Extract Display name and description Attribute from within a HTML helper

Question

I am building a custom HTML.LabelFor helper that looks like this :

public static MvcHtmlString LabelFor(this HtmlHelper<         


        

Answer 1

Disclaimer: The following works only with ASP.NET MVC 3 (see the update at the bottom if you are using previous versions)

Assuming the following model:

public class MyViewModel
{
    [Display(Description = "some description", Name = "some name")]
    public string SomeProperty { get; set; }
}

And the following view:

<%= Html.LabelFor(x => x.SomeProperty, true) %>

Inside your custom helper you could fetch this information from the metadata:

public static MvcHtmlString LabelFor(
    this HtmlHelper self, 
    Expression> expression, 
    bool showToolTip
)
{
    var metadata = ModelMetadata.FromLambdaExpression(expression, self.ViewData);
    var description = metadata.Description; // will equal "some description"
    var name = metadata.DisplayName; // will equal "some name"
    // TODO: do something with the name and the description
    ...
}

Remark: Having [DisplayName("foo")] and [Display(Name = "bar")] on the same model property is redundant and the name used in the [Display] attribute has precedence in metadata.DisplayName.

---

UPDATE:

My previous answer won't work with ASP.NET MVC 2.0. There are a couples of properties that it is not possible to fill by default with DataAnnotations in .NET 3.5, and Description is one of them. To achieve this in ASP.NET MVC 2.0 you could use a custom model metadata provider:

public class DisplayMetaDataProvider : DataAnnotationsModelMetadataProvider
{
    protected override ModelMetadata CreateMetadata(
        IEnumerable attributes, 
        Type containerType,
        Func