Develop Reference

Enum to list as an extension?

I have various enums that I use as sources for dropdown lists, In order to provide for a user-friendly description, I added a Description attribute to each enum, and then do the following:
var list = Enum.GetValues(typeof(MyEnum))
.Cast<MyEnum>()
.ToDictionary(k => k, v => v.GetAttributeOfType<DescriptionAttribute>().Description)
.ToList();
The above is repetitive because I have to use it in a lot of places. I tried to add an extension method:
public static T GetAttributeOfType<T>(this Enum enumVal) where T : System.Attribute
{
var type = enumVal.GetType();
var memInfo = type.GetMember(enumVal.ToString());
var attributes = memInfo[0].GetCustomAttributes(typeof(T), false);
return (attributes.Length > 0) ? (T)attributes[0] : null;
}
public static KeyValuePair<T, string> ToList<T>(this Enum source)
{
return Enum.GetValues(typeof(T))
.Cast<T>()
.ToDictionary(k => k, v => v.GetAttributeOfType<DescriptionAttribute>().Description)
.ToList();
}
However, I get an exception:
Cannot convert lambda expression to type 'System.Collections.Generic.IEqualityComparer' because it is not a delegate type
What is the correct way to use it as an extension (using the above 2 methods)?

What is the correct way to use it as an extension (using the above 2 methods)?
There is no correct way to use it as an extension. Extension methods (similar to instance methods) are used when you have a value (instance) and for instance want to get some information related to that value. So the extension method would make sense if you want to get the description of a single enum value.
However, in your case the information you need (the list of enum value/description pairs) is not tied to a specific enum value, but to the enum type. Which means you just need a plain static generic method similar to Enum.TryParse<TEnum>. Ideally you would constrain the generic argument to allow only enum, but this type of constraint is not supported (yet), so we'll use (similar to the above system method) just where TEnum : struct and will add runtime check.
So here is a sample implementation:
public static class EnumInfo
{
public static List<KeyValuePair<TEnum, string>> GetList<TEnum>()
where TEnum : struct
{
if (!typeof(TEnum).IsEnum) throw new InvalidOperationException();
return ((TEnum[])Enum.GetValues(typeof(TEnum)))
.ToDictionary(k => k, v => ((Enum)(object)v).GetAttributeOfType<DescriptionAttribute>().Description)
.ToList();
}
}
and usage:
public enum MyEnum
{
[Description("Foo")]
A,
[Description("Bar")]
B,
[Description("Baz")]
C,
}
var list = EnumInfo.GetList<MyEnum>();

I have this extension method in my stack and use it for the same thing all the time.
public static string Description(this Enum #enum)
{
try
{
var #string = #enum.ToString();
var attribute =
#enum.GetType()
.GetField(#string)
.GetCustomAttribute<DescriptionAttribute>(false);
return attribute != null ? attribute.Description : #string;
}
catch // Log nothing, just return an empty string
{
return string.Empty;
}
}
Example usage:
MyEnum.Value.Description(); // The value from within the description attr.
Additionally, you can use this one to get a IDictionary for binding purposes.
public static IDictionary<string, string> ToDictionary(this Type type)
{
if (!type.IsEnum)
{
throw new InvalidCastException("'enumValue' is not an Enumeration!");
}
var names = Enum.GetNames(type);
var values = Enum.GetValues(type);
return Enumerable.Range(0, names.Length)
.Select(index => new
{
Key = names[index],
Value = ((Enum)values.GetValue(index)).Description()
})
.ToDictionary(k => k.Key, k => k.Value);
}
Use it like so:
var dictionary = typeof(MyEnum).ToDictionary();
Update
Here is a working .NET Fiddle.
public static Dictionary<TEnum, string> ToDictionary<TEnum>(this Type type)
where TEnum : struct, IComparable, IFormattable, IConvertible
{
return Enum.GetValues(type)
.OfType<TEnum>()
.ToDictionary(value => value, value => value.Description());
}
Then use it like this:
public enum Test
{
[Description("A test enum value for 'Foo'")]
Foo,
[Description("A test enum value for 'Bar'")]
Bar
}
typeof(Test).ToDictionary<Test>()

