Invalidated Event

Control.Invalidated Event


Occurs when a control's display requires redrawing.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public event InvalidateEventHandler Invalidated

For more information about handling events, see Handling and Raising Events.

The following code example demonstrates the use of this member. In the example, an event handler reports on the occurrence of the Invalidated event. This report helps you to learn when the event occurs and can assist you in debugging. To report on multiple events or on events that occur frequently, consider replacing MessageBox.Show with Console.WriteLine or appending the message to a multiline TextBox.

To run the example code, paste it into a project that contains an instance of a type that inherits from Control, such as a Button or ComboBox. Then name the instance Control1 and ensure that the event handler is associated with the Invalidated event.

private void Control1_Invalidated(Object sender, InvalidateEventArgs e) {

System.Text.StringBuilder messageBoxCS = new System.Text.StringBuilder();
messageBoxCS.AppendFormat("{0} = {1}", "InvalidRect", e.InvalidRect );
MessageBox.Show(messageBoxCS.ToString(), "Invalidated Event" );

.NET Framework
Available since 1.1
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