviders.Current = new CustomModelMetadataProvider();
}
4) Create your own (or override existing) LabelFor helper so that it checks against DisplayWhenAttribute, as in example below:
public static MvcHtmlString LabelFor<TModel, TProperty>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression, IDictionary<string, object> htmlAttributes)
{
string result = string.Empty;
var modelMetaData = expression.Compile().Invoke(helper.ViewData.Model);
string fieldName = ExpressionHelper.GetExpressionText(expression);
var containerType = typeof(TModel);
var containerProperties = containerType.GetProperties();
var propertyInfo = containerProperties.SingleOrDefault(x => x.Name == modelMetaData.PropertyName);
var attribute = propertyInfo.GetCustomAttributes(false).SingleOrDefault(x => x is DisplayWhenAttribute) as DisplayWhenAttribute;
var target = attribute.PropertyName; // target property name, e.g. ColorId
var condition1 = attribute.Condition1; // first value to check
var condition2 = attribute.Condition2; // second value to check
var targetValue = (int)containerType.GetProperty(target).GetValue(helper.ViewData.Model);
// checking provided values from attribute
if (targetValue == condition1 || targetValue == condition2)
{
result = attribute.TrueValue;
}
else
{
result = attribute.FalseValue;
}
// create <label> tag with specified true/false value
TagBuilder tag = new TagBuilder("label");
tag.MergeAttributes(htmlAttributes);
tag.Attributes.Add("for", helper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldId(fieldName));
tag.SetInnerText(result);
return MvcHtmlString.Create(tag.ToString(TagRenderMode.Normal));
}
Some references to consider with:
Is it possible to create conditional attribute as DisplayIf?
How to extend MVC3 Label and LabelFor HTML helpers?
MVC custom display attribute
I've got a property in my model called Promotion that its type is a flag enum called UserPromotion. Members of my enum have display attributes set as follows:
[Flags]
public enum UserPromotion
{
None = 0x0,
[Display(Name = "Send Job Offers By Mail")]
SendJobOffersByMail = 0x1,
[Display(Name = "Send Job Offers By Sms")]
SendJobOffersBySms = 0x2,
[Display(Name = "Send Other Stuff By Sms")]
SendPromotionalBySms = 0x4,
[Display(Name = "Send Other Stuff By Mail")]
SendPromotionalByMail = 0x8
}
Now I want to be able to create say a ul in my view to show the selected values of my Promotion property. This is what I have done so far but the problem is that how can I get the display names here?
<ul>
#foreach (int aPromotion in #Enum.GetValues(typeof(UserPromotion)))
{
var currentPromotion = (int)Model.JobSeeker.Promotion;
if ((currentPromotion & aPromotion) == aPromotion)
{
<li>Here I don't know how to get the display attribute of "currentPromotion".</li>
}
}
</ul>
One liner - Fluent syntax
public static class Extensions
{
/// <summary>
/// A generic extension method that aids in reflecting
/// and retrieving any attribute that is applied to an `Enum`.
/// </summary>
public static TAttribute GetAttribute<TAttribute>(this Enum enumValue)
where TAttribute : Attribute
{
return enumValue.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<TAttribute>();
}
}
Example
public enum Season
{
[Display(Name = "It's autumn")]
Autumn,
[Display(Name = "It's winter")]
Winter,
[Display(Name = "It's spring")]
Spring,
[Display(Name = "It's summer")]
Summer
}
public class Foo
{
public Season Season = Season.Summer;
public void DisplayName()
{
var seasonDisplayName = Season.GetAttribute<DisplayAttribute>();
Console.WriteLine("Which season is it?");
Console.WriteLine (seasonDisplayName.Name);
}
}
Output
Which season is it?
It's summer
UPDATE
First solution was focused on getting display names from enum. Code below should be exact solution for your problem.
You can use this helper class for enums:
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
public static class EnumHelper<T>
where T : struct, Enum // This constraint requires C# 7.3 or later.
{
public static IList<T> GetValues(Enum value)
{
var enumValues = new List<T>();
foreach (FieldInfo fi in value.GetType().GetFields(BindingFlags.Static | BindingFlags.Public))
{
enumValues.Add((T)Enum.Parse(value.GetType(), fi.Name, false));
}
return enumValues;
}
public static T Parse(string value)
{
return (T)Enum.Parse(typeof(T), value, true);
}
public static IList<string> GetNames(Enum value)
{
return value.GetType().GetFields(BindingFlags.Static | BindingFlags.Public).Select(fi => fi.Name).ToList();
}
public static IList<string> GetDisplayValues(Enum value)
{
return GetNames(value).Select(obj => GetDisplayValue(Parse(obj))).ToList();
}
private static string lookupResource(Type resourceManagerProvider, string resourceKey)
{
var resourceKeyProperty = resourceManagerProvider.GetProperty(resourceKey,
BindingFlags.Static | BindingFlags.Public, null, typeof(string),
new Type[0], null);
if (resourceKeyProperty != null)
{
return (string)resourceKeyProperty.GetMethod.Invoke(null, null);
}
return resourceKey; // Fallback with the key name
}
public static string GetDisplayValue(T value)
{
var fieldInfo = value.GetType().GetField(value.ToString());
var descriptionAttributes = fieldInfo.GetCustomAttributes(
typeof(DisplayAttribute), false) as DisplayAttribute[];
if (descriptionAttributes[0].ResourceType != null)
return lookupResource(descriptionAttributes[0].ResourceType, descriptionAttributes[0].Name);
if (descriptionAttributes == null) return string.Empty;
return (descriptionAttributes.Length > 0) ? descriptionAttributes[0].Name : value.ToString();
}
}
And then you can use it in your view as following:
<ul>
#foreach (var value in #EnumHelper<UserPromotion>.GetValues(UserPromotion.None))
{
if (value == Model.JobSeeker.Promotion)
{
var description = EnumHelper<UserPromotion>.GetDisplayValue(value);
<li>#Html.DisplayFor(e => description )</li>
}
}
</ul>
Building on Aydin's great answer, here's an extension method that doesn't require any type parameters.
using System;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
public static class EnumExtensions
{
public static string GetDisplayName(this Enum enumValue)
{
return enumValue.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>()
.GetName();
}
}
NOTE: GetName() should be used instead of the Name property. This ensures that the localized string will be returned if using the ResourceType attribute property.
Example
To use it, just reference the enum value in your view.
#{
UserPromotion promo = UserPromotion.SendJobOffersByMail;
}
Promotion: #promo.GetDisplayName()
Output
Promotion: Send Job Offers By Mail
Based on Aydin's answer I would suggest a less "duplicatious" implementation (because we could easily get the Type from the Enum value itself, instead of providing it as a parameter 馃槈:
using System;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
public static string GetDisplayName(this Enum enumValue)
{
return enumValue.GetType().GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>()
.Name;
}
EDIT (based upon #Vahagn Nahapetyan's comment)
public static string GetDisplayName(this Enum enumValue)
{
return enumValue.GetType()?
.GetMember(enumValue.ToString())?
.First()?
.GetCustomAttribute<DisplayAttribute>()?
.Name;
}
Now we can use it very clean in this way:
public enum Season
{
[Display(Name = "The Autumn")]
Autumn,
[Display(Name = "The Weather")]
Winter,
[Display(Name = "The Tease")]
Spring,
[Display(Name = "The Dream")]
Summer
}
Season.Summer.GetDisplayName();
Which results in
"The Dream"
If you are using MVC 5.1 or upper there is simplier and clearer way: just use data annotation (from System.ComponentModel.DataAnnotations namespace) like below:
public enum Color
{
[Display(Name = "Dark red")]
DarkRed,
[Display(Name = "Very dark red")]
VeryDarkRed,
[Display(Name = "Red or just black?")]
