Creating a template for dialog wrapper

[Nobody/Anonymous]

Hi,

the last days I tried to do a simple dialog wrapper class (inspired by some tutorials/articles) an as I am a newbie to this, I am happy that I got it work!
(at least I got no more system errors!)

Now I wanted to make this a template for new DEV-C++ projects.

First:
Can anyone check if this code is not too dangerous?

Second:
How can I make it a DEV-C++ template.

Thank you
Tom

PS:
Here is the source

===============

WinMain.cpp

// Include the stuff you need

include "CBaseDlg.h"

// Windows main function
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)

{
// First instance of the base dialog class
CBaseDlg MainDlg;

// Run the main dialog
return MainDlg.RunDlg(MainDlg.CreateDlg(IDD_DLG));
}

==================================================================================================

CBaseDlg.h

ifndef BASE_DLG_H

define BASE_DLG_H

define STRICT // For strict type checking

include <windows.h> // Include windows stuff

include "Resource.h"

// Declaration of base dialog window class
class CBaseDlg
{
public:

CBaseDlg();             // Constructor
virtual ~CBaseDlg();    // Destructor

// Declare static dialog box procedure, it's a windows callback function and has to be static
// This procedure will call the dialog objects member function
static BOOL CALLBACK DlgProcStatic(HWND m_hWnd, unsigned int uiMessage, WPARAM wParam, LPARAM lParam);

//  This function creates a modeless dialog from a resource
HWND CreateDlg(unsigned int uiResID);

//  This function runs the dialog
WORD RunDlg(HWND hWnd);

private:

protected:
// This is the member callback function for the dialog window
virtual BOOL CALLBACK DlgProc(HWND m_hWnd, unsigned int uiMessage, WPARAM wParam, LPARAM lParam);

};

endif // BASE_DLG_H

==================================================================================================

CBaseDlg.cpp

include "CBaseDlg.h"

include "AboutDlg.h"

// Implementation of constructor
CBaseDlg::CBaseDlg()
{
}

// Implementation of destructor
CBaseDlg::~CBaseDlg()
{
}

// Create the dialog
HWND CBaseDlg::CreateDlg(unsigned int uiResID)
{
HWND hWnd = NULL;
// Create windows dialog (with a static dialog box procedure!)
// and pass the dialog window its 'this' pointer as LPARAM
// to get and check it when processing the WM_INITDIALOG message.
// This can be done by using 'CreateDialogParam'.
hWnd = CreateDialogParam( GetModuleHandle(NULL), // Instance of the application
MAKEINTRESOURCE(uiResID), // Resource ID of dialog
NULL, // Parent of dialog
DlgProcStatic, // Static dialog procedure
(LPARAM) this); // Additional parameter

return hWnd;
}

// Run the dialog
WORD CBaseDlg::RunDlg(HWND hWnd)
{
MSG msg;

if (hWnd == NULL) // Check if dialog window is created, otherwise return
{
return false;
}

// The usual message loop
while(GetMessage(&msg, NULL, 0, 0))
{
if ((IsWindow(hWnd) == false) || (IsDialogMessage(hWnd,&msg) == false))
{
// If window is not existing or the message is not intended for this dialog window
// Dispatch message to the appropriate window
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}

return (msg.wParam);
}

// Static dialog procedure
BOOL CALLBACK CBaseDlg::DlgProcStatic(HWND hWnd, unsigned int uiMessage, WPARAM wParam, LPARAM lParam)
{
CBaseDlg* pThis = NULL; // Make it NULL to check it later

// This is the first message is received at dialog window creation
if (uiMessage == WM_INITDIALOG) // If dialog window is created
{
// Get 'this' pointer information from LPARAM
pThis = (CBaseDlg) lParam;
// Associate it to the dialog window
SetWindowLong(hWnd, GWL_USERDATA, (long) pThis);
}
else
{
// Get associated dialog window instance
pThis = (CBaseDlg) GetWindowLong(hWnd, GWL_USERDATA);
}

if (pThis == NULL) // If pThis is not yet set (WM_INITDIALOG not processed)
{
return false; // Return an wait for the WM_INITDIALOG message, where it is set
}
else
{
// Call the member function with its 'this' pointer
return(pThis->DlgProc(hWnd, uiMessage, wParam, lParam));
}
}

