private void OnPreviewMouseWheel(IInputElement originalSource, MouseWheelInputEventArgs ie)
{
// Update wheel motion info
var info = ie.Wheel.PreTransmit(ie.Timestamp, ie.Delta);
// 1. Tunneling event
// Clients and behaviors use this tunneling event to update the wheel transfer
// case by dynamically creating / retrieving motion shafts.
ie.RoutedEvent = PreviewMouseWheelInputEvent;
originalSource.RaiseEvent(ie);
// In cooperation with clients and behaviors, if inputEventArgs.Handled is set to true,
// the controller lets the underlying mouse wheel tunneling event continue its route.
if (ie.Handled)
{
return;
}
// Fill motion reservoir
ie.Wheel.Transmit(info, ie.Delta, null);
// 2. Bubbling event
// Clients consume the motion here
ie.RoutedEvent = MouseWheelInputEvent;
originalSource.RaiseEvent(ie);
// 3. Remaining motion is processed here
ie.EndCommand();
}
private void OnPreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
var originalSource = this.GetOriginalSource(e);
var ie = new MouseWheelInputEventArgs(this, e.MouseDevice.GetWheel(), e.Timestamp, e.Delta, Orientation.Vertical);
this.OnPreviewMouseWheel(originalSource, ie);
e.Handled = true;
}
private void OnPreviewInput(object sender, MouseWheelInputEventArgs e)
{
Debug.Assert(sender == this.Element);
var client = this._clients.FirstOrDefault(c => c.IsActive(e));
if (client != null)
{
client.OnPreviewInput(sender, e);
}
}
private void OnInput(object sender, MouseWheelInputEventArgs e)
{
Debug.Assert(sender == this.Element);
e.Controller = this;
var client = this._clients.FirstOrDefault(c => c.IsActive(e));
if (client != null)
{
this._exitElement = client.ExitElement;
client.OnInput(sender, e);
}
}
protected bool TransferMotion(MouseWheelInputEventArgs e)
{
var shaft = this.GetMotionShaft(e.Wheel);
if (shaft.Transfer(this.MotionInput, e))
{
return(true); // client can still move - stop event propagation
}
if (this.NestedMotionEnabled)
{
return(false); // let the mouse wheel event propagate up the visual tree
}
// empty the shaft transfer staging area and stop event propagation
return(shaft.Transfer(NativeMotionTarget.Terminal, e));
}
private IntPtr MouseHorizontalWheelHook(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
switch (msg)
{
case WM_MOUSEHWHEEL:
{
var timestamp = Environment.TickCount;
var originalSource = Mouse.DirectlyOver;
var delta = wParam.ToInt32() >> 16;
var ie = new MouseWheelInputEventArgs(this, MouseWheel.Current, timestamp, -delta, Orientation.Horizontal);
this.OnPreviewMouseWheel(originalSource, ie);
break;
}
}
return(IntPtr.Zero);
}
public virtual void OnInput(object sender, MouseWheelInputEventArgs e)
{
e.Handled = this.TransferMotion(e);
}
public virtual void OnPreviewInput(object sender, MouseWheelInputEventArgs e)
{
e.Handled = this.GetMotionShaft(e.Wheel) == null;
}
protected bool TransferMotionNative(MouseWheelInputEventArgs e)
{
return(this.GetMotionShaft(e.Wheel).Transfer(this, e));
}
public override bool IsActive(MouseWheelInputEventArgs e)
{
return(e.Orientation == Orientation.Vertical && base.IsActive(e));
}