private void Move_Column_Left_Click(object sender, RoutedEventArgs e)
 {
     if (this.selectedData != null)
     {
         InfoObject info = SystemInterface.moveColumnBack(userName, (int)this.selectedData.Tag);
         if (info.getIsSucceeded())
         {
             this.selectedData = null;
             this.show(SystemInterface.getBoard(userName));
         }
         else
         {
             MessageBox.Show(info.getMessage());
         }
     }
     else
     {
         MessageBox.Show("Please select column");
     }
 }