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 static bool IsCompositionEnabled()
{
try
{
return(DwmApi.DwmIsCompositionEnabled());
}
catch (DllNotFoundException)
{
return(false);
}
}
internal DwmWindowHelper(IntPtr windowHandle, DwmApi.Margins margins, bool blurClientArea, bool nonClientAreaDrawingEnabled, Action notifyDwmCompositionChanged, Func <ushort, ushort, NonClientArea> nonClientHitTest)
{
this.WindowHandle = windowHandle;
this.DwmIsCompositionEnabled = DwmApi.IsCompositionEnabled();
this.margins = margins;
this.blurClientArea = blurClientArea;
this.notifyDwmCompositionChanged = notifyDwmCompositionChanged;
this.UpdateGlassEffect();
this.UpdateNonClientArea();
this.nonClientAreaDrawingEnabled = nonClientAreaDrawingEnabled;
this.nonClientHitTest = nonClientHitTest;
this.UpdateNonClientArea();
}
public static void EnableBlurBehindWindow(IntPtr windowHandle, bool enable)
{
try
{
if (DwmApi.DwmIsCompositionEnabled())
{
BlurBehindInformation BlurBehindInformation = new BlurBehindInformation(enable, IntPtr.Zero);
DwmApi.DwmEnableBlurBehindWindow(windowHandle, ref BlurBehindInformation);
return;
}
else
{
//Glass effect is not enabled -> do nothing
return;
}
}
catch (DllNotFoundException)
{
return;
}
}
internal static void EnableGlassEffect(IntPtr windowHandle, Margins margins)
{
try
{
if (DwmApi.DwmIsCompositionEnabled())
{
IntPtr Handle = windowHandle;
DwmApi.DwmExtendFrameIntoClientArea(Handle, ref margins);
return;
}
else
{
//Glass effect is not enabled -> do nothing
return;
}
}
catch (DllNotFoundException)
{
return;
}
}
protected void NotifyCompositionChanged()
{
this.DwmIsCompositionEnabled = DwmApi.IsCompositionEnabled();
this.UpdateGlassEffect();
this.notifyDwmCompositionChanged();
}
private void UpdateGlassEffect()
{
DwmApi.EnableGlassEffect(this.WindowHandle, this.margins);
DwmApi.EnableBlurBehindWindow(this.WindowHandle, this.blurClientArea);
}
private void UpdateNonClientArea()
{
DwmApi.SetWindowPos(this.WindowHandle, IntPtr.Zero, 0, 0, 0, 0, 0x27 /*SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED*/);
}
