private void RestoreWndProc()
{
var currentProc = Win32Native.GetWindowLong(new HandleRef(this, hwnd), Win32Native.WindowLongType.WndProc);
if (currentProc == newWndProcPtr)
{
// Restore back default WndProc only if the previous callback is owned by this message filter hook
Win32Native.SetWindowLong(new HandleRef(this, hwnd), Win32Native.WindowLongType.WndProc, defaultWndProc);
}
}
/// <summary>
/// Initializes a new instance of the <see cref="Win32.MessageFilterHook" /> class.
/// </summary>
/// <param name="hwnd">The HWND.</param>
private MessageFilterHook(IntPtr hwnd)
{
this.currentFilters = new List <IMessageFilter>();
this.hwnd = hwnd;
// Retrieve the previous WndProc associated with this window handle
defaultWndProc = Win32Native.GetWindowLong(new HandleRef(this, hwnd), Win32Native.WindowLongType.WndProc);
// Create a pointer to the new WndProc
newWndProc = WndProc;
newWndProcPtr = Marshal.GetFunctionPointerForDelegate(newWndProc);
// Set our own private wndproc in order to catch NCDestroy message
Win32Native.SetWindowLong(new HandleRef(this, hwnd), Win32Native.WindowLongType.WndProc, newWndProcPtr);
}