How to add validation to my POCO(template) classes

Question

So I used this tutorial to generate my poco classes which I am to use throughout my aplication.. the problem is that Im not supposed to modify the generated cs files cause they get autoregenerated... How do I add attributes like [Required] and stuff like that?? please help

Answer 1

You can't add it directly (unless you modify T4 template to create them for you) but you can try to use trick introduced in ASP.NET dynamic data. All POCO classes are defined as partial. So lets define your partial part:

using System.ComponentModel.DataAnnotations;

[MetadataType(typeof(MyClassMetadata))]
public partial class MyClass
{
  private class MyClassMetadata
  {
     [Required]
     public object Id;

     [Required]
     [StringLength(100)]
     public object Name;
  }
}

Metadata class is special type to hold only metadata - it is never used. Name of fields must be same as corresponding fields in real class (field types doesn't matter so you can use object).

Anyway in ASP.NET MVC you should use specialized View model for each view and pass data you need so the validation attributes will be placed in view model class.