ReallyDarkRed
}
And in view, just put it into proper html helper:
#Html.EnumDropDownListFor(model => model.Color)
Building on Todd's great answer which built on Aydin's great answer, here's a generic extension method which doesn't require any type parameters.
/// <summary>
/// Gets human-readable version of enum.
/// </summary>
/// <returns>effective DisplayAttribute.Name of given enum.</returns>
public static string GetDisplayName<T>(this T enumValue) where T : IComparable, IFormattable, IConvertible // C# 7.3+: where T : struct, Enum
{
if (!typeof(T).IsEnum) // Not needed in C# 7.3+ with above updated constraint
throw new ArgumentException("Argument must be of type Enum");
DisplayAttribute displayAttribute = enumValue.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>();
string displayName = displayAttribute?.GetName();
return displayName ?? enumValue.ToString();
}
I needed this for my project because something like the below code, where not every member of the enum has a DisplayAttribute, throws an exception with Todd's solution:
public class MyClass
{
public enum MyEnum
{
[Display(Name="ONE")]
One,
// No DisplayAttribute
Two
}
public void UseMyEnum()
{
MyEnum foo = MyEnum.One;
MyEnum bar = MyEnum.Two;
Console.WriteLine(foo.GetDisplayName());
Console.WriteLine(bar.GetDisplayName());
}
}
// Output:
//
// ONE
// Two
If this is a complicated solution to a simple problem, please let me know, but this was the fix I used.
You could use Type.GetMember Method, then get the attribute info using reflection:
// display attribute of "currentPromotion"
var type = typeof(UserPromotion);
var memberInfo = type.GetMember(currentPromotion.ToString());
var attributes = memberInfo[0].GetCustomAttributes(typeof(DisplayAttribute), false);
var description = ((DisplayAttribute)attributes[0]).Name;
There were a few similar posts here:
Getting attributes of Enum's value
How to make MVC3 DisplayFor show the value of an Enum's Display-Attribute?
In .NET5, I used DisplayTextFor without needing helper or extension methods:
#Html.DisplayTextFor(m => m.SomeEnumProperty)
Where SomeEnumProperty has a value of:
public enum MyEnum
{
[Display(Name = "Not started")]
NotStarted = 0,
[Display(Name = "Weird display name instead of just 'Started'")]
Started = 1,
}
For ASP.Net Core 3.0, this worked for me (credit to previous answerers).
My Enum class:
using System;
using System.Linq;
using System.ComponentModel.DataAnnotations;
using System.Reflection;
public class Enums
{
public enum Duration
{
[Display(Name = "1 Hour")]
OneHour,
[Display(Name = "1 Day")]
OneDay
}
// Helper method to display the name of the enum values.
public static string GetDisplayName(Enum value)
{
return value.GetType()?
.GetMember(value.ToString())?.First()?
.GetCustomAttribute<DisplayAttribute>()?
.Name;
}
}
My View Model Class:
public class MyViewModel
{
public Duration Duration { get; set; }
}
An example of a razor view displaying a label and a drop-down list. Notice the drop-down list does not require a helper method:
#model IEnumerable<MyViewModel>
#foreach (var item in Model)
{
<label asp-for="#item.Duration">#Enums.GetDisplayName(item.Duration)</label>
<div class="form-group">
<label asp-for="#item.Duration" class="control-label">Select Duration</label>
<select asp-for="#item.Duration" class="form-control"
asp-items="Html.GetEnumSelectList<Enums.Duration>()">
</select>
</div>
}
With Core 2.1,
public static string GetDisplayName(Enum enumValue)
{
return enumValue.GetType()?
.GetMember(enumValue.ToString())?[0]?
.GetCustomAttribute<DisplayAttribute>()?
.Name;
}
<ul>
#foreach (int aPromotion in #Enum.GetValues(typeof(UserPromotion)))
{
var currentPromotion = (int)Model.JobSeeker.Promotion;
if ((currentPromotion & aPromotion) == aPromotion)
{
<li>#Html.DisplayFor(e => currentPromotion)</li>
}
}
</ul>
combining all edge-cases together from above:
enum members with base object members' names (Equals, ToString)
optional Display attribute
here is my code:
public enum Enum
{
[Display(Name = "What a weird name!")]
ToString,
Equals
}
public static class EnumHelpers
{
public static string GetDisplayName(this Enum enumValue)
{
var enumType = enumValue.GetType();
return enumType
.GetMember(enumValue.ToString())
.Where(x => x.MemberType == MemberTypes.Field && ((FieldInfo)x).FieldType == enumType)
.First()
.GetCustomAttribute<DisplayAttribute>()?.Name ?? enumValue.ToString();
}
}
void Main()
{
Assert.Equals("What a weird name!", Enum.ToString.GetDisplayName());
Assert.Equals("Equals", Enum.Equals.GetDisplayName());
}
You need to use a bit of reflection in order to access that attribute:
var type = typeof(UserPromotion);
var member = type.GetMember(Model.JobSeeker.Promotion.ToString());
var attributes = member[0].GetCustomAttributes(typeof(DisplayAttribute), false);
var name = ((DisplayAttribute)attributes[0]).Name;
I recommend wrapping this method in a extension method or perform this in a view model.
I'm sorry to do this, but I couldn't use any of the other answers as-is and haven't time to duke it out in the comments.
Uses C# 6 syntax.
static class EnumExtensions
{
/// returns the localized Name, if a [Display(Name="Localised Name")] attribute is applied to the enum member
/// returns null if there isnt an attribute
public static string DisplayNameOrEnumName(this Enum value)
// => value.DisplayNameOrDefault() ?? value.ToString()
{
// More efficient form of ^ based on http://stackoverflow.com/a/17034624/11635
var enumType = value.GetType();
var enumMemberName = Enum.GetName(enumType, value);
return enumType
.GetEnumMemberAttribute<DisplayAttribute>(enumMemberName)
?.GetName() // Potentially localized
?? enumMemberName; // Or fall back to the enum name
}
/// returns the localized Name, if a [Display] attribute is applied to the enum member
/// returns null if there is no attribute
public static string DisplayNameOrDefault(this Enum value) =>
value.GetEnumMemberAttribute<DisplayAttribute>()?.GetName();
static TAttribute GetEnumMemberAttribute<TAttribute>(this Enum value) where TAttribute : Attribute =>
value.GetType().GetEnumMemberAttribute<TAttribute>(value.ToString());
static TAttribute GetEnumMemberAttribute<TAttribute>(this Type enumType, string enumMemberName) where TAttribute : Attribute =>
enumType.GetMember(enumMemberName).Single().GetCustomAttribute<TAttribute>();
}
Building further on Aydin's and Todd's answers, here is an extension method that also lets you get the name from a resource file
using AppResources;
using System;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
using System.Resources;
public static class EnumExtensions
{
public static string GetDisplayName(this Enum enumValue)
{
var enumMember= enumValue.GetType()
.GetMember(enumValue.ToString());
DisplayAttribute displayAttrib = null;
if (enumMember.Any()) {
displayAttrib = enumMember
.First()
.GetCustomAttribute<DisplayAttribute>();
}
string name = null;
Type resource = null;
if (displayAttrib != null)
{
name = displayAttrib.Name;
resource = displayAttrib.ResourceType;
}
return String.IsNullOrEmpty(name) ? enumValue.ToString()
: resource == null ? name
: new ResourceManager(resource).GetString(name);
}
}
and use it like
public enum Season
{
[Display(ResourceType = typeof(Resource), Name = Season_Summer")]
Summer
}
For just displaying enum's display name attribute just use
Microsoft.AspNetCore.Mvc.Rendering's
#Html.DisplayFor(x => EnumType.EnumValue)
That's would be enough.