You can create a generic method which would take Enum and Attribute as generic argument.
For getting any attribute, you can create an extension method like:
public static string AttributeValue<TEnum,TAttribute>(this TEnum value,Func<TAttribute,string> func) where T : Attribute
{
FieldInfo field = value.GetType().GetField(value.ToString());
T attribute = Attribute.GetCustomAttribute(field, typeof(T)) as T;
return attribute == null ? value.ToString() : func(attribute);
}
and here is the method for converting it to dictionary:
public static Dictionary<TEnum,string> ToDictionary<TEnum,TAttribute>(this TEnum obj,Func<TAttribute,string> func)
where TEnum : struct, IComparable, IFormattable, IConvertible
where TAttribute : Attribute
{
return (Enum.GetValues(typeof(TEnum)).OfType<TEnum>()
.Select(x =>
new
{
Value = x,
Description = x.AttributeValue<TEnum,TAttribute>(func)
}).ToDictionary(x=>x.Value,x=>x.Description));
}
You can call it this way:
var test = eUserRole.SuperAdmin
.ToDictionary<eUserRole,EnumDisplayNameAttribute>(attr=>attr.DisplayName);
I have used this Enum and Attribute as example:
public class EnumDisplayNameAttribute : Attribute
{
private string _displayName;
public string DisplayName
{
get { return _displayName; }
set { _displayName = value; }
}
}
public enum eUserRole : int
{
[EnumDisplayName(DisplayName = "Super Admin")]
SuperAdmin = 0,
[EnumDisplayName(DisplayName = "Phoenix Admin")]
PhoenixAdmin = 1,
[EnumDisplayName(DisplayName = "Office Admin")]
OfficeAdmin = 2,
[EnumDisplayName(DisplayName = "Report User")]
ReportUser = 3,
[EnumDisplayName(DisplayName = "Billing User")]
BillingUser = 4
}
Output:

Another take on this:
class Program
{
//Example enum
public enum eFancyEnum
{
[Description("Obsolete")]
Yahoo,
[Description("I want food")]
Meow,
[Description("I want attention")]
Woof,
}
static void Main(string[] args)
{
//This is how you use it
Dictionary<eFancyEnum, string> myDictionary = typeof(eFancyEnum).ToDictionary<eFancyEnum>();
}
}
public static class EnumExtension
{
//Helper method to get description
public static string ToDescription<T>(this T en)
{
Type type = en.GetType();
MemberInfo[] memInfo = type.GetMember(en.ToString());
if (memInfo != null && memInfo.Length > 0)
{
object[] attrs = memInfo[0].GetCustomAttributes(typeof(DescriptionAttribute), false);
if (attrs != null && attrs.Length > 0)
return ((DescriptionAttribute)attrs[0]).Description;
}
return en.ToString();
}
//The actual extension method that builds your dictionary
public static Dictionary<T, string> ToDictionary<T>(this Type source) where T : struct, IConvertible
{
if(!source.IsEnum || typeof(T) != source)
{
throw new InvalidEnumArgumentException("BOOM");
}
Dictionary<T, string> retVal = new Dictionary<T,string>();
foreach (var item in Enum.GetValues(typeof(T)).Cast<T>())
{
retVal.Add(item, item.ToDescription());
}
return retVal;
}
}

