ASP.Net (3.5) MVC partial class for rule validation - asp.net

Question

I have 2 projects. A data project, which contains my database and my Entity Framework model. I have table called 'User', and then have a generated EF class for user.
I am trying to add a partial class:
using System;
using System.Collections.Generic;
using System.Data.Linq;
using System.Linq;
using System.Text;
namespace Data
{
public partial class user
{
public bool isValid
{
get {
return (GetRuleViolations().Count()==0);
}
}
public IEnumerable<RuleViolation> GetRuleViolations()
{
yield break;
}
partialvoid OnValidate(ChangeAction action)
{
if (isValid)
throw new ApplicationException("Rule violation prevents saving");
}
}
public class RuleViolation
{
public string ErrorMessage { get; private set; }
public string PropertyName { get; private set; }
public RuleViolation (string errorMessage)
{
ErrorMessage = errorMessage;
}
public RuleViolation(string errorMessage, string propertyName)
{
ErrorMessage = errorMessage;
PropertyName = propertyName;
}
}
}
This is following the MVC 1.0 NerdDinner example. However, I am getting a design time error on the OnValidate method:
partial void OnValidate(ChangeAction action)
{
if (isValid)
throw new ApplicationException("Rule violation prevents saving");
}
No definining declaration found for implimenting declaration of partial method 'void OnValidate(ChangeAction action)'
What am I doing wrong?

Answer 1

There should be another file containing the rest of the user class.
In this file you have to declare that there might be a partial method called OnValidate.
public partial class user
{
partial void OnValidate(ChangeAction action);
}
Some detail:
A partial method needs to have a signature specified somewhere. Once the signature has been defined then an optional implementation can be specified. Read http://msdn.microsoft.com/en-us/library/wa80x488.aspx for more information.