For displaying SelectList write as following:
<select id="someIdForTheEndPoint" asp-items="Html.GetEnumSelectList<EnumType>()">
<option selected="selected" value="">Select value</option>
</select>
I have two solutions for this Question.
The first solution is on getting display names from enum.
public enum CourseLocationTypes
{
[Display(Name = "On Campus")]
OnCampus,
[Display(Name = "Online")]
Online,
[Display(Name = "Both")]
Both
}
public static string DisplayName(this Enum value)
{
Type enumType = value.GetType();
string enumValue = Enum.GetName(enumType, value);
MemberInfo member = enumType.GetMember(enumValue)[0];
object[] attrs = member.GetCustomAttributes(typeof(DisplayAttribute), false);
string outString = ((DisplayAttribute)attrs[0]).Name;
if (((DisplayAttribute)attrs[0]).ResourceType != null)
{
outString = ((DisplayAttribute)attrs[0]).GetName();
}
return outString;
}
<h3 class="product-title white">#Model.CourseLocationType.DisplayName()</h3>
The second Solution is on getting display name from enum name but that will be enum split in developer language it's called patch.
public static string SplitOnCapitals(this string text)
{
var r = new Regex(#"
(?<=[A-Z])(?=[A-Z][a-z]) |
(?<=[^A-Z])(?=[A-Z]) |
(?<=[A-Za-z])(?=[^A-Za-z])", RegexOptions.IgnorePatternWhitespace);
return r.Replace(text, " ");
}
<div class="widget-box pt-0">
#foreach (var item in Enum.GetNames(typeof(CourseLocationType)))
{
<label class="pr-2 pt-1">
#Html.RadioButtonFor(x => x.CourseLocationType, item, new { type = "radio", #class = "iCheckBox control-label" }) #item.SplitOnCapitals()
</label>
}
#Html.ValidationMessageFor(x => x.CourseLocationType)
</div>
2020 Update: An updated version of the function provided by many in this thread but now for C# 7.3 onwards:
Now you can restrict generic methods to enums types so you can write a single method extension to use it with all your enums like this:
The generic extension method:
public static string ATexto<T>(this T enumeraci贸n) where T : struct, Enum {
var tipo = enumeraci贸n.GetType();
return tipo.GetMember(enumeraci贸n.ToString())
.Where(x => x.MemberType == MemberTypes.Field && ((FieldInfo)x).FieldType == tipo).First()
.GetCustomAttribute<DisplayAttribute>()?.Name ?? enumeraci贸n.ToString();
}
The enum:
public enum TipoImpuesto {
IVA, INC, [Display(Name = "IVA e INC")]IVAeINC, [Display(Name = "No aplica")]NoAplica };
How to use it:
var tipoImpuesto = TipoImpuesto.IVAeINC;
var textoTipoImpuesto = tipoImpuesto.ATexto(); // Prints "IVA e INC".
Bonus, Enums with Flags: If you are dealing with normal enums the function above is enough, but if any of your enums can take multiple values with the use of flags then you will need to modify it like this (This code uses C#8 features):
public static string ATexto<T>(this T enumeraci贸n) where T : struct, Enum {
var tipo = enumeraci贸n.GetType();
var textoDirecto = enumeraci贸n.ToString();
string obtenerTexto(string textoDirecto) => tipo.GetMember(textoDirecto)
.Where(x => x.MemberType == MemberTypes.Field && ((FieldInfo)x).FieldType == tipo)
.First().GetCustomAttribute<DisplayAttribute>()?.Name ?? textoDirecto;
if (textoDirecto.Contains(", ")) {
var texto = new StringBuilder();
foreach (var textoDirectoAux in textoDirecto.Split(", ")) {
texto.Append($"{obtenerTexto(textoDirectoAux)}, ");
}
return texto.ToString()[0..^2];
} else {
return obtenerTexto(textoDirecto);
}
}
The enum with flags:
[Flags] public enum TipoContribuyente {
[Display(Name = "Com煤n")] Com煤n = 1,
[Display(Name = "Gran Contribuyente")] GranContribuyente = 2,
Autorretenedor = 4,
[Display(Name = "Retenedor de IVA")] RetenedorIVA = 8,
[Display(Name = "R茅gimen Simple")] R茅gimenSimple = 16 }
How to use it:
var tipoContribuyente = TipoContribuyente.RetenedorIVA | TipoContribuyente.GranContribuyente;
var textoAux = tipoContribuyente.ATexto(); // Prints "Gran Contribuyente, Retenedor de IVA".
I want to contribute with culture-dependent GetDisplayName enum extension. Hope this will be usefull for anyone googling this answer like me previously:
"standart" way as Aydin Adn and Todd mentioned:
public static string GetDisplayName(this Enum enumValue)
{
return enumValue
.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>()
.GetName();
}
"Culture-dependent" way:
public static string GetDisplayName(this Enum enumValue, CultureInfo ci)
{
var displayAttr = enumValue
.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>();
var resMan = displayAttr.ResourceType?.GetProperty(#"ResourceManager", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).GetValue(null, null) as ResourceManager;
return resMan?.GetString(displayAttr.Name, ci) ?? displayAttr.GetName();
}
It is maybe cheating, but it's works:
#foreach (var yourEnum in Html.GetEnumSelectList<YourEnum>())
{
#yourEnum.Text
}
Based on previous answers I've created this comfortable helper to support all DisplayAttribute properties in a readable way:
public static class EnumExtensions
{
public static DisplayAttributeValues GetDisplayAttributeValues(this Enum enumValue)
{
var displayAttribute = enumValue.GetType().GetMember(enumValue.ToString()).First().GetCustomAttribute<DisplayAttribute>();
return new DisplayAttributeValues(enumValue, displayAttribute);
}
public sealed class DisplayAttributeValues
{
private readonly Enum enumValue;
private readonly DisplayAttribute displayAttribute;
public DisplayAttributeValues(Enum enumValue, DisplayAttribute displayAttribute)
{
this.enumValue = enumValue;
this.displayAttribute = displayAttribute;
}
public bool? AutoGenerateField => this.displayAttribute?.GetAutoGenerateField();
public bool? AutoGenerateFilter => this.displayAttribute?.GetAutoGenerateFilter();
public int? Order => this.displayAttribute?.GetOrder();
public string Description => this.displayAttribute != null ? this.displayAttribute.GetDescription() : string.Empty;
public string GroupName => this.displayAttribute != null ? this.displayAttribute.GetGroupName() : string.Empty;
public string Name => this.displayAttribute != null ? this.displayAttribute.GetName() : this.enumValue.ToString();
public string Prompt => this.displayAttribute != null ? this.displayAttribute.GetPrompt() : string.Empty;
public string ShortName => this.displayAttribute != null ? this.displayAttribute.GetShortName() : this.enumValue.ToString();
}
}
I tried doing this as an edit but it was rejected; I can't see why.
The above will throw an exception if you call it with an Enum that has a mix of custom attributes and plain items, e.g.
public enum CommentType
{
All = 1,
Rent = 2,
Insurance = 3,
[Display(Name="Service Charge")]
ServiceCharge = 4
}
So I've modified the code ever so slightly to check for custom attributes before trying to access them, and use the name if none are found.