Whenever I need an enumeration (a static list of known values) that need to have something more than just a mere integer value and a string counterpart, I end up using this Enumeration Utility class that essentially gives me java-like enumeration behavior.
So that would be my first option if I were on op's shoes as it would make it really trivial to achieve what he/she wants.
But, assuming this is not an option for op and she/he need to stick with C# enums, I would use a combination of both ehsan-sajjad and frank-j solutions:
Have an extension method to return the description of a given enum
item, which is pretty much what op had already;
Have a static helper method to return a dictionary of items and their respective descriptions for a given enum type.
Here is how I would implement this:
public static class EnumUtils
{
public static string GetDescription(this Enum enumVal)
{
var type = enumVal.GetType();
var memInfo = type.GetMember(enumVal.ToString());
var attributes = memInfo[0].GetCustomAttributes(typeof (DescriptionAttribute), false);
return (attributes.Length > 0) ? ((DescriptionAttribute) attributes[0]).Description : null;
}
public static Dictionary<TEnum, string> GetItemsWithDescrition<TEnum>()
{
var enumType = typeof(TEnum);
if (!enumType.IsEnum)
{
throw new InvalidOperationException("TEnum must be an enum type");
}
return Enum
.GetValues(enumType)
.Cast<TEnum>()
.ToDictionary(enumValue => enumValue, enumValue => GetDescription(enumValue as Enum));
}
}
And here is what the usage would look like:
public class EnumUtilsTests
{
public enum MyEnum
{
[Description("Um")]
One,
[Description("Dois")]
Two,
[Description("Tres")]
Three,
NoDescription
}
public void Should_get_enum_description()
{
MyEnum.One.GetDescription().ShouldBe("Um");
MyEnum.Two.GetDescription().ShouldBe("Dois");
MyEnum.Three.GetDescription().ShouldBe("Tres");
MyEnum.NoDescription.GetDescription().ShouldBe(null);
}
public void Should_get_all_enum_values_with_description()
{
var response = EnumUtils.GetItemsWithDescrition<MyEnum>();
response.ShouldContain(x => x.Key == MyEnum.One && x.Value == "Um");
response.ShouldContain(x => x.Key == MyEnum.Two && x.Value == "Dois");
response.ShouldContain(x => x.Key == MyEnum.Three && x.Value == "Tres");
response.ShouldContain(x => x.Key == MyEnum.NoDescription && x.Value == null);
}
}

Try replacing
.ToDictionary(k => k, v => v.GetAttributeOfType<DescriptionAttribute>().Description)
with
.Select(t => new { k = t, v = t.GetAttributeOfType<DescriptionAttribute>().Description)
.ToDictionary(s => s.k, s => s.v)
In your example, the wrong overload of ToDictionary() is being called.

How to get all descriptions of enum values with reflection?

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;
}
}
}

more elegant design about enum

I'm on learning for C#.
I heared C# is one of the most constructible language. so would you guys make my code more elegant and efficient?
public class ISO639
{
public enum ISO639Code
{
Afrikaans, //af
Albanian, //sq
Amharic, //am
...
Yiddish, //yi
Unknown
}
public static string GetISO639CodeString(ISO639.ISO639Code l)
{
switch (l)
{
case ISO639Code.English: return "en";
case ISO639Code.Japanese: return "ja";
...
case ISO639Code.Hebrew: return "he";
default: return "";
}
public static ISO639.ISO639Code GetISO39CodeValue(string s)
{
switch (s)
{
case "ko" : return ISO639Code.Korean;
case "en" : return ISO639Code.English;
...
case "hu" : return ISO639Code.Hungarian;
default: return ISO639Code.Unknown;
}
}
}
Here is a my class ISO639. This class provides enum for ISO639 code, but I need a type conversion on from ISO639 enum to plain string. (ex. ISO639.ISO639Code.Italian => "it"). I also need a type conversion from plain string to ISO639 enum. (ex. "it" => ISO639.ISO639Code.Italian).
Is there a more efficient coding style for that?

