How to Register or Unregister Control Event in C# Windows

Here I am explaining Register or Unregister controls event in C# Windows.

Here I am explaining Register or Unregister controls event in C# Windows. Suppose you have a Form in Windows Application. It contain a ComboBox and a label (to show result) like below img.

 

Now In code behind of above form Write below code. . 
 

With the above code, run this application. Now debug the code. you will see that you debugger goes to the combobox_selectindexchanged after the form_load.
 

Bcoz when you write this line "comboBox1.SelectedIndex=0". here you change your combobox index programmatically
 

That's why it call selectindexchange.  To prevent this problem You have to unregistered your control event according to your requirement. Now,

 

On the Form_load you have to unregistered your combobox_selectindexchanged and after the binding of combobox you 

 

have to register your event combobox_selectindexchanged like below img.

 

If there is any suggestion please leave comment.