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
public static class EnumHelper<T>
{
public static IList<T> GetValues(Enum value)
{
var enumValues = new List<T>();
foreach (FieldInfo fi in value.GetType().GetFields(BindingFlags.Static | BindingFlags.Public))
{
enumValues.Add((T)Enum.Parse(value.GetType(), fi.Name, false));
}
return enumValues;
}
public static T Parse(string value)
{
return (T)Enum.Parse(typeof(T), value, true);
}
public static IList<string> GetNames(Enum value)
{
return value.GetType().GetFields(BindingFlags.Static | BindingFlags.Public).Select(fi => fi.Name).ToList();
}
public static IList<string> GetDisplayValues(Enum value)
{
return GetNames(value).Select(obj => GetDisplayValue(Parse(obj))).ToList();
}
private static string lookupResource(Type resourceManagerProvider, string resourceKey)
{
foreach (PropertyInfo staticProperty in resourceManagerProvider.GetProperties(BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public))
{
if (staticProperty.PropertyType == typeof(System.Resources.ResourceManager))
{
System.Resources.ResourceManager resourceManager = (System.Resources.ResourceManager)staticProperty.GetValue(null, null);
return resourceManager.GetString(resourceKey);
}
}
return resourceKey; // Fallback with the key name
}
public static string GetDisplayValue(T value)
{
var fieldInfo = value.GetType().GetField(value.ToString());
var descriptionAttributes = fieldInfo.GetCustomAttributes(
typeof(DisplayAttribute), false) as DisplayAttribute[];
if (descriptionAttributes.Any() && descriptionAttributes[0].ResourceType != null)
return lookupResource(descriptionAttributes[0].ResourceType, descriptionAttributes[0].Name);
if (descriptionAttributes == null) return string.Empty;
return (descriptionAttributes.Length > 0) ? descriptionAttributes[0].Name : value.ToString();
}
}
Using MVC5 you could use:
public enum UserPromotion
{
None = 0x0,
[Display(Name = "Send Job Offers By Mail")]
SendJobOffersByMail = 0x1,
[Display(Name = "Send Job Offers By Sms")]
SendJobOffersBySms = 0x2,
[Display(Name = "Send Other Stuff By Sms")]
SendPromotionalBySms = 0x4,
[Display(Name = "Send Other Stuff By Mail")]
SendPromotionalByMail = 0x8
}
then if you want to create a dropdown selector you can use:
#Html.EnumDropdownListFor(expression: model => model.PromotionSelector, optionLabel: "Select")
assume that your enum name is OrderState, Use this code:
#Html.DropDownList("selectList", new SelectList(Html.GetEnumSelectList<OrderState>(), "Value", "Text",ViewBag.selectedOrderState), new {#id="OrderState", #class = "form-control" })
and set selected option in backend:
var selectedOrderState = ..Data.OrderState.GetHashCode();
ViewBag.selectedOrderState = selectedOrderState;
I have a method to update some customer information
public UpdateCustomerInformationResponse UpdateCustomerInformation(UpdateCustomerInformationRequest request)
{
var customer = new Customer
{
FirstName = request.Customer
LastName = request.LastName,
MiddleInitial = request.MiddleInitial,
CustomerEmail = request.CustomerEmail,
UnitNumber = request.UnitNumber,
}
Another object
var fieldRequired = new FieldRequired{
FieldName = "CustomerEmail ",
IsRequired = 1
}
I want to compare 2 objects so that I can find out if FieldName "CustomerEmail"
is present in Customer object.
Its so simple buddy. I found a simple solution using the reflection and extnetion method just follow as below
Create a static class with the name "CompareTwoObjects" and add the code to it.
public static object CompareEquals(this T objectFromCompare, T objectToCompare)//Generic method
{
if (objectFromCompare == null && objectToCompare == null)
return true;
else if (objectFromCompare == null && objectToCompare != null)
return false;
else if (objectFromCompare != null && objectToCompare == null)
return false;
//Gets all the properties of the class
PropertyInfo[] props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
foreach (PropertyInfo prop in props)
{
object dataFromCompare = objectFromCompare.GetType().GetProperty(prop.Name).GetValue(objectFromCompare, null);
object dataToCompare = objectToCompare.GetType().GetProperty(prop.Name).GetValue(objectToCompare, null);
Type type = objectFromCompare.GetType().GetProperty(prop.Name).GetValue(objectToCompare, null).GetType();
if (prop.PropertyType.IsClass && !prop.PropertyType.FullName.Contains("System.String"))
{
dynamic convertedFromValue = Convert.ChangeType(dataFromCompare, type);
dynamic convertedToValue = Convert.ChangeType(dataToCompare, type);
object result = CompareTwoObjects.CompareEquals(convertedFromValue, convertedToValue);
bool compareResult = (bool)result;
if (!compareResult)
return false;
}
else if (!dataFromCompare.Equals(dataToCompare))
return false;
}
return true;
}
This will give the result of two objects are having same values or not.
Usage:-
Object1.CompareEquals(Object2);
If the class object is complex also this will work. If you found any issues please post back
Your question is a little vague. Is this what you are looking for?
if (fieldRequired.FieldName == "CustomerEmail" && fieldRequired.IsRequired == 1)
{
CustomerEmail = request.CustomerEmail;
}
You can implement the interface IEqualtable, then design the method Equals with the data members that you want to compare. You can see an example of this implementation below:
class Customer: IEquatable<Customer>
{
public string FirstName { get; set; }
public string LastName { get; set; }
...
public bool Equals(Person other)
{
return ((FirstName == other.FirstName) &&
(LastName == other.LastName));
}
}
I've got a property in my model called Promotion that its type is a flag enum called UserPromotion. Members of my enum have display attributes set as follows:
[Flags]
public enum UserPromotion
{
None = 0x0,
[Display(Name = "Send Job Offers By Mail")]
SendJobOffersByMail = 0x1,
[Display(Name = "Send Job Offers By Sms")]
SendJobOffersBySms = 0x2,
[Display(Name = "Send Other Stuff By Sms")]
SendPromotionalBySms = 0x4,
[Display(Name = "Send Other Stuff By Mail")]
SendPromotionalByMail = 0x8
}
Now I want to be able to create say a ul in my view to show the selected values of my Promotion property. This is what I have done so far but the problem is that how can I get the display names here?
<ul>
#foreach (int aPromotion in #Enum.GetValues(typeof(UserPromotion)))
{
var currentPromotion = (int)Model.JobSeeker.Promotion;
if ((currentPromotion & aPromotion) == aPromotion)
{
<li>Here I don't know how to get the display attribute of "currentPromotion".</li>
}
}
</ul>
One liner - Fluent syntax
public static class Extensions
{
/// <summary>
/// A generic extension method that aids in reflecting
/// and retrieving any attribute that is applied to an `Enum`.
/// </summary>
public static TAttribute GetAttribute<TAttribute>(this Enum enumValue)
where TAttribute : Attribute
{
return enumValue.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<TAttribute>();
}
}
Example
public enum Season
{
[Display(Name = "It's autumn")]
Autumn,
[Display(Name = "It's winter")]
Winter,
[Display(Name = "It's spring")]
Spring,
[Display(Name = "It's summer")]
Summer
}
public class Foo
{
public Season Season = Season.Summer;
public void DisplayName()
{
var seasonDisplayName = Season.GetAttribute<DisplayAttribute>();
Console.WriteLine("Which season is it?");
Console.WriteLine (seasonDisplayName.Name);
}
}
Output
Which season is it?
