I need to get working validation of the custom ASP.NET MVC helper.
Helper
public static class AutocompleteHelper
{
public static MvcHtmlString AutocompleteFor<TModel, TValue>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TValue>> expression, string actionUrl)
{
return CreateAutocomplete(helper, expression, actionUrl, null, null);
}
public static MvcHtmlString AutocompleteFor<TModel, TValue>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TValue>> expression, string actionUrl, bool? isRequired, string placeholder)
{
return CreateAutocomplete(helper, expression, actionUrl, placeholder, isRequired);
}
private static MvcHtmlString CreateAutocomplete<TModel, TValue>(HtmlHelper<TModel> helper, Expression<Func<TModel, TValue>> expression, string actionUrl, string placeholder, bool? isRequired)
{
var attributes = new Dictionary<string, object>
{
{ "data-autocomplete", true },
{ "data-action", actionUrl }
};
if (!string.IsNullOrWhiteSpace(placeholder))
{
attributes.Add("placeholder", placeholder);
}
if (isRequired.HasValue && isRequired.Value)
{
attributes.Add("required", "required");
}
attributes.Add("class", "form-control formControlAutocomplete");
attributes.Add("maxlength", "45");
Func<TModel, TValue> method = expression.Compile();
var value = method((TModel)helper.ViewData.Model);
var baseProperty = ((MemberExpression)expression.Body).Member.Name;
var hidden = helper.Hidden(baseProperty, value);
attributes.Add("data-value-name", baseProperty);
var automcompleteName = baseProperty + "_autocomplete";
var textBox = helper.TextBox(automcompleteName, null, string.Empty, attributes);
var builder = new StringBuilder();
builder.AppendLine(hidden.ToHtmlString());
builder.AppendLine(textBox.ToHtmlString());
return new MvcHtmlString(builder.ToString());
}
}
HTML
#Html.AutocompleteFor(x => x.ProductUID, Url.Action("AutocompleteProducts", "Requisition"), true, "Start typing Product name...")
#Html.ValidationMessageFor(x => x.ProductUID)
I seems like validating but no message appears.
Any clue?
The name of your text field is ProductUID_autocomplete but your ValidationMessageFor which is supposed to display the error message is bound to ProductUID.
So make sure that you are binding your error message to the same property:
#Html.ValidationMessage("ProductUID_autocomplete")
It appears that whatever custom logic you might have to validate this field is injecting the error under the ProductUID_autocomplete key in the ModelState.
This being said, why not just invoke the ValidationMessage helper inside your custom helper? This way you will have less things to type in your view and the logic with those names being suffixed with _autocomplete will stay inside the helper only.
Related
In my razor view I am using an HTML Helper Extension method in order to use the Display Name attribute of my Model Property to display a placeholder value in a textbox. See example below.
My Helper Extension Method:
public static MvcHtmlString TextBoxPlaceHolderFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, IDictionary<string, object> htmlAttributes)
{
ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);
string htmlFieldName = ExpressionHelper.GetExpressionText(expression);
string labelText = metadata.DisplayName ?? metadata.PropertyName ?? htmlFieldName.Split('.').Last();
if (!String.IsNullOrEmpty(labelText))
{
if (htmlAttributes == null)
{
htmlAttributes = new Dictionary<string, object>();
}
htmlAttributes.Add("placeholder", labelText);
}
return html.TextBoxFor(expression, htmlAttributes);
}
My Model Property:
[Display(Name = "First Name", Description = "Enter Display Name")]
public string FirstName { get; set; }
Current Outcome:
Display Name of property displays inside the field as a placeholder.
However, sometimes I might want to use another property on the model for the placeholder text (like the Description property in the model above).
How can I make it so a Model data annotation property can be passed in the razor view and the the placeholder uses the value of that property instead?
Example code of what I want is below.
