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Created November 20, 2011 03:29
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Extension methods for ASP.NET MVC3 that provide helpers for getting display names from IEnumerable models.
using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Web.Mvc;
namespace Web.Extensions
{
public static class HtmlHelperDisplayNameExtensions
{
/// <summary>
/// Get the Display Name for a model.
/// </summary>
/// <typeparam name="TModel">The model's Type</typeparam>
/// <param name="helper">The HTML Helper for the model.</param>
/// <returns>Returns the DisplayName for the model.</returns>
/// <remarks>
/// Use the DisplayNameAttribute on your model to assign the name to be returned.
/// Unfortunately we can not use the better/newer DisplayAttribute to specify the name
/// because Microsoft marked it to only be used on properties, not on classes.
///
/// Use: @Html.DisplayNameFor()
/// </remarks>
public static MvcHtmlString DisplayNameFor<TModel>(this HtmlHelper<IEnumerable<TModel>> helper)
{
var metadata = ModelMetadataProviders.Current.GetMetadataForType(() => Activator.CreateInstance<TModel>(), typeof(TModel));
return new MvcHtmlString(metadata.DisplayName ?? typeof(TModel).Name);
}
/// <summary>
/// Gets the Display Name for a property of a type being handled by an IEnumerable.
/// </summary>
/// <typeparam name="TModel"></typeparam>
/// <typeparam name="TClass"></typeparam>
/// <typeparam name="TProperty"></typeparam>
/// <param name="helper">Html helper for the IEnumerable&lt;TClass&gt;</param>
/// <param name="model">An instance of an IEnumerable. Its generic parameter is the type we want the display name for.</param>
/// <param name="expression">An expression indicating the property to get the display name for.</param>
/// <returns>The display name for the property, or the property name if no display name is provided.</returns>
/// <remarks>
/// Use the DisplayAttribute to set the display name for the property.
/// This is designed to be used in a View that takes an IEnumerable model.
///
/// View: @model = IEnumerable&lt;SomeClass&gt;
/// Use: @Html.DisplayNameFor(Model, someclass => someclass.SomeProperty)
/// </remarks>
public static MvcHtmlString DisplayNameFor<TModel, TClass, TProperty>(this HtmlHelper<TModel> helper, IEnumerable<TClass> model, Expression<Func<TClass, TProperty>> expression)
{
var name = GetFullNameFromExpression(helper, expression);
return GetDisplayNameForProperty<TClass>(name);
}
/// <summary>
/// Gets the Display Name for a property of a type being handled by an IEnumerable.
/// </summary>
/// <typeparam name="TModel"></typeparam>
/// <typeparam name="TProperty"></typeparam>
/// <param name="helper">Html helper for the IEnumerable&lt;T&gt;</param>
/// <param name="expression">An expression indicating the property to get the display name for.</param>
/// <returns>The display name for the property, or the property name if no display name is provided.</returns>
/// <remarks>
/// Use the DisplayAttribute to set the display name for the property.
/// This is designed to be used in a View that takes an IEnumerable model.
///
/// View: @model = IEnumerable&lt;SomeClass&gt;
/// Use: @Html.DisplayNameFor(someclass => someclass.SomeProperty)
/// </remarks>
public static MvcHtmlString DisplayNameFor<TModel, TProperty>(this HtmlHelper<IEnumerable<TModel>> helper, Expression<Func<TModel, TProperty>> expression)
{
var name = GetFullNameFromExpression(helper, expression);
return GetDisplayNameForProperty<TModel>(name);
}
private static string GetFullNameFromExpression<TModel, TClass, TProperty>(HtmlHelper<TModel> helper, Expression<Func<TClass, TProperty>> expression)
{
var name = ExpressionHelper.GetExpressionText(expression);
name = helper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(name);
return name;
}
private static MvcHtmlString GetDisplayNameForProperty<TClass>(string propertyName)
{
var metadata = ModelMetadataProviders.Current.GetMetadataForProperty(() => Activator.CreateInstance<TClass>(), typeof(TClass), propertyName);
return new MvcHtmlString(metadata.DisplayName ?? typeof(TClass).Name);
}
}
}
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