It's summer
UPDATE
First solution was focused on getting display names from enum. Code below should be exact solution for your problem.
You can use this helper class for enums:
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
public static class EnumHelper<T>
where T : struct, Enum // This constraint requires C# 7.3 or later.
{
public static IList<T> GetValues(Enum value)
{
var enumValues = new List<T>();
foreach (FieldInfo fi in value.GetType().GetFields(BindingFlags.Static | BindingFlags.Public))
{
enumValues.Add((T)Enum.Parse(value.GetType(), fi.Name, false));
}
return enumValues;
}
public static T Parse(string value)
{
return (T)Enum.Parse(typeof(T), value, true);
}
public static IList<string> GetNames(Enum value)
{
return value.GetType().GetFields(BindingFlags.Static | BindingFlags.Public).Select(fi => fi.Name).ToList();
}
public static IList<string> GetDisplayValues(Enum value)
{
return GetNames(value).Select(obj => GetDisplayValue(Parse(obj))).ToList();
}
private static string lookupResource(Type resourceManagerProvider, string resourceKey)
{
var resourceKeyProperty = resourceManagerProvider.GetProperty(resourceKey,
BindingFlags.Static | BindingFlags.Public, null, typeof(string),
new Type[0], null);
if (resourceKeyProperty != null)
{
return (string)resourceKeyProperty.GetMethod.Invoke(null, null);
}
return resourceKey; // Fallback with the key name
}
public static string GetDisplayValue(T value)
{
var fieldInfo = value.GetType().GetField(value.ToString());
var descriptionAttributes = fieldInfo.GetCustomAttributes(
typeof(DisplayAttribute), false) as DisplayAttribute[];
if (descriptionAttributes[0].ResourceType != null)
return lookupResource(descriptionAttributes[0].ResourceType, descriptionAttributes[0].Name);
if (descriptionAttributes == null) return string.Empty;
return (descriptionAttributes.Length > 0) ? descriptionAttributes[0].Name : value.ToString();
}
}
And then you can use it in your view as following:
<ul>
#foreach (var value in #EnumHelper<UserPromotion>.GetValues(UserPromotion.None))
{
if (value == Model.JobSeeker.Promotion)
{
var description = EnumHelper<UserPromotion>.GetDisplayValue(value);
<li>#Html.DisplayFor(e => description )</li>
}
}
</ul>
Building on Aydin's great answer, here's an extension method that doesn't require any type parameters.
using System;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
public static class EnumExtensions
{
public static string GetDisplayName(this Enum enumValue)
{
return enumValue.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>()
.GetName();
}
}
NOTE: GetName() should be used instead of the Name property. This ensures that the localized string will be returned if using the ResourceType attribute property.
Example
To use it, just reference the enum value in your view.
#{
UserPromotion promo = UserPromotion.SendJobOffersByMail;
}
Promotion: #promo.GetDisplayName()
Output
Promotion: Send Job Offers By Mail
Based on Aydin's answer I would suggest a less "duplicatious" implementation (because we could easily get the Type from the Enum value itself, instead of providing it as a parameter 馃槈:
using System;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
public static string GetDisplayName(this Enum enumValue)
{
return enumValue.GetType().GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>()
.Name;
}
EDIT (based upon #Vahagn Nahapetyan's comment)
public static string GetDisplayName(this Enum enumValue)
{
return enumValue.GetType()?
.GetMember(enumValue.ToString())?
.First()?
.GetCustomAttribute<DisplayAttribute>()?
.Name;
}
Now we can use it very clean in this way:
public enum Season
{
[Display(Name = "The Autumn")]
Autumn,
[Display(Name = "The Weather")]
Winter,
[Display(Name = "The Tease")]
Spring,
[Display(Name = "The Dream")]
Summer
}
Season.Summer.GetDisplayName();
Which results in
"The Dream"
If you are using MVC 5.1 or upper there is simplier and clearer way: just use data annotation (from System.ComponentModel.DataAnnotations namespace) like below:
public enum Color
{
[Display(Name = "Dark red")]
DarkRed,
[Display(Name = "Very dark red")]
VeryDarkRed,
[Display(Name = "Red or just black?")]
ReallyDarkRed
}
And in view, just put it into proper html helper:
#Html.EnumDropDownListFor(model => model.Color)
Building on Todd's great answer which built on Aydin's great answer, here's a generic extension method which doesn't require any type parameters.
/// <summary>
/// Gets human-readable version of enum.
/// </summary>
/// <returns>effective DisplayAttribute.Name of given enum.</returns>
public static string GetDisplayName<T>(this T enumValue) where T : IComparable, IFormattable, IConvertible // C# 7.3+: where T : struct, Enum
{
if (!typeof(T).IsEnum) // Not needed in C# 7.3+ with above updated constraint
throw new ArgumentException("Argument must be of type Enum");
DisplayAttribute displayAttribute = enumValue.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>();
string displayName = displayAttribute?.GetName();
return displayName ?? enumValue.ToString();
}
I needed this for my project because something like the below code, where not every member of the enum has a DisplayAttribute, throws an exception with Todd's solution:
public class MyClass
{
public enum MyEnum
{
[Display(Name="ONE")]
One,
// No DisplayAttribute
Two
}
public void UseMyEnum()
{
MyEnum foo = MyEnum.One;
MyEnum bar = MyEnum.Two;
Console.WriteLine(foo.GetDisplayName());
Console.WriteLine(bar.GetDisplayName());
}
}
// Output:
//
// ONE
// Two
If this is a complicated solution to a simple problem, please let me know, but this was the fix I used.
You could use Type.GetMember Method, then get the attribute info using reflection:
// display attribute of "currentPromotion"
var type = typeof(UserPromotion);
var memberInfo = type.GetMember(currentPromotion.ToString());
var attributes = memberInfo[0].GetCustomAttributes(typeof(DisplayAttribute), false);
var description = ((DisplayAttribute)attributes[0]).Name;
There were a few similar posts here:
Getting attributes of Enum's value
How to make MVC3 DisplayFor show the value of an Enum's Display-Attribute?
In .NET5, I used DisplayTextFor without needing helper or extension methods:
#Html.DisplayTextFor(m => m.SomeEnumProperty)
Where SomeEnumProperty has a value of:
public enum MyEnum
{
[Display(Name = "Not started")]
NotStarted = 0,
[Display(Name = "Weird display name instead of just 'Started'")]
Started = 1,
}
For ASP.Net Core 3.0, this worked for me (credit to previous answerers).
My Enum class:
using System;
using System.Linq;
using System.ComponentModel.DataAnnotations;
using System.Reflection;
public class Enums
{
public enum Duration
{
[Display(Name = "1 Hour")]
OneHour,
[Display(Name = "1 Day")]
OneDay
}
// Helper method to display the name of the enum values.
public static string GetDisplayName(Enum value)
{
return value.GetType()?
.GetMember(value.ToString())?.First()?
.GetCustomAttribute<DisplayAttribute>()?
.Name;
}
}
My View Model Class:
public class MyViewModel
{
public Duration Duration { get; set; }
}
An example of a razor view displaying a label and a drop-down list. Notice the drop-down list does not require a helper method:
#model IEnumerable<MyViewModel>
#foreach (var item in Model)
{
<label asp-for="#item.Duration">#Enums.GetDisplayName(item.Duration)</label>
<div class="form-group">
<label asp-for="#item.Duration" class="control-label">Select Duration</label>
<select asp-for="#item.Duration" class="form-control"
asp-items="Html.GetEnumSelectList<Enums.Duration>()">
</select>
</div>
}
With Core 2.1,
public static string GetDisplayName(Enum enumValue)
{
return enumValue.GetType()?