// Implementation of member function (dialog box procedure) called by the static one
BOOL CALLBACK CBaseDlg::DlgProc(HWND hWnd, unsigned int uiMessage, WPARAM wParam, LPARAM lParam)
{
switch (uiMessage) // Handle messages
{
case WM_INITDIALOG: // Dialog is created
return 0;

case WM_COMMAND:    // Operate command
  switch (LOWORD(wParam))
  {
    case ID_BUTTON:
      // Open 'About Dialog'
      CAboutDlg AboutDlg;
      AboutDlg.RunDlg(AboutDlg.CreateDlg(IDD_ABOUT));
      break;
  }
  return 0;

case WM_CLOSE:
  DestroyWindow(hWnd);
  return 0;

case WM_DESTROY:    // Dialog window is destroyed
  PostQuitMessage(0);
  return 0;

default:
  return 0;

}
}

==================================================================================================

AboutDlg.h

ifndef ABOUT_DLG_H

define ABOUT_DLG_H

include "CBaseDlg.h"

class CAboutDlg : public CBaseDlg // Derive from dialog base class
{
public:
CAboutDlg(); // Use default constructor of base class
virtual ~CAboutDlg(); // Use default destructor of base class

private:
// This is the special member callback function for the 'About' dialog window
virtual BOOL CALLBACK DlgProc(HWND m_hWnd, unsigned int uiMessage, WPARAM wParam, LPARAM lParam);

protected:

};

endif // ABOUT_DLG_H

==================================================================================================

AboutDlg.cpp

include "AboutDlg.h"

// Implementation of constructor
CAboutDlg::CAboutDlg()
{
}

// Implementation of destructor
CAboutDlg::~CAboutDlg()
{
}

// Implementation of member function (dialog box procedure) called by the static one
BOOL CALLBACK CAboutDlg::DlgProc(HWND hWnd, unsigned int uiMessage, WPARAM wParam, LPARAM lParam)
{
switch (uiMessage) // Handle messages
{
case WM_INITDIALOG: // Dialog is created
return 0;

case WM_COMMAND:    // Operate command
  switch (LOWORD(wParam))
  {
    case ID_OK:
      DestroyWindow(hWnd);
      break;
  }
  return 0;

case WM_CLOSE:
  DestroyWindow(hWnd);
  return 0;

default:
  // Messages that are not handled are passed to the base dialog window procedure
  return CBaseDlg::DlgProc(hWnd, uiMessage, wParam, lParam);

}
}

[Jim W.]

First, what are you using for resource files ( .h and .rc )? (Also, you might want to make all the header guards consistent with the filenames....)

Second, after you have a working Project, use File > New > Template. (In Dev-C++ 4.9.9.0. Don't remember when that feature first appeared, though....)

-- Jim.

[Nobody/Anonymous]

Hi,

Thank you, it was pretty easy to create a template.

These are the resource files:

Resource.rc

include <windows.h> // Include windows stuff

include "Resource.h" // Include resource IDs

// The main dialog window
IDD_DLG DIALOG DISCARDABLE 0, 0, 140, 90
STYLE DS_MODALFRAME | DS_CENTER | WS_POPUP | WS_CAPTION | WS_SYSMENU | WS_VISIBLE
CAPTION "Dialog Wrapper Class Example"
FONT 8, "MS Sans Serif"
BEGIN
PUSHBUTTON "Click me", ID_BUTTON, 50, 38, 40, 14
END

