private IntPtr WindowProcedure(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam)
{
switch (msg)
{
case WindowMessage.EraseBackground:
User32.SendMessage(hwnd, WindowMessage.Paint, (IntPtr)0, (IntPtr)0);
break;
case WindowMessage.Keyup:
case WindowMessage.Keydown:
case WindowMessage.Syscommand:
case WindowMessage.Syskeydown:
case WindowMessage.Syskeyup:
return((IntPtr)0);
case WindowMessage.NcPaint:
case WindowMessage.Paint:
return((IntPtr)0);
case WindowMessage.DwmCompositionChanged:
WindowHelper.ExtendFrameIntoClientArea(hwnd);
return((IntPtr)0);
case WindowMessage.DpiChanged:
return((IntPtr)0); // block DPI changed message
default: break;
}
return(User32.DefWindowProc(hwnd, msg, wParam, lParam));
}
/// <summary>
/// Makes the window visible.
/// </summary>
public void Show()
{
if (!_isInitialized)
{
throw new InvalidOperationException("OverlayWindow not initialized");
}
User32.ShowWindow(_handle, ShowWindowCommand.Show);
_isVisible = true;
WindowHelper.ExtendFrameIntoClientArea(_handle);
OnVisibilityChanged(true);
}
private void RemoveTopmost()
{
if (!_isTopmost)
{
return;
}
WindowHelper.RemoveTopmost(_handle);
_isTopmost = false;
if (_isVisible)
{
WindowHelper.ExtendFrameIntoClientArea(_handle);
}
}
/// <summary>
/// Changes the size of the window using the given width and height.
/// </summary>
/// <param name="width">The new width of the window.</param>
/// <param name="height">The new height of the window.</param>
public void Resize(int width, int height)
{
if (!_isInitialized)
{
throw new InvalidOperationException("OverlayWindow not initialized");
}
User32.MoveWindow(_handle, _x, _y, width, height, true);
_width = width;
_height = height;
WindowHelper.ExtendFrameIntoClientArea(_handle);
OnSizeChanged(width, height);
}
/// <summary>
/// Changes the position of the window using the given coordinates.
/// </summary>
/// <param name="x">The new x-coordinate of the window.</param>
/// <param name="y">The new y-coordinate of the window.</param>
public void Move(int x, int y)
{
if (!_isInitialized)
{
throw new InvalidOperationException("OverlayWindow not initialized");
}
User32.MoveWindow(_handle, x, y, _width, _height, true);
_x = x;
_y = y;
WindowHelper.ExtendFrameIntoClientArea(_handle);
OnPositionChanged(x, y);
}
private void MakeTopmost()
{
if (_isTopmost)
{
return;
}
WindowHelper.MakeTopmost(_handle);
_isTopmost = true;
if (!_isVisible)
{
WindowHelper.ExtendFrameIntoClientArea(_handle);
_isVisible = true;
OnVisibilityChanged(true);
}
}
private void SetupWindow()
{
// generate a random title if it's null (invalid)
if (_title == null)
{
_title = WindowHelper.GenerateRandomTitle();
}
if (string.IsNullOrEmpty(MenuName))
{
MenuName = WindowHelper.GenerateRandomTitle();
}
// if no class name is given then generate a "unique" one
if (string.IsNullOrEmpty(_className))
{
_className = WindowHelper.GenerateRandomClass();
}
// prepare window procedure
_windowProc = WindowProcedure;
_windowProcAddress = Marshal.GetFunctionPointerForDelegate(_windowProc);
// try to register our class
while (true)
{
var wndClassEx = new WindowClassEx
{
Size = WindowClassEx.NativeSize(),
Style = 0,
WindowProc = _windowProcAddress,
ClsExtra = 0,
WindowExtra = 0,
Instance = IntPtr.Zero,
Icon = IntPtr.Zero,
Curser = IntPtr.Zero,
Background = IntPtr.Zero,
MenuName = MenuName,
ClassName = _className,
IconSm = IntPtr.Zero
};
if (User32.RegisterClassEx(ref wndClassEx) != 0)
{
break;
}
else
{
// already taken name?
_className = WindowHelper.GenerateRandomClass();
}
}
var extendedWindowStyle = ExtendedWindowStyle.Transparent | ExtendedWindowStyle.Layered | ExtendedWindowStyle.NoActivate;
if (_isTopmost)
{
extendedWindowStyle |= ExtendedWindowStyle.Topmost;
}
var windowStyle = WindowStyle.Popup;
if (_isVisible)
{
windowStyle |= WindowStyle.Visible;
}
_handle = User32.CreateWindowEx(
extendedWindowStyle,
_className,
_title,
windowStyle,
_x, _y,
_width, _height,
IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero);
User32.SetLayeredWindowAttributes(_handle, 0, 255, LayeredWindowAttributes.Alpha);
User32.UpdateWindow(_handle);
// if the window is incompatible on some platforms then use
// SetWindowLong and UpdateWindow to set the style again and
// call SetWindowPos with SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED
if (_isVisible)
{
WindowHelper.ExtendFrameIntoClientArea(_handle);
}
}