The razor view with meta-data property passed:
#Html.TextBoxPlaceHolderFor(model => model.FirstName, new { #class = "form-control" }, MODELMETADATAPROPERTY HERE)
The HTML Helper Extension (what I imagine the code would do, probably need to use reflection or something?)
public static MvcHtmlString TextBoxPlaceHolderFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, IDictionary<string, object> htmlAttributes, MODELMETADATAPROPERTY HERE)
{
ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);
string htmlFieldName = ExpressionHelper.GetExpressionText(expression);
string labelText = metadata.MODELMETADATAPROPERTY HERE;
if (!String.IsNullOrEmpty(labelText))
{
if (htmlAttributes == null)
{
htmlAttributes = new Dictionary<string, object>();
}
htmlAttributes.Add("placeholder", labelText);
}
return html.TextBoxFor(expression, htmlAttributes);
}
you can use the following
public static MvcHtmlString TextBoxPlaceHolderFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, IDictionary<string, object> htmlAttributes)
{
ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);
string htmlFieldName = ExpressionHelper.GetExpressionText(expression);
string labelText = metadata.DisplayName ?? Proper(metadata.PropertyName?? htmlFieldName.Split('.').Last());
if (!String.IsNullOrEmpty(labelText))
{
if (htmlAttributes == null)
{
htmlAttributes = new Dictionary<string, object>();
}
htmlAttributes.Add("placeholder", modeldata.Description??Proper(metadata.PropertyName?? htmlFieldName.Split('.').Last())); // to get the description value
}
return html.TextBoxFor(expression, labelText);
}
// this function will convert FullName to Full Name with space
private static string Proper(string value)
{
var newValue = Regex.Replace(value, "([a-z])([A-Z])", "$1 $2");
return newValue;
}
As far as I know there are no (extension) methods in the HtmlHelper class that can generate a HTML5 input element of type range so I am trying to implement my own by extending the HtmlHelper class:
public static class MvcHtmlHelper
{
public static HtmlString RangeFor<TModel, TProperty>
(this HtmlHelper<TModel> htmlHelper,
Expression<Func<TModel, TProperty>> expression,
object htmlAttributes)
{
var name = ExpressionHelper.GetExpressionText(expression);
var metadata = ModelMetadata.FromLambdaExpression(expression,
htmlHelper.ViewData);
//var min = (string)((ViewDataDictionary<TModel>)htmlAttributes)["min"];
//var max = (string)((ViewDataDictionary<TModel>)htmlAttributes)["max"];
//var value = (string)((ViewDataDictionary<TModel>)htmlAttributes)["value"];
return Range(htmlHelper, min, max, value);
}
public static HtmlString Range(this HtmlHelper htmlHelper,
string name, string min, string max, string value = "0")
{
var builder = new TagBuilder("input");
builder.Attributes["type"] = "range";
builder.Attributes["name"] = name;
builder.Attributes["min"] = min;
builder.Attributes["max"] = max;
builder.Attributes["value"] = value;
return new HtmlString(builder.ToString(TagRenderMode.SelfClosing));
}
}
I am trying to emulate the existing TextBoxFor extension method which allows callers to specify extra htmlAttributes via an anonymous object. However I am getting an InvalidCastException on the commented lines above.
Can anyone point me to the correct way of obtaining the values from the anonymous htmlAttributes object (similar to how TextBoxFor handles htmlAttributes?
InputExtensions.TextBoxFor handles attributes the following way:
public static MvcHtmlString TextBoxFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, object htmlAttributes)
{
return InputExtensions.TextBoxFor<TModel, TProperty>(htmlHelper, expression, (IDictionary<string, object>) HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
}
So you have to create attributes dictionary from anomymous object before you use it
I'm using right now this code to implement a RadioButtonList using MVC4.
And as you can see, that function does not have htmlAttributes parameter. So I'd like to add it and here is the problem. Check please that the htmlAttributes for RadioButtonFor() is occupied by the id.
I was trying to add it but throws me errors because the id already exists for the loop.
