Re: using a modeless WinForms "application" from MFC

From:
"Sheng Jiang[MVP]" <sheng_jiang@hotmail.com.discuss>
Newsgroups:
microsoft.public.dotnet.framework.interop,microsoft.public.dotnet.framework.windowsforms,microsoft.public.vc.mfc
Date:
Wed, 15 Aug 2007 12:36:16 -0500
Message-ID:
<Ob3VKL23HHA.4436@TK2MSFTNGP03.phx.gbl>
code

// CMFCWinFormHybridApp initialization
#pragma managed
extern void ManagedInit();
#pragma unmanaged
BOOL CMFCWinFormHybridApp::InitInstance()
{
 ManagedInit();
....

#pragma managed
bool MFCMessageFilter(HWND hwnd,UINT message,LONG x,LONG y,DWORD time,
WPARAM wparam, LPARAM lparam)
{
 _AFX_THREAD_STATE *pState = AfxGetThreadState();

 pState->m_msgCur.hwnd=hwnd;
 pState->m_msgCur.message=message;
 pState->m_msgCur.pt.x=x;
 pState->m_msgCur.pt.y=y;
 pState->m_msgCur.time=time;
 pState->m_msgCur.wParam=wparam;
 pState->m_msgCur.lParam=lparam;
 if(message==WM_KICKIDLE)
  return true;
 bool mfcPretranslate=(bool)AfxPreTranslateMessage(&(pState->m_msgCur));
 return mfcPretranslate;
}
ref class CMFCMessageFilter:public System::Windows::Forms::IMessageFilter
{
public:

[System::Security::Permissions::SecurityPermission(System::Security::Permiss
ions::SecurityAction::LinkDemand,
Flags=System::Security::Permissions::SecurityPermissionFlag::UnmanagedCode)]
 virtual bool PreFilterMessage(System::Windows::Forms::Message % m)
 {
  return
MFCMessageFilter((HWND)m.HWnd.ToPointer(),m.Msg,0,0,0,(WPARAM)m.WParam.ToPoi
nter(),(LPARAM)m.LParam.ToPointer());
 }
};
void ManagedInit()
{
 System::Windows::Forms::Application::AddMessageFilter(gcnew
CMFCMessageFilter());
}
void ManagedRun()
{
 System::Windows::Forms::Application::Run();
}

#pragma unmanaged

int CMFCWinFormHybridApp::Run()
{
 if (m_pMainWnd == NULL && AfxOleGetUserCtrl())
 {
  // Not launched /Embedding or /Automation, but has no main window!
  TRACE(traceAppMsg, 0, "Warning: m_pMainWnd is NULL in CWinApp::Run -
quitting application.\n");
  AfxPostQuitMessage(0);
 }
 ManagedRun();
 return ExitInstance();
 //return CWinApp::Run();
}
--
Sheng Jiang
Microsoft MVP in VC++
"Sheng Jiang[MVP]" <sheng_jiang@hotmail.com.discuss> wrote in message
news:eJzgI6s3HHA.5980@TK2MSFTNGP04.phx.gbl...

I remember a while ago I have a demo app in which I have my CHTMLView

based

app work on a windows form message pump... basically override CWinApp::Run
and call Application::Start instead of calling CWinThread::Run . To make
PretranslateMessage work I added my own IMessageFilter implementation to

the

application and call MFC's CWinApp::PreTranslateMessage in it. Haven't
tested it extensively, though.

--
Sheng Jiang
Microsoft MVP in VC++
"Dan Smith" <Dan Smith@nospam.nospam> wrote in message
news:DFF43913-3DD5-4F32-AB53-9BDA2F5B04B5@microsoft.com...

I'm in the process of adding a bunch of new .NET functionality to a

(poorly

behaved) legacy MFC application. One of the things I'm adding is a

"source

code editor" (ala VBA): the window should minimize/restore separately

from

the main application, have its own menu/toolbar, etc.

The first approach was straight-forward enough: create the "application"

as

a Form and use it as a modeless dialog. However, things didn't work

right

with menu keyboard accelerators and the like (Ctrl-C, Alt-X, F1),

apparently

a result of the main MFC application grabbing them.

So, the approach that I've been using for the past several weeks is to
create my own Application in a separate thread. See


http://discuss.develop.com/archives/wa.exe?A2=ind0401a&L=dotnet-winforms&T=0&F=&S=&P=3005

 and

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=193220&SiteID=1.

This has been working reasonably well, also having to Invoke() back to

the

main thread at times is a pain.

However, I'm now seeing some crashes with very strange call stacks such

as:

    System.OutOfMemoryException: Out of memory.
       at System.Drawing.Graphics.FromHdcInternal(IntPtr hdc)
       at System.Windows.Forms.PaintEventArgs.get_Graphics()
       at System.Windows.Forms.Control.PaintException(PaintEventArgs e)
       at

System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs

e, Int16 layer, Boolean disposeEventArgs)
       at System.Windows.Forms.Control.WmEraseBkgnd(Message& m)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       at System.Windows.Forms.ContainerControl.WndProc(Message& m)
       at System.Windows.Forms.UserControl.WndProc(Message& m)
       at
System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at

System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message&

m)
       at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32

msg,

IntPtr wparam, IntPtr lparam)
this seems to occur when the user tries to move my "application" window
immediately after I've Invoke()d to the main thread. Also, I'd like a
little bit better window management integration with the legacy MFC
application; for example, I don't want one of its modal (error) dialogs

to

get hidden behind this editor application window.

With that extensive background; the most recent thing I've tried is to

use

this top-level Form from MFC via the CWinFormsDialog<> class. After

setting

TopLevel=false on my Form, the form is displayed--although the results

are

quirky as I see two sets of non-client area items (close, minimize,
maximize, etc.). But the bigger problem is that I can't get the

keyboard

accelerators working. I've overridden PreTranslateMessage() and tried
calling Control.PreProcessMessage() (and the like), but it doesn't seem

to

work.

At this point, I'm trying to figure out where to go next: sticking with

a

separate .NET Application in it's own thread is fine, but I've got no

idea

what could be causing the crash above. And even then, there are still
glitches with getting windows "owned" correctly (and the legacy MFC
application has it's own ideas too).

Switching to MFC for at least some of the "application" shell (although

as

absolutely little as possible in MFC!) might help, but not if I can't

get

the keyboard accelerators. Is what I'm trying to do in MFC possible?
supported? If not, what are the alternatives? My .NET UI has docking
windows and MDI; I *really* don't want to have to do all that "shell" in
MFC--even if the content are WinForms controls.

Thanks for any tips/advice/pointers/etc.

   Dan

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