/// <summary>
/// A Window procedure - handles window messages for a window.
/// Pass this method to HwndSource.AddHook().
/// </summary>
/// <param name="hwnd">The window handle.</param>
/// <param name="msg">The message.</param>
/// <param name="wParam">Message data.</param>
/// <param name="lParam">Message data.</param>
/// <param name="handled">Set to true if the message has been handled</param>
/// <returns>The message result.</returns>
public IntPtr WindowProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
switch ((WindowsApi.WindowMessages)msg)
{
case WindowsApi.WindowMessages.WM_CLIPBOARDUPDATE:
// The clipboard has been updated.
this.gotClipboard.Set();
handled = true;
break;
default:
if (msg == this.shellMessage)
{
// A window has been activated.
if (wParam.ToInt32() == WindowsApi.HSHELL_WINDOWACTIVATED ||
wParam.ToInt32() == WindowsApi.HSHELL_RUDEAPPACTIVATED)
{
// The activated window is passed via lParam, but this wasn't accurate
// for Modern UI apps.
IntPtr window = WindowsApi.GetForegroundWindow();
if (this.activeWindow != window)
{
this.activeWindow = window;
// Ignore the application's window
WindowsApi.GetWindowThreadProcessId(window, out uint pid);
if (pid != this.processId && pid != 0)
{
this.lastWindow = window;
}
this.activeWindowChanged.Set();
}
}
}
break;
}
return(IntPtr.Zero);
}
/// <summary>
/// Activates a window, does not return until it is activated.
/// </summary>
/// <param name="hwnd">The handle of the window to activate.</param>
private void ActivateWindow(IntPtr hwnd)
{
if (hwnd != IntPtr.Zero)
{
// Activate the window, if it's not already.
IntPtr active = WindowsApi.GetForegroundWindow();
if (active != hwnd)
{
// Wait for it to be activated. For unknown reasons, activating the window the first time causes
// no window to be activated. The second attempt works.
const int timeout = 2000;
int start = Environment.TickCount;
int timespent = 0;
do
{
WindowsApi.SetForegroundWindow(hwnd);
this.activeWindowChanged.Reset();
this.activeWindowChanged.WaitOne(timeout - timespent);
timespent = Environment.TickCount - start;
} while (this.activeWindow != hwnd && timespent <= timeout);
}
}
}