public static class HtmlExtensions
{
public static MvcHtmlString RadioButtonForSelectList<TModel, TProperty>(
this HtmlHelper<TModel> htmlHelper,
Expression<Func<TModel, TProperty>> expression,
IEnumerable<SelectListItem> listOfValues)
{
return htmlHelper.RadioButtonForSelectList(expression, listOfValues, null);
}
public static MvcHtmlString RadioButtonForSelectList<TModel, TProperty>(
this HtmlHelper<TModel> htmlHelper,
Expression<Func<TModel, TProperty>> expression,
IEnumerable<SelectListItem> listOfValues,
object htmlAttributes)
{
return htmlHelper.RadioButtonForSelectList(expression, listOfValues, new RouteValueDictionary(htmlAttributes));
}
public static MvcHtmlString RadioButtonForSelectList<TModel, TProperty>(
this HtmlHelper<TModel> htmlHelper,
Expression<Func<TModel, TProperty>> expression,
IEnumerable<SelectListItem> listOfValues,
IDictionary<string, object> htmlAttributes)
{
var metaData = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
var sb = new StringBuilder();
if (listOfValues != null)
{
foreach (SelectListItem item in listOfValues)
{
var id = string.Format(
"{0}_{1}",
metaData.PropertyName,
item.Value
);
var radio = htmlHelper.RadioButtonFor(expression, item.Value, new { id = id }).ToHtmlString();
sb.AppendFormat(
"{0}<label for=\"{1}\">{2}</label>",
radio,
id,
HttpUtility.HtmlEncode(item.Text)
);
}
}
return MvcHtmlString.Create(sb.ToString());
}
}
In the third method, it looks like the html attributes being passed to the radion button being created is new { id = id }. Try to replace that with the parameter from the method.
UPDATED
Include id in the html attributes and assign a new value to id in each loop iteration.
if (listOfValues != null)
{
if (!htmlAttributes.ContainsKey("id"))
{
htmlAttributes.Add("id", null);
}
foreach (SelectListItem item in listOfValues)
{
var id = string.Format(
"{0}_{1}",
metaData.PropertyName,
item.Value
);
htmlAttributes["id"] = id;
var radio = htmlHelper.RadioButtonFor(expression, item.Value, htmlAttributes).ToHtmlString();
sb.AppendFormat(
"{0}<label for=\"{1}\">{2}</label>",
radio,
id,
HttpUtility.HtmlEncode(item.Text)
);
}
}
This is different approach to translation of page. It is not meant to be localization.
I created class TransModel which all my ViewModels are inheriting from.
This class fetches string pairs relevant for current ViewModel from database and stores them in "labels" Dictionary. Key for that pair is the value of string here "User Name" and value is translated value.
[Display(Name = "User Name")]
public string UserName { get; set; }
Instead of using Html.LabelFor in View I use extension of it call it TransLabelFor
public static MvcHtmlString TransLabelFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression,TransModel model)
{
ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);
string trans = "";
model.labels.TryGetValue(metadata.DisplayName, out trans);
if (trans == null)
{
trans = metadata.DisplayName;
}
return MvcHtmlString.Create(String.Format("<label for='{0}'>{1}</label>", metadata.DisplayName, trans));
}
Now I want to replace what I return by it. I want the original tag as returned by this:
MvcHtmlString originalTag = System.Web.Mvc.Html.LabelExtensions.LabelFor(html, expression);
but with my translation.
Are there any neat ways of doing it instead of string find/replace? I don't like that I have to pass Model around either, any better ideas?
Or "improvement" to your solution (also including reflection, but this will avoid to put TransModel in your helpers)
public static IHtmlString TransLabelFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression)
{
var metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);
var htmlFieldName = ExpressionHelper.GetExpressionText(expression);
var modelType = typeof (TModel);
var resolvedLabelText = metadata.DisplayName ?? metadata.PropertyName;
if (String.IsNullOrEmpty(resolvedLabelText))
return MvcHtmlString.Empty;
var labelProperty = modelType.GetProperty("labels");
if (labelProperty != null)
{
var labels = labelProperty.GetValue(html.ViewData.Model, null) as Dictionary<string, string>;
if (labels != null && labels.ContainsKey(resolvedLabelText))
resolvedLabelText = labels[resolvedLabelText];
}
var tag = new TagBuilder("label");
tag.Attributes.Add("for", TagBuilder.CreateSanitizedId(html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(htmlFieldName)));
tag.SetInnerText(resolvedLabelText);
return MvcHtmlString.Create(tag.ToString());
}
but this will mean you'll have to change all your LabelFor to TransLableFor (string replace in all solution) : but at least you don't have to add a "TransModel" during the replacement.
When using an HTML Helper, what is the best method to set an attribute based on a condition. For example
<%if (Page.User.IsInRole("administrator")) {%>
<%=Html.TextBoxFor(m => m.FirstName, new {#class='contactDetails'}%>
<%} else {%>
<%=Html.TextBoxFor(m => m.FirstName, new {#class='contactDetails', disabled = true}%>
<%}%>
There must be a better way to programmatically add just one additional KeyPair to the anonymous type? Can't use
new { .... disabled = Page.User.IsInRole("administrator") ... }
as the browser takes any disabled attribute value as making the input disabled
I could suggest you to use mvccontrib.FluentHtml.