You can add standard System.ComponentModel.Description attribute to each enum entry and then read it.
public enum ISO639Code
{
[Description("af")]
Afrikaans
}
public static class EnumExtensions
{
// Extension method to read Description value
public static string GetDescription(this Enum currentEnum)
{
var fi = currentEnum.GetType().GetField(currentEnum.ToString());
var da = (DescriptionAttribute)Attribute.GetCustomAttribute(fi, typeof(DescriptionAttribute));
return da != null ? da.Description : currentEnum.ToString();
}
}
// **How-to read it**
ISO639Code isoCode = ISO639Code.Afrikaans;
// this will returns "af"
string isoDescription = isoCode.GetDescription();
EDIT:
string searchFor = "af";
ISO639Code foundEntry;
// Loop through all entries descriptions
var allEntries = Enum.GetValues(typeof(ISO639Code));
foreach (var entry in allEntries)
{
// If you will extract this as separate method and use it for search not only loop
// through the all entries - you can put here is yield return description
var currentEntry = ((ISO639Code)entry);
string description = currentEntry.GetDescription();
if (description == searchFor)
{
foundEntry = currentEntry;
break;
}
}

Sure. You can use attributes:
public enum ISO639Code
{
[CodeString("af")] Afrikaans,
[CodeString("sq")] Albanian,
}

Use dictionary, for example: new Dictionary<ISO639Code, string>.

I suggest you to use C# extension methods to enums, they allow you to add whatever logic you want.
For example, see http://pietschsoft.com/post/2008/07/c-enhance-enums-using-extension-methods.aspx

I'd simply store the information in a dictionary-like object. This way you can reference the name by key and get the value directly.

You have an enum:
public enum ISO639Code
{
Afrikaans = 1,
Albanian = 2,
Amharic = 3,
etc.
Create a database table:
ISO639Id int PK,
ISO639Code char(2)
Where the ISO639Id maps to the value of the enum.
In code you'd want a ISO630 Class containing Id and Code values read from the database.
(You can load this once and then cache it in memory.)
The beauty of this approach, is it can be easily extended so that if in future you wanted to store more pieces of information for each ISO639 code, you could simply add another field.

Look at System.Globailzation namespace. The functionality you require looks to be already implemented there. At worst you can see the architecture and technique applied in the .Net framework to solve a very similar problem.

Enumerations are really good to work in code, as they are really strongly typed and make refactoring easier.
Follow these steps:
Use attributes for whatever extra information you want to attach to an enum. Usually this is a simple Description attribute. Something like:
public enum IsoCodes
{
[Description("af")]
Africans = 0,
[Description("am")]
Americans = 1
}
Then write some extension methods to convert strings and integers to and from this enum:
public static string GetDescription(this Enum value)
{
var entries = value.ToString().Split(FlagEnumSeparatorCharacter);
var description = new string[entries.Length];
for (var i = 0; i < entries.Length; i++)
{
var fieldInfo = value.GetType().GetField(entries[i].Trim());
var attributes = fieldInfo.GetCustomAttributes(typeof(DescriptionAttribute), false) as DescriptionAttribute[];
description[i] = (attributes.Length > 0) ? attributes[0].Description : entries[i].Trim();
}
return String.Join(", ", description);
}
public static int GetValue(this Enum value)
{
return (int)value.GetType().GetField(value.ToString()).GetRawConstantValue();
}
public static T ToEnum<T>(this string value)
{
if (typeof(T).BaseType.Name != typeof(Enum).Name)
{
throw new Exception("Not an enum");
}
return (T)Enum.Parse(typeof(T), value, true);
}
public static T ToEnum<T>(this int value)
{
if (typeof(T).BaseType.Name != typeof(Enum).Name)
{
throw new Exception("Not an enum");
}
return (T)Enum.ToObject(typeof(T), value);
}
Now use your enums as you like.