// This could be the about dialog
IDD_ABOUT DIALOG DISCARDABLE 0, 0, 200, 100
STYLE DS_MODALFRAME | DS_CENTER | WS_POPUP | WS_CAPTION | WS_SYSMENU | WS_VISIBLE
CAPTION "Dialog"
FONT 8, "MS Sans Serif"
BEGIN
PUSHBUTTON "&Ok", ID_OK, 80, 73, 40, 14
LTEXT "By Thomas Henle", IDC_ABOUT_TEXT, 70, 20, 50, 8
END
==========================================

Resource.h

// Define here the IDs for your resources

define IDD_DLG 100

define IDD_ABOUT 101

define IDC_ABOUT_TEXT 1001

define ID_BUTTON 40001

define ID_OK 40002

I'm not shure if this is the correct way to have an message loop for all instances. I'd rather use 'DialogBox' instead of 'CreateDialogParam', but then I got some problems with the 'this' pointer in the static callback function.

Is there another way?

Tom

[Kip]

// Global static dialog proc through which all CWinApp objects pass through...
BOOL CALLBACK StaticDialogProcKernel(HWND hDlg, UINT msg, WPARAM wParam, LPARAM lParam)
{
// Variables...
HGLOBAL hMemory = 0;
CWinApp *pMemory = NULL;
CWinApp pDialogObject = NULL;

// Dialog just being created...
if(msg == WM_INITDIALOG)
{
    // Get object location...
    pDialogObject = (CWinApp *) lParam;

        // Failed...
        if(!pDialogObject)
        {
            // Tell user what's going on, then terminate...
            MessageBox(hDlg, "Dialog creation failed miserably...",
                       "Error", MB_OK | MB_ICONERROR);
            ExitProcess(1);
        }

    // Remember dialog handle...
    pDialogObject->hDialog = hDlg;

    // Bind object to dialog...

        // Allocate storage to hold address of object and lock it...
        hMemory = GlobalAlloc(GMEM_FIXED | GMEM_ZEROINIT, sizeof(pDialogObject));
        pMemory = (CWinApp **) GlobalLock(hMemory);

            // Failed...
            if(!pMemory)
            {
                // Kill it...
                EndDialog(pDialogObject->GetHandle(), -1);
                return FALSE;
            }

        // Initialize, then unlock...
       *pMemory = pDialogObject;
        GlobalUnlock(hMemory);

        // Bind, and check for error...
        if(!SetProp(hDlg, CWINAPP_PROPERTY_ID, hMemory))
        {
            // Kill it...
            EndDialog(pDialogObject->GetHandle(), -1);
            return FALSE;
        }
}

// Already bound, get object location...
pDialogObject = (CWinApp *) CWinApp::GetObject(hDlg);

    // No object handle to address received, abort to avoid seg fault...
    if(!pDialogObject)
        return FALSE;

// Pass window message to object's dialog procedure...
return pDialogObject->DialogProc(hDlg, msg, wParam, lParam);

}

=)

Kip

[Nobody/Anonymous]

Hi,

wow, that is a heavy piece of code for a beginner like me.
I hope I can sleep with that! :-)

You allocate memory to store the 'this' pointer.
You lock the memory and so got a pointer to that allocated memory.
You store the 'this' pointer to that memory.
You unlock the memory.

Now I found the 'SetProp' function in the API-Help but not the
'CWINAPP_PROPERTY_ID' constant.

So, to be honest, from that point I don't exactly know what's going on.

Why is this better than using 'SetWindowLong/GetWindowLong'?

Thank you very much!!

Tom

[Kip]

SetWindowLong / GetWindowLong access the user data section of the class, which is possibly shared by other programs / classes. SetProp lets us setup our own special area. CWINAPP_PROPERTY_ID is just a string constant. Replace with the name of your class.

Good luck =)

Kip

[Kip]

No problem. Enjoy =)

Kip

[Nobody/Anonymous]

Could you create a SDI with toolbar template for us ?

[Nobody/Anonymous]

What is SDI?

[Nobody/Anonymous]

I tried this and it works fine!

Once more, thank you!!!