.GetMember(enumValue.ToString())?[0]?
.GetCustomAttribute<DisplayAttribute>()?
.Name;
}
<ul>
#foreach (int aPromotion in #Enum.GetValues(typeof(UserPromotion)))
{
var currentPromotion = (int)Model.JobSeeker.Promotion;
if ((currentPromotion & aPromotion) == aPromotion)
{
<li>#Html.DisplayFor(e => currentPromotion)</li>
}
}
</ul>
combining all edge-cases together from above:
enum members with base object members' names (Equals, ToString)
optional Display attribute
here is my code:
public enum Enum
{
[Display(Name = "What a weird name!")]
ToString,
Equals
}
public static class EnumHelpers
{
public static string GetDisplayName(this Enum enumValue)
{
var enumType = enumValue.GetType();
return enumType
.GetMember(enumValue.ToString())
.Where(x => x.MemberType == MemberTypes.Field && ((FieldInfo)x).FieldType == enumType)
.First()
.GetCustomAttribute<DisplayAttribute>()?.Name ?? enumValue.ToString();
}
}
void Main()
{
Assert.Equals("What a weird name!", Enum.ToString.GetDisplayName());
Assert.Equals("Equals", Enum.Equals.GetDisplayName());
}
You need to use a bit of reflection in order to access that attribute:
var type = typeof(UserPromotion);
var member = type.GetMember(Model.JobSeeker.Promotion.ToString());
var attributes = member[0].GetCustomAttributes(typeof(DisplayAttribute), false);
var name = ((DisplayAttribute)attributes[0]).Name;
I recommend wrapping this method in a extension method or perform this in a view model.
I'm sorry to do this, but I couldn't use any of the other answers as-is and haven't time to duke it out in the comments.
Uses C# 6 syntax.
static class EnumExtensions
{
/// returns the localized Name, if a [Display(Name="Localised Name")] attribute is applied to the enum member
/// returns null if there isnt an attribute
public static string DisplayNameOrEnumName(this Enum value)
// => value.DisplayNameOrDefault() ?? value.ToString()
{
// More efficient form of ^ based on http://stackoverflow.com/a/17034624/11635
var enumType = value.GetType();
var enumMemberName = Enum.GetName(enumType, value);
return enumType
.GetEnumMemberAttribute<DisplayAttribute>(enumMemberName)
?.GetName() // Potentially localized
?? enumMemberName; // Or fall back to the enum name
}
/// returns the localized Name, if a [Display] attribute is applied to the enum member
/// returns null if there is no attribute
public static string DisplayNameOrDefault(this Enum value) =>
value.GetEnumMemberAttribute<DisplayAttribute>()?.GetName();
static TAttribute GetEnumMemberAttribute<TAttribute>(this Enum value) where TAttribute : Attribute =>
value.GetType().GetEnumMemberAttribute<TAttribute>(value.ToString());
static TAttribute GetEnumMemberAttribute<TAttribute>(this Type enumType, string enumMemberName) where TAttribute : Attribute =>
enumType.GetMember(enumMemberName).Single().GetCustomAttribute<TAttribute>();
}
Building further on Aydin's and Todd's answers, here is an extension method that also lets you get the name from a resource file
using AppResources;
using System;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
using System.Resources;
public static class EnumExtensions
{
public static string GetDisplayName(this Enum enumValue)
{
var enumMember= enumValue.GetType()
.GetMember(enumValue.ToString());
DisplayAttribute displayAttrib = null;
if (enumMember.Any()) {
displayAttrib = enumMember
.First()
.GetCustomAttribute<DisplayAttribute>();
}
string name = null;
Type resource = null;
if (displayAttrib != null)
{
name = displayAttrib.Name;
resource = displayAttrib.ResourceType;
}
return String.IsNullOrEmpty(name) ? enumValue.ToString()
: resource == null ? name
: new ResourceManager(resource).GetString(name);
}
}
and use it like
public enum Season
{
[Display(ResourceType = typeof(Resource), Name = Season_Summer")]
Summer
}
For just displaying enum's display name attribute just use
Microsoft.AspNetCore.Mvc.Rendering's
#Html.DisplayFor(x => EnumType.EnumValue)
That's would be enough.
For displaying SelectList write as following:
<select id="someIdForTheEndPoint" asp-items="Html.GetEnumSelectList<EnumType>()">
<option selected="selected" value="">Select value</option>
</select>
I have two solutions for this Question.
The first solution is on getting display names from enum.
public enum CourseLocationTypes
{
[Display(Name = "On Campus")]
OnCampus,
[Display(Name = "Online")]
Online,
[Display(Name = "Both")]
Both
}
public static string DisplayName(this Enum value)
{
Type enumType = value.GetType();
string enumValue = Enum.GetName(enumType, value);
MemberInfo member = enumType.GetMember(enumValue)[0];
object[] attrs = member.GetCustomAttributes(typeof(DisplayAttribute), false);
string outString = ((DisplayAttribute)attrs[0]).Name;
if (((DisplayAttribute)attrs[0]).ResourceType != null)
{
outString = ((DisplayAttribute)attrs[0]).GetName();
}
return outString;
}
<h3 class="product-title white">#Model.CourseLocationType.DisplayName()</h3>
The second Solution is on getting display name from enum name but that will be enum split in developer language it's called patch.
public static string SplitOnCapitals(this string text)
{
var r = new Regex(#"
(?<=[A-Z])(?=[A-Z][a-z]) |
(?<=[^A-Z])(?=[A-Z]) |
(?<=[A-Za-z])(?=[^A-Za-z])", RegexOptions.IgnorePatternWhitespace);
return r.Replace(text, " ");
}
<div class="widget-box pt-0">
#foreach (var item in Enum.GetNames(typeof(CourseLocationType)))
{
<label class="pr-2 pt-1">
#Html.RadioButtonFor(x => x.CourseLocationType, item, new { type = "radio", #class = "iCheckBox control-label" }) #item.SplitOnCapitals()
</label>
}
#Html.ValidationMessageFor(x => x.CourseLocationType)
</div>
2020 Update: An updated version of the function provided by many in this thread but now for C# 7.3 onwards:
Now you can restrict generic methods to enums types so you can write a single method extension to use it with all your enums like this:
The generic extension method:
public static string ATexto<T>(this T enumeraci贸n) where T : struct, Enum {
var tipo = enumeraci贸n.GetType();
return tipo.GetMember(enumeraci贸n.ToString())
.Where(x => x.MemberType == MemberTypes.Field && ((FieldInfo)x).FieldType == tipo).First()
.GetCustomAttribute<DisplayAttribute>()?.Name ?? enumeraci贸n.ToString();
}
The enum:
public enum TipoImpuesto {
IVA, INC, [Display(Name = "IVA e INC")]IVAeINC, [Display(Name = "No aplica")]NoAplica };
How to use it:
var tipoImpuesto = TipoImpuesto.IVAeINC;
var textoTipoImpuesto = tipoImpuesto.ATexto(); // Prints "IVA e INC".
