public IntPtr PreviewWindowMessage(IntPtr hWindow, int message, IntPtr wParam, IntPtr lParam, ref bool handled)
{
switch (message)
{
case DwmWindowHelper.WmCompositionchanged:
this.NotifyCompositionChanged();
return(IntPtr.Zero);
case DwmWindowHelper.WmNccalcsize:
if (this.DwmIsCompositionEnabled)
{
if (this.nonClientAreaDrawingEnabled &&
wParam != IntPtr.Zero /*TRUE*/)
{
//no nonclient frame
handled = true;
return(IntPtr.Zero);
}
else
{
return(IntPtr.Zero);
}
}
else
{
// Support client drawing only when Dwm is enabled. Otherwise non client drawing is too complicated ;-)
return(IntPtr.Zero);
}
case DwmWindowHelper.WmNchittest:
// Hit test non client area
IntPtr Result = IntPtr.Zero;
if (this.DwmIsCompositionEnabled)
{
// if Dwm is enabled,first let DWM hit test for window buttons
handled = DwmApi.DwmDefWindowProc(hWindow, message, wParam, lParam, out Result);
}
if (handled == false)
{
// hit test for non client areas in the window layout
uint Coordinates;
checked
{
Coordinates = (uint)lParam.ToInt32();
}
NonClientArea NonClientArea = this.nonClientHitTest(Coordinates.GetLoUShort(), Coordinates.GetHiUShort());
if (NonClientArea != NonClientArea.HTNOWHERE)
{
Result = new IntPtr((int)NonClientArea);
handled = true;
}
}
return(Result);
default:
return(IntPtr.Zero);
}
}
public IntPtr PreviewWindowMessage(IntPtr hWindow, int message, IntPtr wParam, IntPtr lParam, ref bool handled)
{
switch (message)
{
case WM_COMPOSITIONCHANGED:
this.NotifyCompositionChanged();
return(IntPtr.Zero);
case WM_NCCALCSIZE:
if (this.firstTimeNonClientCalc)
{
// Suppress first time, otherwise glass effect will be messed up..
this.firstTimeNonClientCalc = false;
return(IntPtr.Zero);
}
else
{
if (this.nonClientAreaDrawingEnabled && wParam != IntPtr.Zero) //TRUE
{
//no nonclient frame
handled = true;
return(IntPtr.Zero);
}
else
{
return(IntPtr.Zero);
}
}
case WM_NCHITTEST:
IntPtr Result = IntPtr.Zero;
if (this.dwmIsCompositionEnabled)
{
handled = DwmAPI.DwmDefWindowProc(hWindow, message, wParam, lParam, out Result);
}
if (handled == false)
{
uint Coordinates;
checked
{
Coordinates = (uint)lParam.ToInt32();
}
NonClientArea NonClientArea = this.nonClientHitTest(Coordinates.GetLoUShort(), Coordinates.GetHiUShort());
if (NonClientArea != NonClientArea.HTNOWHERE)
{
Result = new IntPtr((int)NonClientArea);
handled = true;
}
}
return(Result);
default:
return(IntPtr.Zero);
}
}
private NonClientArea NonClientHitTest(ushort x, ushort y)
{
Point Coordinate = this.PointFromScreen(new Point(x, y));
HitTestResult HitTest = VisualTreeHelper.HitTest(this, Coordinate);
if (HitTest?.VisualHit != null)
{
NonClientArea Area = NonClientAreaRegion.GetNonClientAreaType(HitTest.VisualHit);
return(Area);
}
else
{
return(NonClientArea.HTNOWHERE);
}
}
/// <summary>
/// sets the nonclient area type that controls how the window manager reacts on user interaction with the NC area
/// </summary>
public static void SetNonClientAreaType(DependencyObject d, NonClientArea value)
{
d.SetValue(NonClientAreaRegion.NonClientAreaTypeProperty, value);
}