I would go with having ISO639Code as class instead of enum:
public class ISO639Code
{
public string Value { get; set ; }
public string Code { get; set; }
public ISO639Code()
{
this.Value = "";
this.Code = "";
}
public ISO639Code(string value, string code)
: this()
{
this.Value = value;
this.Code = code;
}
public override bool Equals(object obj)
{
if (obj != null)
{
if (obj is string)
return obj.ToString().Equals(this.Value, StringComparison.CurrentCultureIgnoreCase);
if (obj is ISO639Code)
return ((ISO639Code)obj).Value.Equals(this.Value, StringComparison.CurrentCultureIgnoreCase);
}
return false;
}
public override int GetHashCode()
{
return this.Value.GetHashCode();
}
public override string ToString()
{
return this.Value;
}
}
Then have global List<ISO639Code> with all possible codes, and to find specific code based on code name or value, just search for this in the List.
Personally, I prefer this over tweaking the enum.

Generic Method Enum To String Conversion

I have seen lots of method to convert a string to an enum using generics but cannot find a neat way to convert an enum to string using generics.
What I mean is Pass an enum and a value and return the mapped name of the enum.
Any suggestions

How about:
enum E
{
A = 2,
B = 3
}
public static string GetLiteral<T>(object value)
{
return Enum.GetName(typeof(T), value);
}
static void Main(string[] args)
{
Console.WriteLine(GetLiteral<E>(2));
Console.WriteLine(GetLiteral<E>(3));
}

This works when you know the value, and type of the enum but you want to get the enum instance back that is matching value..
static T ConvertToEnum<T>(object value)
{
return (T) Enum.Parse(typeof(T), Enum.GetName(typeof(T), value));
}
static void Main(string[] args)
{
Gender g1 = ConvertToEnum<Gender>(0); //Male
Gender g2 = ConvertToEnum<Gender>(1); //Female
Gender g3 = ConvertToEnum<Gender>(2); //*BANG* exception
}

I would write a extension method to do so eg
using System.ComponentModel;
public enum StatusResult
{
[Description("Success")]
Success,
[Description("Failure...")]
Failure
}
public static class AttributesHelperExtension
{
public static string ToDescription(this Enum value)
{
DescriptionAttribute[] da = (DescriptionAttribute[])(value.GetType().GetField(value.ToString())).GetCustomAttributes(typeof(DescriptionAttribute), false);
return da.Length > 0 ? da[0].Description : value.ToString();
}
public static T ToEnum<T>(this string stringValue, T defaultValue)
{
foreach (T enumValue in Enum.GetValues(typeof(T)))
{
DescriptionAttribute[] da = (DescriptionAttribute[])(typeof(T).GetField(enumValue.ToString())).GetCustomAttributes(typeof(DescriptionAttribute), false);
if (da.Length > 0 && da[0].Description == stringValue)
return enumValue;
}
return defaultValue;
}
}
Now to call this use
string value = StatusResult.Failure.ToDescription();

I came across this method that I used to use a while ago.
It uses the Extensions, and should always return an enum
public static T ToEnum<T>(this string type, T defaultEnum)
{
T holder;
try
{
holder = (T)Enum.Parse(typeof(T), type);
}
catch
{
holder = defaultEnum;
}
return holder;
}

Get type name without any generics info

If I write:
var type = typeof(List<string>);
Console.WriteLine(type.Name);
It will write:
List`1
I want it to write just:
List
How can I do that?
Is there a smarter way to do it without having to use Substring or similar string manipulation functions?

No, it makes perfect sense for it to include the generic arity in the name - because it's part of what makes the name unique (along with assembly and namespace, of course).
Put it this way: System.Nullable and System.Nullable<T> are very different types. It's not expected that you'd want to confuse the two... so if you want to lose information, you're going to have to work to do it. It's not very hard, of course, and can be put in a helper method:
public static string GetNameWithoutGenericArity(this Type t)
{
string name = t.Name;
int index = name.IndexOf('`');
return index == -1 ? name : name.Substring(0, index);
}
Then:
var type = typeof(List<string>);
Console.WriteLine(type.GetNameWithoutGenericArity());

No, it doesn't, because the "generic-type-string" is part of the name of type.

