The ToggleState property is responsible for getting or setting the state of RadToggleButton.

You can handle the ToggleStateChanged event of RadToggleButton to take action when the user toggles the button. The event handler is passed a StateChangedEventArgs parameter that includes a ToggleState member.

Copy[C#] Handling the ToggleStateChanged event

void radToggleButton1_ToggleStateChanged(object sender, StateChangedEventArgs args)
{
    MessageBox.Show(args.ToggleState.ToString());
}

Copy[VB.NET] Handling the ToggleStateChanged event

Private Sub radToggleButton1_ToggleStateChanged(ByVal sender As Object, ByVal args As Telerik.WinControls.UI.StateChangedEventArgs)
    MessageBox.Show(args.ToggleState.ToString())
End Sub

You can also handle the ToggleStateChanging event. This event provides an opportunity to cancel the toggle state change. The StateChangingEventArgs passed as a parameter to the event handler have NewValue and OldValueToggleState members and a Boolean Cancel member. NewValue holds the value of ToggleState that will be applied when the event is completed without being canceled. OldValue holds the value of ToggleState at the time the state change was initiated. Cancel controls which value of ToggleState is applied when the event completes. The default is false. Setting Canceled to true will prevent ToggleStateChanged from firing and will leave the ToggleState value as it was prior to the event.

The example below allows a RadToggleButton to toggle only when a second RadToggleButton is off. If the second button toggle state is On and the NewValue is On, then the toggle is canceled. The ToggleStateChanged event only fires and changes the Text property when ToggleStateChangiing does not cancel.

Copy[C#] Handling the ToggleStateChanging event

private void radToggleButton2_ToggleStateChanging(object sender,
   Telerik.WinControls.UI.StateChangingEventArgs args)
{
    bool attemptingOn = args.NewValue ==
        Telerik.WinControls.Enumerations.ToggleState.On;
    args.Cancel = true;
}

private void radToggleButton2_ToggleStateChanged(object sender,
   Telerik.WinControls.UI.StateChangedEventArgs args)
{
    radToggleButton1.Text = args.ToggleState.ToString();
}

Copy[VB.NET] Handling the ToggleStateChanging event

Private Sub radToggleButton2_ToggleStateChanging(ByVal sender As Object, ByVal args As Telerik.WinControls.UI.StateChangingEventArgs)
    args.Cancel = True
End Sub

Private Sub radToggleButton2_ToggleStateChanged(ByVal sender As Object, ByVal args As Telerik.WinControls.UI.StateChangedEventArgs)
    radToggleButton1.Text = args.ToggleState.ToString()
End Sub