public class LightSwitch : Control
{
    // Not a complete Silverlight custom control but enough 
    // to demonstrate providing accessibility support via 
    // AutomationPeer and UI Automation
 
    private bool _stateOn;
    public LightSwitch(){}

    public bool State
    {
        get
        {
            return this._stateOn;
        }

        set
        {
            changeState(value);
        }
    }

    protected override void       OnMouseLeftButtonDown(MouseButtonEventArgs e)
    {
        e.Handled = true;
        base.OnMouseLeftButtonDown(e);
        this.Toggle();
    }

    public void Toggle()
    {
        changeState(!this._stateOn);
    }

    protected override AutomationPeer OnCreateAutomationPeer()
    {
        return new LightSwitchAutomationPeer(this);
    }

    public void changeState(bool newState)
    {
        
        // notify accessibility that the state changed
        LightSwitchAutomationPeer ap =       FrameworkElementAutomationPeer.FromElement(this) as         LightSwitchAutomationPeer;

        if (ap != null)
        {
            ap.RaiseStateChangedEvent(this._stateOn, newState);
        }

        // flip light switch state
        this._stateOn = !this._stateOn;

        // update visuals
        this.updateVisuals(this._stateOn);
    }
}