从面板中删除用户控件时捕获事件

Question

I wrote a user control. I have a panel, when I click on the button in user control it is added to the panel. I have created a click event for user control. When clicked, the user control is removed from the panel. I want to ask that to catch the event when the user control is removed, which event should I use and use for panel or user control. For example, I add a label, when adding user control the label will change, and when deleting, the label will also change. Sorry for my bad English.

Answer 1

The event you are most likely to find helpful is the ControlRemoved event of the Control .

This is described in the docs thus:

Occurs when a control is removed from the Control.ControlCollection.

In the case of your example, you would add an event handler for this to the Panel . Assuming your panel is named panel1 (please don't name it that) this would be something like this:

// In initialisation code somewhere
panel1.ControlRemoved += panel1_ControlRemoved;

private void panel1_ControlRemoved(object sender, ControlEventArgs e)
{
    // Do something
    ...
    // Note: removed control is referenced by e.Control
}

This would be raised anytime a control is removed from the Panel .

There's also an accompanying event for when a control is added which is named ControlAdded .