WinForms: temporarily disable an event handler

Question

How can I disable an event handler temporarily in WinForms?

Answer 1

Probably, the simplest way (which doesn't need unsubscribing or other stuff) is to declare a boolean value and check it at the beginning of the handler:

bool dontRunHandler;

void Handler(object sender, EventArgs e) {
   if (dontRunHandler) return;

   // handler body...
}

Answer 2

I'm doing it in this way, using a control extension.

public static void SetDatasource(
  this ComboBox cb, 
  object dataSource, 
  EventHandler _SelectedIndexChanged_eventHandler = null, 
  EventHandler _SelectedValueChanged_eventHandler = null)
{
//disable events
  if (_SelectedIndexChanged_eventHandler != null) cb.SelectedIndexChanged -= _SelectedIndexChanged_eventHandler;
  if (_SelectedValueChanged_eventHandler != null) cb.SelectedValueChanged -= _SelectedValueChanged_eventHandler;
  if (cb.InvokeRequired)
  {
    cb.BeginInvoke(new _d_SetDatasource_ComboBox(SetDatasource), new object[] { cb, dataSource, _SelectedIndexChanged_eventHandler});
  }
  else
  {
    cb.DataSource = dataSource;
    //events enabled again
    if (_SelectedIndexChanged_eventHandler != null) cb.SelectedIndexChanged += _SelectedIndexChanged_eventHandler;
    if (_SelectedValueChanged_eventHandler != null) cb.SelectedValueChanged += _SelectedValueChanged_eventHandler;
  }
}
private delegate void _d_SetDatasource_ComboBox(ComboBox cb, object dataSource, EventHandler _SelectedIndexChanged_eventHandler = null, EventHandler _SelectedValueChanged_eventHandler = null);

Answer 3

Disable from what perspective? If you want to remove a method that's in your scope from the list of delegates on the handler, you can just do..

object.Event -= new EventHandlerType(your_Method);

This will remove that method from the list of delegates, and you can reattach it later with

object.Event += new EventHandlerType(your_Method);