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Html.Labelfor use DisplayName object not property

For this view model:

public class ParentViewModel
{
    public object ChildViewModel { get; set; }
}

If I use Html.LabelForas follows:

@Html.LabelFor(model => model.ChildViewModel)

I would get this conclusion:

<label for="Model_ChildViewModel">ChildViewModel</label>

What I really want, but for the generated label, use the attribute DisplayNameapplied to the EG object

[DisplayName("My Custom Label")]
public class ChildViewModel
{
}

with output:

<label for="Model_ChildViewModel">My Custom Label</label>

I understand that a method Html.LabelForaccepts an expression that expects a property, and it will look for an attribute DisplayNamefor that property, not the object itself.

I created an Html helper method to achieve what I want it to look like this:

public static IHtmlString CreateLabel<TModel>(this HtmlHelper html, Func<TModel, object> func) 
    where TModel : class
    {
        TagBuilder tb = new TagBuilder("label");

        var model = html.ViewData.Model as TModel;
        if (model != null)
        {
            object obj = func(model);
            if (obj != null)
            {
                var attribute = obj.GetType().GetCustomAttributes(
                    typeof(DisplayNameAttribute), true)
                    .FirstOrDefault() as DisplayNameAttribute;

                if (attribute != null)
                {
                    tb.InnerHtml = attribute.DisplayName;
                    return MvcHtmlString.Create(tb.ToString());
                }
                else
                {
                    tb.InnerHtml = obj.ToString();
                    return MvcHtmlString.Create(tb.ToString());
                }
            }
        }

        tb.InnerHtml = html.ViewData.Model.ToString();
        return MvcHtmlString.Create(tb.ToString());
    }

Instead of accepting the expression, my helper accepts Func<TModel, object>which returns the object that I want to check for the attribute DisplayName.

, , , :

@Html.CreateLabel(model => model.ChildObject)

:

The type arguments for method 'CreateLabel<TModel>(this HtmlHelper,
Func<TModel, object>) cannot be inferred from usage. Try specifying
the arguments explicitly.'

:

 @{ Html.CreateLabel<ChildViewModel>(model => model.ChildObject); }

. , , .

, :

  • , ?
  • , ?
  • Html-, , ? , , .

, , . , MVC . TagBuilder, , <legend></legend>. . .

public static IHtmlString LegendTextFor<TModel, TObject>(this HtmlHelper<TModel> html, Expression<Func<TModel, TObject>> expression)
{
    return LegendTextHelper(html,
        ModelMetadata.FromLambdaExpression(expression, html.ViewData),
        ExpressionHelper.GetExpressionText(expression),
        expression.Compile().Invoke(html.ViewData.Model));
}

private static IHtmlString LegendTextHelper<TModel, TObject>(this HtmlHelper<TModel> html, ModelMetadata metadata, string htmlFieldName, TObject value)
{
    string resolvedLabelText = metadata.DisplayName ?? value.GetDisplayName() ?? metadata.PropertyName ?? htmlFieldName.Split('.').Last();

    if (String.IsNullOrEmpty(resolvedLabelText))
        return MvcHtmlString.Empty;

    return MvcHtmlString.Create(resolvedLabelText);
}

private static string GetDisplayName<T>(this T obj)
{
    if (obj != null)
    {
        var attribute = obj.GetType()
            .GetCustomAttributes(typeof(DisplayNameAttribute), false)
            .Cast<DisplayNameAttribute>()
            .FirstOrDefault();

        return attribute != null ? attribute.DisplayName : null;
    }
    else
    {
        return null;
    }
}
+5
1

Html , , :

Html :

public static class HtmlHelperExtensions
{

    public static MvcHtmlString LabelForCustom<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression)
    {
        ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);

        string customDisplayName = null;

       var value = expression.Compile().Invoke(html.ViewData.Model);

       if (value != null)
       {
          var attribute = value.GetType().GetCustomAttributes(typeof(DisplayNameAttribute), false)
           .Cast<DisplayNameAttribute>()
           .FirstOrDefault();

           customDisplayName = attribute != null ? attribute.DisplayName : null;
       }

         string htmlFieldName = ExpressionHelper.GetExpressionText(expression);
        string labelText = metadata.DisplayName ?? customDisplayName ?? metadata.PropertyName ?? htmlFieldName.Split('.').Last();
        if (String.IsNullOrEmpty(labelText))
        {
            return MvcHtmlString.Empty;
        }

        TagBuilder tag = new TagBuilder("label");
         tag.Attributes.Add("for", html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldId(htmlFieldName));
        tag.SetInnerText(labelText);
        return MvcHtmlString.Create(tag.ToString(TagRenderMode.Normal));
    }
}

:

public class Parent
{
    public object Child { get; set; }
}

[DisplayName("yo")]
public class Child 
{
   public int Id { get; set; }
}

:

@Html.LabelForCustom(m => m.Child)  @*prints yo*@
+2

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