private void dgMain_PreviewKeyUp(object sender, KeyEventArgs e)
 {
     if (e.Key == Key.Enter)
     {
         if (_viewModel.AllowNew)
         {
             _viewModel.NewSecurityGroupCommand("");
             //set the first visible column to allow for edit w/o requireing a click to select it...
             dgMain.CurrentCell = new DataGridCellInfo(
                 dgMain.Items[dgMain.Items.Count - 1], dgMain.Columns[0]);
             dgMain.BeginEdit();
         }
         else
         {
             MessageBox.Show("New SecurityGroup Is Not Enabled...", "Error", MessageBoxButton.OK, MessageBoxImage.Error);
         }
     }
 }