MVC extension DataAnnotationsModelMetadataProvider adds any attribute and value to the page element corresponding to the model attribute

For example, there is a class:

Public class User
{
Public string Name {get; set ;}
}

 

On the strong type view page, the input element corresponding to the attribute Name is displayed, and you want to add a title attribute and the corresponding value,

 

□Ideas

→ Custom TooltipAttribute, which can be attached to the Name attribute.
→ Custom DataAnnotationsModelMetadataProvider: place the Tooltip attribute value of TooltipAttribute into ModelMetadata. The value type is the AdditionalValues attribute of the key-value pair.
→ Write an extension method of HtmlHelper <TModel> to obtain the AdditionalValues attribute value of ModelMetadata.

 

Call the custom feature TooltipAttribute to the property.

Using MvcApplication1.Extension;

Namespace MvcApplication1.Models
{
Public class User
{
[Tooltip ("Enter the user name")]
Public string Name {get; set ;}
}
}

 

Custom DataAnnotationsModelMetadataProvider: place the Tooltip attribute value of the custom feature TooltipAttribute into AdditionalValues of ModelMetadata.

 

Extended HtmlHelper <TModel>. First, obtain the ModelMetadata related to the model, from ModelMetadata. in AdditionalValues, the value of Tooltip is typed in the Name attribute of the User. The value is [Tooltip ("enter User Name")] corresponding to the input parameter title = "enter User Name ".

using System.Linq.Expressions;namespace System.Web.Mvc{    public static class TooltipExtension    {        public static MvcHtmlString TooltipFor<TModel, TValue>(this HtmlHelper<TModel> html,            Expression<Func<TModel,TValue>> expression)        {            var modelMetadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);            if (modelMetadata.AdditionalValues.ContainsKey("Tooltip"))            {                return new MvcHtmlString((string)modelMetadata.AdditionalValues["Tooltip"]);            }            return new MvcHtmlString("");        }    }}

 

 

Register the custom DataAnnotationsModelMetadataProvider globally.

Protected void Application_Start ()
{
......

ModelMetadataProviders. Current = new CustomModelMetadataProvider ();
}

 

View:

@ Model MvcApplication1.Models. User
@ Html. TextBoxFor (model => model. Name, new {title = @ Html. TooltipFor (model => model. Name )})

 

References:
Creating your own modelmetadataprovider to handle custom attributes