protected override void OnValidate()
{
var result = (from person in _dp.GetAll() where person.SSN == _ssn select person).Count <Person>();
if (result != 0)
{
Invalidate("SSN of a new person should be unique! A person with this SSN is already in the database!");
}
}
/// <summary>
/// Invoked by GetAllCommand() if validation and business rules execute successfully
/// </summary>
protected virtual IEnumerable <T> GetAll(ExecutionContext <T> context)
{
return(_dataProxy.GetAll());
}