Bonus, Enums with Flags: If you are dealing with normal enums the function above is enough, but if any of your enums can take multiple values with the use of flags then you will need to modify it like this (This code uses C#8 features):
public static string ATexto<T>(this T enumeraci贸n) where T : struct, Enum {
var tipo = enumeraci贸n.GetType();
var textoDirecto = enumeraci贸n.ToString();
string obtenerTexto(string textoDirecto) => tipo.GetMember(textoDirecto)
.Where(x => x.MemberType == MemberTypes.Field && ((FieldInfo)x).FieldType == tipo)
.First().GetCustomAttribute<DisplayAttribute>()?.Name ?? textoDirecto;
if (textoDirecto.Contains(", ")) {
var texto = new StringBuilder();
foreach (var textoDirectoAux in textoDirecto.Split(", ")) {
texto.Append($"{obtenerTexto(textoDirectoAux)}, ");
}
return texto.ToString()[0..^2];
} else {
return obtenerTexto(textoDirecto);
}
}
The enum with flags:
[Flags] public enum TipoContribuyente {
[Display(Name = "Com煤n")] Com煤n = 1,
[Display(Name = "Gran Contribuyente")] GranContribuyente = 2,
Autorretenedor = 4,
[Display(Name = "Retenedor de IVA")] RetenedorIVA = 8,
[Display(Name = "R茅gimen Simple")] R茅gimenSimple = 16 }
How to use it:
var tipoContribuyente = TipoContribuyente.RetenedorIVA | TipoContribuyente.GranContribuyente;
var textoAux = tipoContribuyente.ATexto(); // Prints "Gran Contribuyente, Retenedor de IVA".
I want to contribute with culture-dependent GetDisplayName enum extension. Hope this will be usefull for anyone googling this answer like me previously:
"standart" way as Aydin Adn and Todd mentioned:
public static string GetDisplayName(this Enum enumValue)
{
return enumValue
.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>()
.GetName();
}
"Culture-dependent" way:
public static string GetDisplayName(this Enum enumValue, CultureInfo ci)
{
var displayAttr = enumValue
.GetType()
.GetMember(enumValue.ToString())
.First()
.GetCustomAttribute<DisplayAttribute>();
var resMan = displayAttr.ResourceType?.GetProperty(#"ResourceManager", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).GetValue(null, null) as ResourceManager;
return resMan?.GetString(displayAttr.Name, ci) ?? displayAttr.GetName();
}
It is maybe cheating, but it's works:
#foreach (var yourEnum in Html.GetEnumSelectList<YourEnum>())
{
#yourEnum.Text
}
Based on previous answers I've created this comfortable helper to support all DisplayAttribute properties in a readable way:
public static class EnumExtensions
{
public static DisplayAttributeValues GetDisplayAttributeValues(this Enum enumValue)
{
var displayAttribute = enumValue.GetType().GetMember(enumValue.ToString()).First().GetCustomAttribute<DisplayAttribute>();
return new DisplayAttributeValues(enumValue, displayAttribute);
}
public sealed class DisplayAttributeValues
{
private readonly Enum enumValue;
private readonly DisplayAttribute displayAttribute;
public DisplayAttributeValues(Enum enumValue, DisplayAttribute displayAttribute)
{
this.enumValue = enumValue;
this.displayAttribute = displayAttribute;
}
public bool? AutoGenerateField => this.displayAttribute?.GetAutoGenerateField();
public bool? AutoGenerateFilter => this.displayAttribute?.GetAutoGenerateFilter();
public int? Order => this.displayAttribute?.GetOrder();
public string Description => this.displayAttribute != null ? this.displayAttribute.GetDescription() : string.Empty;
public string GroupName => this.displayAttribute != null ? this.displayAttribute.GetGroupName() : string.Empty;
public string Name => this.displayAttribute != null ? this.displayAttribute.GetName() : this.enumValue.ToString();
public string Prompt => this.displayAttribute != null ? this.displayAttribute.GetPrompt() : string.Empty;
public string ShortName => this.displayAttribute != null ? this.displayAttribute.GetShortName() : this.enumValue.ToString();
}
}
I tried doing this as an edit but it was rejected; I can't see why.
The above will throw an exception if you call it with an Enum that has a mix of custom attributes and plain items, e.g.
public enum CommentType
{
All = 1,
Rent = 2,
Insurance = 3,
[Display(Name="Service Charge")]
ServiceCharge = 4
}
So I've modified the code ever so slightly to check for custom attributes before trying to access them, and use the name if none are found.
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Reflection;
public static class EnumHelper<T>
{
public static IList<T> GetValues(Enum value)
{
var enumValues = new List<T>();
foreach (FieldInfo fi in value.GetType().GetFields(BindingFlags.Static | BindingFlags.Public))
{
enumValues.Add((T)Enum.Parse(value.GetType(), fi.Name, false));
}
return enumValues;
}
public static T Parse(string value)
{
return (T)Enum.Parse(typeof(T), value, true);
}
public static IList<string> GetNames(Enum value)
{
return value.GetType().GetFields(BindingFlags.Static | BindingFlags.Public).Select(fi => fi.Name).ToList();
}
public static IList<string> GetDisplayValues(Enum value)
{
return GetNames(value).Select(obj => GetDisplayValue(Parse(obj))).ToList();
}
private static string lookupResource(Type resourceManagerProvider, string resourceKey)
{
foreach (PropertyInfo staticProperty in resourceManagerProvider.GetProperties(BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public))
{
if (staticProperty.PropertyType == typeof(System.Resources.ResourceManager))
{
System.Resources.ResourceManager resourceManager = (System.Resources.ResourceManager)staticProperty.GetValue(null, null);
return resourceManager.GetString(resourceKey);
}
}
return resourceKey; // Fallback with the key name
}
public static string GetDisplayValue(T value)
{
var fieldInfo = value.GetType().GetField(value.ToString());
var descriptionAttributes = fieldInfo.GetCustomAttributes(
typeof(DisplayAttribute), false) as DisplayAttribute[];
if (descriptionAttributes.Any() && descriptionAttributes[0].ResourceType != null)
return lookupResource(descriptionAttributes[0].ResourceType, descriptionAttributes[0].Name);
if (descriptionAttributes == null) return string.Empty;
return (descriptionAttributes.Length > 0) ? descriptionAttributes[0].Name : value.ToString();
}
}
Using MVC5 you could use:
public enum UserPromotion
{
None = 0x0,
[Display(Name = "Send Job Offers By Mail")]
SendJobOffersByMail = 0x1,
[Display(Name = "Send Job Offers By Sms")]
SendJobOffersBySms = 0x2,
[Display(Name = "Send Other Stuff By Sms")]
SendPromotionalBySms = 0x4,
[Display(Name = "Send Other Stuff By Mail")]
SendPromotionalByMail = 0x8
}
then if you want to create a dropdown selector you can use:
#Html.EnumDropdownListFor(expression: model => model.PromotionSelector, optionLabel: "Select")
assume that your enum name is OrderState, Use this code:
#Html.DropDownList("selectList", new SelectList(Html.GetEnumSelectList<OrderState>(), "Value", "Text",ViewBag.selectedOrderState), new {#id="OrderState", #class = "form-control" })
and set selected option in backend:
var selectedOrderState = ..Data.OrderState.GetHashCode();
ViewBag.selectedOrderState = selectedOrderState;
So I need to get a List<string> from my enum
Here is what I have done so far:
enum definition
[Flags]
public enum ContractorType
{
[Description("Recipient")]
RECIPIENT = 1,
[Description("Deliver")]
DELIVER = 2,
[Description("Recipient / Deliver")]
RECIPIENT_DELIVER = 4
}
HelperClass with method to do what I need:
public static class EnumUtils
{
public static IEnumerable<string> GetDescrptions(Type enumerator)
{
FieldInfo[] fi = enumerator.GetFields();
List<DescriptionAttribute> attributes = new List<DescriptionAttribute>();
foreach (var i in fi)
{
try
{
yield return attributes.Add(((DescriptionAttribute[])i.GetCustomAttributes(
typeof(DescriptionAttribute),
false))[0]);
}
catch { }
}
return new List<string>{"empty"};
}
}
Now in the line where I yield values, I got a NullReferenceException. Did I miss something? The syntax looks all right to me, but maybe I overlooked something?
