public override void Assign(RepositoryItem item)
 {
     BeginUpdate();
     try
     {
         base.Assign(item);
         MyRepositoryItemGridLookUpEdit source = item as MyRepositoryItemGridLookUpEdit;
         if (source == null)
         {
             return;
         }
         GridSelection = source.GridSelection;
     }
     finally
     {
         EndUpdate();
     }
 }
 //The static constructor which calls the registration method
 static MyGridLookUpEdit()
 {
     MyRepositoryItemGridLookUpEdit.RegisterMyRepositoryItemGridLookUpEdit();
 }