Win32 Topics: Calling a Dialog Box From an SDI

	Calling a Dialog Box From an SDI

Introduction

A Single Document Interface (SDI) is the type of application that presents a frame-based window equipped with a title bar, a menu, and thick borders. In most cases the one-frame window is enough to support the application.

To provide support and various options to the frame of an SDI, you can add other dependent windows such as dialog boxes. When such a dialog box is needed, you can provide a menu item that the user would use to display the dialog box. Just as you can add one dialog box to an application, in the same way, you can add as many dialog boxes as you judge necessary to your SDI application and provide a way for the user to display them.

To display a dialog from an SDI, the easiest and most usual way consists of creating a menu item on the main menu. When implementing the event of the menu item, as normally done in C++, in the source file of the class that would call it, include the header file of the dialog box. In the event that calls the dialog box, first declare a variable based on the name of the class of the dialog box.

Practical Learning: Calling a Dialog Box From an SDI

Start your programming environment. For this example, we will use Borland C++BuilderX.
Therefore, start Borland C++BuilderX and, on the main menu, click File -> New...
In the Object Gallery dialog box, click New GUI Application and click OK
In the New GUI Application Project Wizard - Step 1 of 3, in the Directory edit box of the Project Settings section, type the path you want. Otherwise, type
C:\Programs\Win32 Programming
In the Name edit box, type SDI1
Click Next
In the New GUI Application Project Wizard - Step 2 of 3, accept the defaults and click Next
In the New GUI Application Project Wizard - Step 3 of 3, click the check box under Create
Select Untitled under the Name column header. Type Exercise to replace the name and press Tab
Click Finish
To create a resource header file, on the main menu, click File -> New File...
In the Create New File dialog box, in the Name, type Resource
In the Type combo box, select h, and click OK

In the file, type:

#define IDR_MAIN_MENU     1001
#define IDM_FILE_EXIT     1002
#define IDM_HELP_ABOUT    1003

#define IDD_ABOUTDLGBOX   1010

To create a resource script, on the main menu, click File -> New File...
In the Create New File dialog box, in the Name, type SDI1
In the Type combo box, select rc, and click OK

In the file, type:

#include "Resource.h"

// Main Menu
IDR_MAIN_MENU MENU
BEGIN
  POPUP "&File"
  BEGIN
    MENUITEM "E&xit",      IDM_FILE_EXIT
  END
  POPUP "&Help"
  BEGIN
    MENUITEM "&About...",  IDM_HELP_ABOUT
  END
END

// Dialog Box: About
IDD_ABOUTDLGBOX DIALOGEX 0, 0, 184, 81
STYLE DS_SETFONT | DS_MODALFRAME | DS_FIXEDSYS | WS_POPUP | WS_CAPTION |
    WS_SYSMENU
CAPTION "About SDI1"
FONT 8, "MS Shell Dlg"
BEGIN
    DEFPUSHBUTTON   "OK",IDOK,127,7,50,16,WS_GROUP
END

Display the Exercise.cpp file and change it as follows:

#include <windows.h>
#include "Resource.h"

#ifdef __BORLANDC__
  #pragma argsused
#endif
//---------------------------------------------------------------------------
HINSTANCE hInst;
const char *ClsName = "CallingDlg";
const char *WndName = "Calling a Dialog Box From an SDI";
//---------------------------------------------------------------------------
LRESULT CALLBACK WndProcedure(HWND hWnd, UINT uMsg,
                              WPARAM wParam, LPARAM lParam);
LRESULT CALLBACK DlgProc(HWND hWndDlg, UINT Msg,
                         WPARAM wParam, LPARAM lParam);
//---------------------------------------------------------------------------
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                     LPSTR lpCmdLine, int nCmdShow )
{
        MSG        Msg;
        HWND       hWnd;
        WNDCLASSEX WndClsEx;

        // Create the application window
        WndClsEx.cbSize        = sizeof(WNDCLASSEX);
        WndClsEx.style         = CS_HREDRAW | CS_VREDRAW;
        WndClsEx.lpfnWndProc   = WndProcedure;
        WndClsEx.cbClsExtra    = 0;
        WndClsEx.cbWndExtra    = 0;
        WndClsEx.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
        WndClsEx.hCursor       = LoadCursor(NULL, IDC_ARROW);
        WndClsEx.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
        WndClsEx.lpszMenuName  = MAKEINTRESOURCE(IDR_MAIN_MENU);
        WndClsEx.lpszClassName = ClsName;
        WndClsEx.hInstance     = hInstance;
        WndClsEx.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);

        // Register the application
        RegisterClassEx(&WndClsEx);
        hInst = hInstance;

        // Create the window object
        hWnd = CreateWindow(ClsName,
                          WndName,
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT,
                          CW_USEDEFAULT,
                          CW_USEDEFAULT,
                          CW_USEDEFAULT,
                          NULL,
                          NULL,
                          hInstance,
                          NULL);

        // Find out if the window was created
        if( !hWnd ) // If the window was not created,
                return 0; // stop the application

        // Display the window to the user
        ShowWindow(hWnd, SW_SHOWNORMAL);
        UpdateWindow(hWnd);

        // Decode and treat the messages
        // as long as the application is running
        while( GetMessage(&Msg, NULL, 0, 0) )
        {
             TranslateMessage(&Msg);
             DispatchMessage(&Msg);
        }

        return Msg.wParam;
}
//---------------------------------------------------------------------------
LRESULT CALLBACK WndProcedure(HWND hWnd, UINT Msg,
                           WPARAM wParam, LPARAM lParam)
{
    switch(Msg)
    {
    case WM_COMMAND:
        switch(LOWORD(wParam))
        {
        case IDM_FILE_EXIT:
            PostQuitMessage(WM_QUIT);
            break;
        case IDM_HELP_ABOUT:
            DialogBox(hInst,
                      MAKEINTRESOURCE(IDD_ABOUTDLGBOX),
                      hWnd,
                      reinterpret_cast<DLGPROC>(DlgProc));
            break;
        }
        return 0;

    // If the user wants to close the application
    case WM_DESTROY:
        // then close it
        PostQuitMessage(WM_QUIT);
        break;
    default:
        // Process the left-over messages
        return DefWindowProc(hWnd, Msg, wParam, lParam);
    }
    // If something was not done, let it go
    return 0;
}
//---------------------------------------------------------------------------
LRESULT CALLBACK DlgProc(HWND hWndDlg, UINT Msg, WPARAM wParam, LPARAM lParam)
{
        switch(Msg)
        {
        case WM_INITDIALOG:
                return TRUE;

        case WM_COMMAND:
                switch(wParam)
                {
                case IDOK:
                        EndDialog(hWndDlg, 0);
                        return TRUE;
                }
                break;
        }

        return FALSE;
}
//---------------------------------------------------------------------------

Test the application


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