ComboBox.OnDropDown(EventArgs) Method

Definition

Raises the DropDown event.

C#
protected virtual void OnDropDown(EventArgs e);

Parameters

e
EventArgs

An EventArgs that contains the event data.

Remarks

This event is raised each time the drop-down is displayed.

Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.

The OnDropDown method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors

When overriding OnDropDown(EventArgs) in a derived class, be sure to call the base class's OnDropDown(EventArgs) method so that registered delegates receive the event.

Applies to

Product Versions
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
Windows Desktop 3.0, 3.1, 5, 6, 7, 8, 9