Edit:
I'm using .net Framework 4.0 here.
This generic static method works fine for getting a list of descriptions for each value of an enum type of T:
public static IEnumerable<string> GetDescriptions<T>()
{
var attributes = typeof(T).GetMembers()
.SelectMany(member => member.GetCustomAttributes(typeof (DescriptionAttribute), true).Cast<DescriptionAttribute>())
.ToList();
return attributes.Select(x => x.Description);
}
I created these extension methods
public static class EnumExtender
{
public static string GetDescription(this Enum enumValue)
{
string output = null;
Type type = enumValue.GetType();
FieldInfo fi = type.GetField(enumValue.ToString());
var attrs = fi.GetCustomAttributes(typeof(DescriptionAttribute), false) as DescriptionAttribute[];
if (attrs.Length > 0) output = attrs[0].Description;
return output;
}
public static IDictionary<T, string> GetEnumValuesWithDescription<T>(this Type type) where T : struct, IConvertible
{
if (!type.IsEnum)
{
throw new ArgumentException("T must be an enumerated type");
}
return type.GetEnumValues()
.OfType<T>()
.ToDictionary(
key => key,
val => (val as Enum).GetDescription()
);
}
}
Usage
var stuff = typeof(TestEnum).GetEnumValuesWithDescription<TestEnum>();
Will return a Dictionary<TestEnum, string> with value as keys and descriptions as values. If you want just a list, you can change .ToDictionary to
.Select(o => (o as Enum).GetDescription())
.ToList()
Here is a small reusable solution. This is an abstract class which will extract all the attributes of type K from type T.
abstract class AbstractAttributes<T, K>
{
protected List<K> Attributes = new List<K>();
public AbstractAttributes()
{
foreach (var member in typeof(T).GetMembers())
{
foreach (K attribute in member.GetCustomAttributes(typeof(K), true))
Attributes.Add(attribute);
}
}
}
Should we now want to extract only attributes of DescriptionAttribute type, we would use the following class.
class DescriptionAttributes<T> : AbstractAttributes<T, DescriptionAttribute>
{
public List<string> Descriptions { get; set; }
public DescriptionAttributes()
{
Descriptions = Attributes.Select(x => x.Description).ToList();
}
}
This class will extract only attributes of DescriptionAttribute type from the type T. But to actually use this class in you context you will simply need to do the following.
new DescriptionAttributes<ContractorType>().Descriptions.ForEach(x => Console.WriteLine(x));
This line of code will write out all the descriptions you used as parameters in your attributes of type DescriptionAttribute. Should you need to extract some other attributes, just create a new class that derives from the AbstractAttributes<T, K> class and close its type K with the appropriate attribute.
You need to find the DescriptionAttribute on each field, if it exists and then retrieve the Description attribute e.g.
return enumType.GetFields()
.Select(f => (DescriptionAttribute)f.GetCustomAttribute(typeof(DescriptionAttribute)))
.Where(a => a != null)
.Select(a => a.Description)
If you could have multiple descriptions on a field, you could do something like:
FieldInfo[] fields = enumType.GetFields();
foreach(FieldInfo field in fields)
{
var descriptionAttributes = field.GetCustomAttributes(false).OfType<DescriptionAttribute>();
foreach(var descAttr in descriptionAttributes)
{
yield return descAttr.Description;
}
}
which is more similar to your existing approach.
It think this can solve your problem. If it is not implemented you can return null or an exception. It depends what you need.
public DescriptionAttribute GetDescription(ContractorType contractorType)
{
MemberInfo memberInfo = typeof(ContractorType).GetMember(contractorType.ToString())
.FirstOrDefault();
if (memberInfo != null)
{
DescriptionAttribute attribute = (DescriptionAttribute)
memberInfo.GetCustomAttributes(typeof(DescriptionAttribute), false)
.FirstOrDefault();
return attribute;
}
//return null;
//or
throw new NotImplementedException("There is no description for this enum");
}
So you will use it like this :
DescriptionAttribute attribute = GetDescription(ContractorType.RECIPIENT);
Sorry that I didn't read your question. Here is some code that you can use to take all of the description strings:
public IEnumerable<string> GetAllDescriptionInText()
{
List<string> descList = new List<string>();
foreach (DescriptionAttribute desc in Enum.GetValues(typeof(DescriptionAttribute)))
{
descList.Add(GetDescription(desc).Value);
}
return descList;
}
You can try this
public string ContractorTypeDescription(Enum ContractorType)
{
FieldInfo fi = ContractorType.GetType().GetField(ContractorType.ToString());
var attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
if (attributes.Length > 0)
{
return attributes[0].Description;
}
else
{
return ContractorType.ToString();
}
}
This is Dictionary not List
But is is something I use
using System.ComponentModel;
using System.Reflection;
using MyExtensions;
namespace MyExtensions
{
public static class Extension
{
public static string GetDescriptionName(this Enum value)
{
Type type = value.GetType();
string name = Enum.GetName(type, value);
if (name == null)
return null;
else
{
FieldInfo field = type.GetField(name);
if (field == null)
return name;
else
{
DescriptionAttribute attr =
Attribute.GetCustomAttribute(field,
typeof(DescriptionAttribute)) as DescriptionAttribute;
if (attr == null)
return name;
else
return attr.Description;
}
}
}
}
}
namespace EnumDescription
{
class Program
{
public enum enumDateCond : byte
{
[Description("Empty")]
Null = 0,
[Description("Not Empty")]
NotNull = 1,
EQ = 2,
LT = 3,
LE = 4,
GE = 14,
GT = 15
};
static void Main(string[] args)
{
enumDateCond x = enumDateCond.Null;
string description = x.GetDescriptionName();
foreach (enumDateCond enm in Enum.GetValues(typeof(enumDateCond)))
{
description = enm.GetDescriptionName();
Console.WriteLine(description);
}
Console.WriteLine("Dictionary");
Dictionary<enumDateCond, string> DLenumDateCond = EnumToDictionary<enumDateCond>();
foreach(enumDateCond key in DLenumDateCond.Keys)
{
Console.WriteLine(key.ToString() + " " + DLenumDateCond[key]);
}
}
public static Dictionary<T, string> EnumToDictionary<T>()
where T : struct
{
Type enumType = typeof(T);
// Can't use generic type constraints on value types,
// so have to do check like this
if (enumType.BaseType != typeof(Enum))
throw new ArgumentException("T must be of type System.Enum");
Dictionary<T, string> enumDL = new Dictionary<T, string>();
foreach (T enm in Enum.GetValues(enumType))
{
string name = Enum.GetName(enumType, enm);
if (name != null)
{
FieldInfo field = enumType.GetField(name);
if (field != null)
{
DescriptionAttribute attr =
Attribute.GetCustomAttribute(field,
typeof(DescriptionAttribute)) as DescriptionAttribute;
if (attr != null)
name = attr.Description;
}
}
enumDL.Add(enm, name);
}
return enumDL;
}
}
}