You can do something like this
<%=this.TextBox(m=>m.FirstNam ).Disabled(Page.User.IsInRole("administrator"))%>
It works for me as well...
<%: Html.DropDownList("SportID", (SelectList)ViewData["SportsSelectList"], "-- Select --", new { #disabled = "disabled", #readonly = "readonly" })%>
<%= Html.CheckBoxFor(model => model.IsActive, new { #disabled = "disabled", #readonly = "readonly" })%>
Page.User.IsInRole("administrator") ? null : new { disabled = "disabled" }
Using #SLaks suggestion to use an Extension method, and using Jeremiah Clark's example Extension method I've written an extension method so I can now do
Html.TextBoxFor(m => m.FirstName,new{class='contactDetails', ...},Page.User.IsInRole("administrator"));
Not Sure if there's a better method though
public static class InputExtensions
{
public static IDictionary<string, object> TurnObjectIntoDictionary(object data)
{
var attr = BindingFlags.Public | BindingFlags.Instance;
var dict = new Dictionary<string, object>();
if (data == null)
return dict;
foreach (var property in data.GetType().GetProperties(attr))
{
if (property.CanRead)
{
dict.Add(property.Name, property.GetValue(data, null));
}
}
return dict;
}
public static MvcHtmlString TextBoxFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, object htmlAttributes, bool disabled)
{
IDictionary<string, object> values = TurnObjectIntoDictionary(htmlAttributes);
if (disabled)
values.Add("disabled","true");
return htmlHelper.TextBoxFor(expression, values);
}
public static MvcHtmlString TextAreaFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, object htmlAttributes, bool disabled)
{
IDictionary<string, object> values = TurnObjectIntoDictionary(htmlAttributes);
if (disabled)
values.Add("disabled", "true");
return htmlHelper.TextAreaFor(expression, values);
}
public static MvcHtmlString CheckBoxFor<TModel>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, bool>> expression, object htmlAttributes, bool disabled)
{
IDictionary<string, object> values = TurnObjectIntoDictionary(htmlAttributes);
if (disabled)
values.Add("disabled", "true");
return htmlHelper.CheckBoxFor(expression, values);
}
}
You'll need to pass a Dictionary<string, object>, and add the disabled key inside an if statement.
I recommend making an overload of the extension method that takes a bool disabled parameter and adds it to a RouteValueDictionary created from the attributes parameter if it's true. (You could also remove the disabled entry from the RouteValueDictionary if it's false, and not take another parameter)
You may also define this param that way:
Page.User.IsInRole("administrator")
? (object)new { #class='contactDetails'}
: (object)new { #class='contactDetails', disabled = true}
You may want to consider writing your own HtmlHelper Extension class with a new TextBox method:
public static class HtmlHelperExtensions
{
public static MvcHtmlString TextBoxFor(this HtmlHelper htmlHelper, Expression<Func<TModel, TProperty>> expression, string cssClass, bool disabled)
{
return disabled
? Html.TextBoxFor(expression, new {#class=cssClass, disabled="disabled"})
: Html.TextBoxFor(expression, new {#class=cssClass})
}
}
now (if this new class is in the same namespace, or you've imported the new namespace to your page header, or in the pages section of the web.config) you can do this on your aspx page:
<%=Html.TextBoxFor(m => m.FirstName, "contactDetails", Page.User.IsInRole("administrator")) %>
Created an extension method on Object that will create a copy of the input object excluding any properties that are null, and return it all as dictionary that makes it easily used in MVC HtmlHelpers:
public static Dictionary<string, object> StripAnonymousNulls(this object attributes)
{
var ret = new Dictionary<string, object>();
foreach (var prop in attributes.GetType().GetProperties())
{
var val = prop.GetValue(attributes, null);
if (val != null)
ret.Add(prop.Name, val);
}
return ret;
}
Not sure about performance implications of reflecting through properties twice, and don't like the name of the extension method much, but it seems to do the job well ...
new {
#class = "contactDetails",
disabled = Page.User.IsInRole("administrator") ? "true" : null
}.StripAnonymousNulls()