How to “Unset” Event

Question

If I have a combobox click event set in the designer.cs page and then at some point during the running of the program, based on some condition, I no longer want the combobox Click event to be set, how do I "unset" it? I've tried comboboxname.Click += null and I've tried setting it to another dummy function that does nothing...neither works.

Answer 1

Assuming your handler is assigned like this:

this.comboBox1_Click += new System.EventHandler(this.comboBox1_Click);

disable it like this:

this.comboBox1.Click -= new System.EventHandler(this.comboBox1_Click);

Answer 2

The reason you cannot use

comboboxname.Click = null

or

comboboxname.Click += null

is that the event Click actually contains a list of event handlers. There may be multiple subscribers to your event and to undo subscribing to an event you have to remove only your own event handler. As it has been pointed out here you use the -= operator to do that.

Answer 3

Use the -= operator.

this.MyEvent -= MyEventHandler;

Your question indicates you don't have a good understanding of events in c# - I suggest looking deeper into it.

Answer 4

Set:

comboBox.Click += EventHandler;

Unset:

comboBox.Click -= EventHandler;

Answer 5

 //to subscribe
 comboboxname.Click += ComboboxClickHandler; 

 //to conditionally unsubscribe
 if( unsubscribeCondition)
 {
   comboboxname.Click -= ComboboxClickHandler;
 }