If someone is interested, I created some extensionmethods for this problem that create a more "readable" string
it produces something like
List[string]
outer.inner[other.whatever]
IEnumerable[T0]
Dictionary[string:int]
Test here
public static class TypeEx
{
public static string GetTypeName(this Type type)
{
if (type == null)
throw new ArgumentNullException(nameof(type));
if (!type.IsGenericType)
return type.GetNestedTypeName();
StringBuilder stringBuilder = new StringBuilder();
_buildClassNameRecursiv(type, stringBuilder);
return stringBuilder.ToString();
}
private static void _buildClassNameRecursiv(Type type, StringBuilder classNameBuilder, int genericParameterIndex = 0)
{
if (type.IsGenericParameter)
classNameBuilder.AppendFormat("T{0}", genericParameterIndex + 1);
else if (type.IsGenericType)
{
classNameBuilder.Append(GetNestedTypeName(type) + "[");
int subIndex = 0;
foreach (Type genericTypeArgument in type.GetGenericArguments())
{
if (subIndex > 0)
classNameBuilder.Append(":");
_buildClassNameRecursiv(genericTypeArgument, classNameBuilder, subIndex++);
}
classNameBuilder.Append("]");
}
else
classNameBuilder.Append(type.GetNestedTypeName());
}
public static string GetNestedTypeName(this Type type)
{
if (type == null)
throw new ArgumentNullException(nameof(type));
if (!type.IsNested)
return type.Name;
StringBuilder nestedName = new StringBuilder();
while(type != null)
{
if(nestedName.Length>0)
nestedName.Insert(0,'.');
nestedName.Insert(0, _getTypeName(type));
type = type.DeclaringType;
}
return nestedName.ToString();
}
private static string _getTypeName(Type type)
{
return type.IsGenericType ? type.Name.Split('`')[0]: type.Name;
}
}

static void Main(string[] args)
{
Console.WriteLine(WhatIsMyType<IEnumerable<string>>());
Console.WriteLine(WhatIsMyType<List<int>>());
Console.WriteLine(WhatIsMyType<IList<int>>());
Console.WriteLine(WhatIsMyType<List<ContentBlob>>());
Console.WriteLine(WhatIsMyType<int[]>());
Console.WriteLine(WhatIsMyType<ContentBlob>());
Console.WriteLine(WhatIsMyType<Dictionary<string, Dictionary<int, int>>>());
}
public static string WhatIsMyType<T>()
{
return typeof(T).NameWithGenerics();
}
public static string NameWithGenerics(this Type type)
{
if (type == null)
throw new ArgumentNullException(nameof(type));
if (type.IsArray)
return $"{type.GetElementType()?.Name}[]";
if (!type.IsGenericType)
return type.Name;
var name = type.GetGenericTypeDefinition().Name;
var index = name.IndexOf('`');
var newName = index == -1 ? name : name.Substring(0, index);
var list = type.GetGenericArguments().Select(NameWithGenerics).ToList();
return $"{newName}<{string.Join(",", list)}>";
}
Example output:
IEnumerable<String>
List<Int32>
IList<Int32>
List<ContentBlob>
Int32[]
ContentBlob
Dictionary<String,Dictionary<Int32,Int32>>

Here's the code from this answer inside a static class and namespace for easier copy-and-pasting.
Also, there's another extension method to get the type its namespace.
using System;
namespace TODO
{
public static class TypeExtensions
{
/// <summary>
/// From: https://stackoverflow.com/a/6386234/569302
/// </summary>
public static string GetNameWithoutGenericArity(this Type t)
{
string name = t.Name;
int index = name.IndexOf('`');
return index == -1 ? name : name.Substring(0, index);
}
public static string GetFullNameWithoutGenericArity(this Type t)
{
var result = $"{t.Namespace}.{t.GetNameWithoutGenericArity()}";
return result;
}
}
}

The easiest way I can think of as of C#6(I think) you can do the following:
public static void Main(string[] args)
{
Console.WriteLine(nameof(List<int>));
Console.WriteLine(nameof(Dictionary<int, int>));
}
This will print:
List
Dictionary