asp.net mvc自定义MetadataProvider

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace ValidationSample
{
public class ConventionMetadataProvider : AssociatedMetadataProvider
{
public ConventionMetadataProvider() : base()
{
}

protected override ModelMetadata CreateMetadata(IEnumerable<Attribute> attributes, Type containerType, Func<object> modelAccessor, Type modelType, string propertyName)
{
var metadata = new ModelMetadata(this, containerType, modelAccessor, modelType, propertyName);

if (propertyName == null)
return metadata;

if (propertyName.EndsWith("Id"))
{
metadata.TemplateHint = "HiddenInput";
metadata.HideSurroundingChrome = true;
}

if (propertyName.EndsWith("X"))
{
metadata.IsRequired = true;
}

metadata.DisplayName = propertyName.TrimEnd('X').Wordify();

return metadata;
}
}

public static class Extensions
{
public static string Wordify(this string str)
{
string newString = "";
foreach(char c in str) {
newString += char.IsUpper(c) ? " " + c : c.ToString();
}

return newString;
}
}

}

using System;
using System.Collections.Generic;
using System.Web.Mvc;

namespace ValidationSample
{
public class ConventionValidatorProvider : AssociatedValidatorProvider
{
protected override IEnumerable<ModelValidator> GetValidators(ModelMetadata metadata, ControllerContext context,
IEnumerable<Attribute> attributes)
{
if (metadata.IsRequired)
{
yield return new MyRequiredValidator(metadata, context);
}
}

#region Nested type: MyRequiredValidator

public class MyRequiredValidator : ModelValidator
{
internal MyRequiredValidator(ModelMetadata metadata, ControllerContext context)
: base(metadata, context)
{
}

public override IEnumerable<ModelValidationResult> Validate(object container)
{
var result = new List<ModelValidationResult>();
if (Metadata.Model == null)
result.Add(new ModelValidationResult
{
MemberName = Metadata.PropertyName,
Message = string.Format("{0} is required", Metadata.DisplayName)
});

return result;
}

public override IEnumerable<ModelClientValidationRule> GetClientValidationRules()
{
yield return new ModelClientValidationRequiredRule("This field is required");
}
}

#endregion
}
}

protected void Application_Start()
{
ModelMetadataProviders.Current = new ConventionMetadataProvider();
ModelValidatorProviders.Current = new ConventionValidatorProvider();

RegisterRoutes(RouteTable.Routes);
}