How do I display the DisplayAttribute.Description attribute value?

user_10932 0
Viewed 51306

I have a model class, with a property like this:

[Display(Name = "Phone", Description="Hello World!")]
public string Phone1 { get; set; }

Displaying a label and rendering a textbox for input in my view is pretty easy:

@Html.LabelFor(model => model.Organization.Phone1)
@Html.EditorFor(model => model.Organization.Phone1)
@Html.ValidationMessageFor(model => model.Organization.Phone1)

But how do I render the value of the Description annotation attribute, i.e. "Hello World!"??

asp.net-mvc asp.net c#
13 Answers

If anyone is wondering how to use the accepted answer

1- In your solution explorer > Add new folder > name it"Helpers" for example
2- Add a new class, name it "CustomHtmlHelpers" for example
3- Paste the code : 

public static class MvcHtmlHelpers
{
    public static string DescriptionFor<TModel, TValue>(this HtmlHelper<TModel> self, Expression<Func<TModel, TValue>> expression)
    {
        var metadata = ModelMetadata.FromLambdaExpression(expression, self.ViewData);
        var description = metadata.Description;

        return string.IsNullOrWhiteSpace(description) ? "" : description;
    }
}

4- In your model or viewModel using it this: 

[Display(Name = "User Name", Description = "Enter your User Name")]
public string FullName { get; set; }

5- In your Razor view, after the @model, type this line 

@using YOUR_PROJECT.Helpers

6- Display the description like this: 

@Html.DescriptionFor(m => m.FullName)

7- You may want to use the description to display text in the input placeholder:

@Html.DisplayNameFor(m => m.FullName)
@Html.TextBoxFor(m => m.FullName, new { @class = "form-control", placeholder = Html.DescriptionFor(m => m.FullName) })

Thanks

user_15942740

Here is an updated version for ASP.NET Core 3.1 and 5:

public static class HtmlExtensions
{
    public static IHtmlContent DescriptionFor<TModel, TValue>(this IHtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression)
    {
        if (html == null) throw new ArgumentNullException(nameof(html));
        if (expression == null) throw new ArgumentNullException(nameof(expression));

        var expressionProvider = html.ViewContext?.HttpContext?.RequestServices?.GetService<ModelExpressionProvider>()
            ?? new ModelExpressionProvider(html.MetadataProvider);
        var modelExpression = expressionProvider.CreateModelExpression(html.ViewData, expression);

        return new HtmlString(modelExpression.Metadata.Description);
    }
}

We have to go via ModelExpressionProvider now that ExpressionMetadataProvider is marked internal.

ModelExpressionProvider.CreateModelExpression() calls ExpressionMetadataProvider.FromLambdaExpression() internally anyway:

https://github.com/aspnet/Mvc/blob/04ce6cae44fb0cb11470c21769d41e3f8088e8aa/src/Microsoft.AspNetCore.Mvc.ViewFeatures/ModelExpressionProvider.cs#L42

user_22663450

HANDL's answer, updated for ASP.NET Core 2.0

using System;
using System.Linq.Expressions;
using Microsoft.AspNetCore.Html;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewFeatures.Internal;

public static class HtmlExtensions
{
    public static IHtmlContent DescriptionFor<TModel, TValue>(this IHtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression)
    {
        if (html == null) throw new ArgumentNullException(nameof(html));
        if (expression == null) throw new ArgumentNullException(nameof(expression));

        var modelExplorer = ExpressionMetadataProvider.FromLambdaExpression(expression, html.ViewData, html.MetadataProvider);
        if (modelExplorer == null) throw new InvalidOperationException($"Failed to get model explorer for {ExpressionHelper.GetExpressionText(expression)}");

        return new HtmlString(modelExplorer.Metadata.Description);
    }
}
user_1806770

You can always create your own custom extension like this:

    public static MvcHtmlString ToolTipLabel (string resourceKey, string text, bool isRequired, string labelFor = "", string labelId = "",string className="")
    {
        string tooltip = string.Empty;

        StringBuilder sb = new StringBuilder();

        if (!string.IsNullOrEmpty(resourceKey))
        {
            var resources = GetAllResourceValues();

            if (resources.ContainsKey(resourceKey))
            {
                tooltip = resources[resourceKey].Value;
            }
        }

        sb.Append("<label");

        if (!string.IsNullOrEmpty(labelFor))
        {
            sb.AppendFormat(" for=\"{0}\"", labelFor);
        }

        if (!string.IsNullOrEmpty(labelId))
        {
            sb.AppendFormat(" Id=\"{0}\"", labelId);
        }

        if (!string.IsNullOrEmpty(className))
        {
            sb.AppendFormat(" class=\"{0}\"", className);
        }

        if (!string.IsNullOrEmpty(tooltip))
        {

            sb.AppendFormat(" data-toggle='tooltip' data-placement='auto left' title=\"{0}\"",tooltip);

        }
        if (isRequired)
        {
            sb.AppendFormat("><em class='required'>*</em> {0} </label></br>", text);
        }
        else
        {
            sb.AppendFormat(">{0}</label></br>", text);
        }
        return MvcHtmlString.Create(sb.ToString());
    }

and can get it in view like this:

@HtmlExtension.ToolTipLabel(" "," ",true," "," "," ")
user_85631360
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