http://www.cnblogs.com/artech/archive/2012/04/10/how-mvc-works.html
http://www.cnblogs.com/artech/archive/2012/06/07/data-annotations-model-validation-02.html
ModelValidator继承层次结构
System.Object
System.Web.Mvc.ModelValidator
System.Web.Mvc.DataAnnotationsModelValidator
System.Web.Mvc.DataAnnotationsModelValidator<TAttribute>
System.Web.Mvc.MaxLengthAttributeAdapter
System.Web.Mvc.MinLengthAttributeAdapter
System.Web.Mvc.RangeAttributeAdapter
System.Web.Mvc.RegularExpressionAttributeAdapter
System.Web.Mvc.RequiredAttributeAdapter
System.Web.Mvc.StringLengthAttributeAdapter
System.Web.Mvc.ModelValidator
System.Web.Mvc.DataAnnotationsModelValidator
System.Web.Mvc.DataAnnotationsModelValidator<TAttribute>
System.Web.Mvc.MaxLengthAttributeAdapter
System.Web.Mvc.MinLengthAttributeAdapter
System.Web.Mvc.RangeAttributeAdapter
System.Web.Mvc.RegularExpressionAttributeAdapter
System.Web.Mvc.RequiredAttributeAdapter
System.Web.Mvc.StringLengthAttributeAdapter