This approach for exchanging data between managed and unmanaged parts of the project uses PInvoke in .NET to access native APIs in dynamic link libraries (DLLs). Additionally, we will explain a method for placing an MFC control into a WinForm project. The procedure is simple:

1. Place the control onto an MFC dialog.

2. Prepare a regular DLL with the dialog and call it as a modeless dialog, adding the following code into the DLL (MFC part of the project):

   extern "C" __declspec(dllexport) int CallDlg( HWND hWndParent ) { AFX_MANAGE_STATE(AfxGetStaticModuleState()); pDlg = new CMyDialog ( CWnd::FromHandle( hWndParent ) ); pDlg->Create(IDD_DIALOG); return 0; } int CMyDlgApp::ExitInstance() { delete pDlg; return CWinApp::ExitInstance(); }

3. Choose the CHILD style in the dialog properties.

4. Pass the WinForm handle into the dialog's constructor.

5. Add an attribute and a function declaration in the C# program:

   [DllImport("MyDlg.dll")] public static extern int CallDlg( int hWnd );

   The following code is used to call a modeless MFC dialog from the C# program:

   private void Form1_Activated(object sender, System.EventArgs e) { if (bFirst == true) { CallDlg(this.Handle.ToInt32()); bFirst = false; } }

6. Override the appropriate handlers to adjust reactions to mouse and keyboard messages.

The procedure described in this section is a common method for placing an MFC-based control onto a WinForm, calling it as a modeless dialog. The following examples apply this procedure to dialog applications that wrap both the Objective Views and the Objective Grid components.