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Using a progress dislog

stefi
stefi asked
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Last Modified: 2013-12-03
I'm using VC++ 4.0 and it has a progress component which I would like to use.
How can I make calls to it? How do I update it?
Source code for displaying and updating it is appreciated
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Commented:
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Commented:
Suppose you have a short loop of, say, 200 iterations.
You can init the progress bar as (min=0, max=200), set its initial position to (position=0) and its step to (step=1).
Inside the loop, just "step" the progress bar on each iteration.

Commented:
Of course, if you just want a control in a dialog, you may find it easier to use class wizard to create a control member variable for you.  Then you don't need to make SendMessage calls etc as you just use the CProgressCtrl class members.

I am assuming here that you are actually useing MFC (since you said you were talking about VC etc).

If not, the on-line help has sample SDK code calls eg..

Progress Bar Example

The following example shows how to use a progress bar to indicate the progress of a lengthy file-parsing operation. The example creates a progress bar and positions it along the bottom of the parent window's client area. The height of the progress bar is based on the height of the arrow bitmap used in a scroll bar. The range is based on the size of the file divided by 2048, which is the size of each "chunk" of data read from the file. The example also sets an increment and advances the current position of the progress bar by the increment after parsing each chunk.

  // ParseALargeFile - parses a large file and uses a progress bar to
  //   indicate the progress of the parsing operation.
  // Returns TRUE if successful, or FALSE otherwise.
  // hwndParent - parent window of the progress bar.
  // lpszFileName - name of the file to parse.
  //
  // Global variable
  //     g_hinst - instance handle
  extern HINSTANCE g_hinst;
 
  BOOL ParseALargeFile(HWND hwndParent, LPSTR lpszFileName)
  {
    RECT rcClient;  // client area of parent window
    int cyVScroll;  // height of scroll bar arrow
    HWND hwndPB;    // handle of progress bar
    HANDLE hFile;   // handle of file
    DWORD cb;       // size of file and count of bytes read
    LPCH pch;       // address of data read from file
    LPCH pchTmp;    // temporary pointer

    // Ensure that the common control DLL is loaded and create a
    // progress bar along the bottom of the client area of the
    // parent window. Base the height of the progress bar on
    // the height of a scroll bar arrow.
    InitCommonControls();
    GetClientRect(hwndParent, &rcClient);
    cyVScroll = GetSystemMetrics(SM_CYVSCROLL);
    hwndPB = CreateWindowEx(0, PROGRESS_CLASS, (LPSTR) NULL,
        WS_CHILD | WS_VISIBLE, rcClient.left,
        rcClient.bottom - cyVScroll,
        rcClient.right, cyVScroll,
        hwndParent, (HMENU) 0, g_hinst, NULL);
 
    // Open the file for reading, and retrieve the size of the file.
    hFile = CreateFile(lpszFileName, GENERIC_READ, FILE_SHARE_READ,
        (LPSECURITY_ATTRIBUTES) NULL, OPEN_EXISTING,
        FILE_ATTRIBUTE_NORMAL, (HANDLE) NULL);
 
    if (hFile == (HANDLE) INVALID_HANDLE_VALUE)
      return FALSE;
 
    cb = GetFileSize(hFile, (LPDWORD) NULL);
 
    // Set the range and increment of the progress bar.
    SendMessage(hwndPB, PBM_SETRANGE, 0, MAKELPARAM(0, cb / 2048));
    SendMessage(hwndPB, PBM_SETSTEP, (WPARAM) 1, 0);
 
    // Parse the file.
    pch = (LPCH) LocalAlloc(LPTR, sizeof(char) * 2048);
    pchTmp = pch;
    do {
        ReadFile(hFile, pchTmp, sizeof(char) * 2048, &cb,
            (LPOVERLAPPED) NULL);
        .
        . // Include here any code that parses the file.
        .
 
        // Advance the current position of the progress bar
        // by the increment.
        SendMessage(hwndPB, PBM_STEPIT, 0, 0);
    } while (cb);
    CloseHandle((HANDLE) hFile);
 
    DestroyWindow(hwndPB);
    return TRUE;
  }

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