Specify Double-Click event for a Control in Visual Studio Designer
There is a DefaultEventAttribute that controls can specify. The designer knows to read this attribute and uses it to determine which event to use as the default.
[DefaultEvent("DoubleClick")]
public class MyClass {
public event EventHandler DoubleClick;
}
There is also a DefaultPropertyAttribute which is significantly less useful. It just determines the default property name to select in the property grid when the control is selected in the designer.