// This is the initializer WindowProc for the class. It is only called until the NCCREATE message
// is arrived, at which point the WindowInstanceInitializerProc is called, which again is only
// executed once. It performs nifty trick to replace the WindowProc of the instance, by chaining
// WndProc and swapping out base classes to be able to do it without any extra overhead of the
// traditional Win32 WndProc methods.
private unsafe IntPtr ClassInitializerProc(IntPtr hwnd, uint msg, IntPtr wParam, IntPtr lParam)
{
try
{
Debug.WriteLine("[ClassInitializerProc]: " + hwnd);
WindowProc winInstanceInitializerProc = null;
if (msg == (int)WM.NCCREATE)
{
var wParamForNcCreate = Marshal.GetFunctionPointerForDelegate(this.m_windowProc);
var createStruct = *(CreateStruct *)lParam.ToPointer();
var instancePtr = createStruct.CreateParams;
if (instancePtr != IntPtr.Zero)
{
var winInstance = (WindowCore)GCHandle.FromIntPtr(instancePtr).Target;
if (winInstance != null)
{
winInstanceInitializerProc = winInstance.WindowInstanceInitializerProc;
wParam = wParamForNcCreate;
}
}
}
return(winInstanceInitializerProc?.Invoke(hwnd, msg, wParam, lParam) ??
this.m_windowProc(hwnd, msg, wParam, lParam));
}
catch (Exception ex)
{
if (!WindowCore.HandleException(ex, null))
{
throw;
}
return(IntPtr.Zero);
}
}
public static bool HandleException(Exception ex, WindowCore window)
{
var windowException = new WindowException(ex, window);
window?.Exception?.Invoke(windowException);
if (!windowException.IsHandled)
{
UnhandledException?.Invoke(windowException);
}
return(windowException.IsHandled);
}
public int Run(WindowCore mainWindow = null)
{
Action destroyHandler = () => { MessageHelpers.PostQuitMessage(); };
if (mainWindow != null)
{
mainWindow.Destroyed += destroyHandler;
}
var res = this.RunCore();
// Technically, this can be avoided by setting the handler to auto disconnect.
// However, this helps keep the mainWindow alive, and use this instead of
// GC.KeepAlive pattern.
if (mainWindow != null)
{
mainWindow.Destroyed -= destroyHandler;
}
return(res);
}
public WindowException(Exception ex, WindowCore window, string message) : base(message, ex)
{
this.Window = window;
this.IsHandled = false;
}
public WindowException(Exception ex, WindowCore window) : this(ex, window, null)
{
}