When this event occurs, you can check the SelectedIndex property to determine its new value. Alternatively, you can handle the Selected event and use the TabControlEventArgs..::.TabPageIndex property to determine the index of the selected tab page.

For more information about handling events, see Consuming Events.

The following code example demonstrates the use of this member. In the example, an event handler reports on the occurrence of the SelectedIndexChanged 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 type TabControl named TabControl1. Then ensure that the event handler is associated with the SelectedIndexChanged event.

Private Sub TabControl1_SelectedIndexChanged(sender as Object, e as EventArgs) _ 
     Handles TabControl1.SelectedIndexChanged

   MessageBox.Show("You are in the TabControl.SelectedIndexChanged event.")

End Sub

private void TabControl1_SelectedIndexChanged(Object sender, EventArgs e) {

   MessageBox.Show("You are in the TabControl.SelectedIndexChanged event.");

}

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference