Thread: progress bars with Win32 API

im trying to set up a simple progress bar in windows 98 using the win32 API, but im not having much luck. this is a simplified version of my code.

Code:

#include <windows.h>
#include <commctrl.h>

HINSTANCE g_hinst;

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
  HWND hwndPB;
  RECT rcClient;
  int cyVScroll;
  switch(msg)
  {
    case WM_CREATE:
      GetClientRect(hwnd, &rcClient);
      cyVScroll = GetSystemMetrics(SM_CYVSCROLL);

      hwndPB = CreateWindowEx(0, PROGRESS_CLASS
                             (LPSTR)NULL, WS_CHILD | WS_VISIBLE, 
                           rcClient.left, 
	           rcClient.bottom - cyVScroll, 
	           rcClient.right, cyVScroll, 
	           hwnd, (HMENU) 0, g_hinst, NULL);

      SendMessage(hwndPB, PBM_SETRANGE, 0, MAKELPARAM
                             (0,100));
      SendMessage(hwndPB, PBM_SETPOS, (WPARAM)33, 0);
      break;
  }
  return 0;
}

what is the problem here? according to a reference i downloaded this should all work fine. all i want to do is put a progress bar in a window.

>>what is the problem here?

I dont know. What is the problem?

Seeing as how I dont feel like trying to compile that, nor do I wish to scour it for anything at all that may be wrong, it would be most helpful if you actually told us what the problem was. Does it not compile? What errors? What warnings? If it does compile, what does it do?

yeah, i didn't really state the problem did i.

well, the problem is that nothing comes up in the window, no progress bar, nothing. thats all that i can tell.

The code to create the progress bar should probably go outside the window procedure. You can't put it in the WM_CREATE case, because the parent window hasn't been created yet. There may be another msg you could use instead of WM_CREATE.

i had tried to use InitCommonControls() before, but it gave me these weird compiling error messages. hold on a sec ill just test it...

actually, its linker errors:

api.obj : error LNK2001: unresolved external symbol __imp__InitCommonControls@0
Debug/win32.exe : fatal error LNK1120: 1 unresolved externals

in this case, i put InitCommonControls() in WM_CREATE in WndProc just before running CreateWindowEx().

the same stuff happens if i insert it in WinMain().

when i put in InitCommonControlsEx() it says i have too few parameters.

what do i do?

You have not linked with comctl32.lib (msvc6: project->settings->'link tab', project options edit control; just put comctl32.lib in there with the other libs).

Ken,

I ran the code above with the progress bar creation in the WM_CREATE case, and the progress bar never came up.

I tried moving the code to the main program after window creation, and it came up fine.

Do you have any ideas why it won't work in the WM_CREATE case ? Or can you supply some code that will work ?

I would like to get it to work in the WM_CREATE. Like you said, it makes more sense to put it there.

Thanks,
swoopy

Shouldn't this be posted in the Windows programming board?...

KF is right about WM_CREATE. there is no better place to create child windows. Something must be wrong with the way you are doing it int the WM_CREATE case.

>>Or can you supply some code that will work ?<<

[Warning: shameless plug] Creating Common Controls etc [/shameless plug]

>>Shouldn't this be posted in the Windows programming board?...<<

Said it already but I quite agree; if I were a regular c++ boarder I would be alarmed by the insidious creep of the dreaded 'winscum'.

I put a message box right after this line:

Code:

      hwndPB = CreateWindowEx(0, PROGRESS_CLASS
                             (LPSTR)NULL, WS_CHILD | WS_VISIBLE, 
                           rcClient.left, 
	           rcClient.bottom - cyVScroll, 
	           rcClient.right, cyVScroll, 
	           hwnd, (HMENU) 0, g_hinst, NULL);

to print the value of hwndPB, and it was zero. I guess it never created the progress bar for some reason.

if I were a regular c++ boarder I would be alarmed by the invidious creep of the dreaded 'winscum'.

hehe ... have you read any of the newsgroups like comp.lang.cpp? They go ballistic if anything gets platform specific.

thanks Ken Fitlike. your site kicks arse
it would have to be the smallest and simplest site ive been to, but the only one which told me something useful! i finally got the bar to work. next step though, and i know i should start a new thread, but how can i make it go up and down? ie, is there a timing control i can use?

cheers