Hello

Can you help me figure out how to use WM_DRAWITEM to change a buttons
colour

This does nothing, when I though it would change the buttons colour:

case UBP_CONTROLBKCOL:
                   {
                        HWND stBk = GetDlgItem( hwnd,
LOWORD(wParam) );
                        HBRUSH newBrush = CreateSolidBrush( colour );
                        SetClassLongPtr( stBk, GCLP_ HBRBACKGROUND,
(LONG_PTR)&newBrush );

}
break;


My Main program that compiles & works, except the button colour does
not change?

/*
  Application:
*/

#include <windows.h>
#include <windowsx.h>
#include <stdio.h>
#include <cmath>
#include <vector>
#include <string>
#include <cstdlib>

using namespace std;

#define UBP_CONTROLBKCOL 50001

static HINSTANCE gInstance;
UINT controlMsgs[] = {};
COLORREF colour = RGB(0,0,0);


// Functions List //
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM
lParam);
bool openColourDialog(HWND hwnd, UINT id);


LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM
lParam)
{

    switch(msg)
    {
        case WM_CREATE:
        {
             // Create GUI

             HWND stBkColour        =
CreateWindowEx(0,"Static","Background Colour",
                                           WS_BORDER|WS_CHILD|
WS_VISIBLE,
 
18,20,120,20,hwnd,NULL,gInstance,
                                           NULL);

             HWND bkColour          =
CreateWindowEx(0,"Button","",WS_BORDER|WS_CHILD|
                                                     WS_VISIBLE|
BS_OWNERDRAW,150,15,50,
                                                     28,hwnd,
(HMENU)UBP_CONTROLBKCOL,
                                                     gInstance,NULL);
        }
        break;
        case WM_COMMAND:
         {
              // Open Colour dialog to change button colour

              switch(LOWORD(wParam))
              {
                   case UBP_CONTROLBKCOL:
                   {
                        openColourDialog(hwnd,LOWORD(wParam));
                   }
                   break;
                   default:
                   break;
              }
         }
        break;
        case WM_DRAWITEM:
         {
              // Draw button background colour

              switch(LOWORD(wParam))
              {
                   case UBP_CONTROLBKCOL:
                   {
                        HWND stBk = GetDlgItem( hwnd,
LOWORD(wParam) );
                        HBRUSH newBrush = CreateSolidBrush( colour );
                        SetClassLongPtr( stBk, GCLP_HBRBACKGROUND,
(LONG_PTR)&newBrush );
                        // I get an ERROR in the above line
                        // Error = 'GCLP undeclared(first use of this
function'
                        // So my program wont compile, is this the way
I can change
                        // the colour of a button?
                   }
                   break;
                   default:
                   break;
              }
         }
         break;
        case WM_CLOSE:
            DestroyWindow(hwnd);
        break;
        case WM_DESTROY:
            PostQuitMessage(0);
        break;
        default: return DefWindowProc(hwnd, msg, wParam, lParam);
        break;
    }
}

bool openColourDialog(HWND hwnd, UINT id)
{
   // Post: Open colour dialog to allow user to pick a new colour for
updateBox
   //       control attribute

   CHOOSECOLOR cc;                 // common dialog box structure
   static COLORREF acrCustClr[16]; // array of custom colors
   static DWORD rgbCurrent;        // initial color selection

   // Initialize CHOOSECOLOR
   ZeroMemory(&cc, sizeof(cc));
   cc.lStructSize = sizeof(cc);
   cc.hwndOwner = hwnd;
   cc.lpCustColors = (LPDWORD) acrCustClr;
   cc.rgbResult = rgbCurrent;
   cc.Flags = CC_FULLOPEN | CC_RGBINIT;

   if (ChooseColor(&cc)==TRUE)
   {
       rgbCurrent = cc.rgbResult;
       colour = rgbCurrent;
       SendMessage(hwnd,WM_DRAWITEM,(WPARAM)id,0); // Send message to
change button colour
       return true;
   }

   return false;
}


int WINAPI WinMain(HINSTANCE gInstance, HINSTANCE hPrevInstance, LPSTR
lpCmdLine, int nCmdShow)
{
    WNDCLASSEX wc;
    HWND hwnd;
    MSG Msg;

    //Step 1: Registering the Window Class
    wc.cbSize        = sizeof(WNDCLASSEX);
    wc.style         = 0;
    wc.lpfnWndProc   = WndProc;
    wc.cbClsExtra    = 0;
    wc.cbWndExtra    = 0;
    wc.hInstance     = gInstance;
    wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(DKGRAY_BRUSH);
    wc.lpszMenuName  = NULL;
    wc.lpszClassName = "Custom Class";
    wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);

    // if registration of main class fails
    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Window Registration Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    // Step 2: Creating the Window
    hwnd = CreateWindowEx(
        WS_EX_CLIENTEDGE,
        "Custom Class",
        "App Name",
        WS_CAPTION|WS_MINIMIZEBOX|WS_VISIBLE|WS_OVERLAPPED|WS_SYSMENU,
        CW_USEDEFAULT, CW_USEDEFAULT, 600, 500,
        NULL, NULL, gInstance, NULL);

    if(hwnd == NULL)
    {
        MessageBox(NULL, "Window Creation Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

    // Step 3: The Message Loop
    while(GetMessage(&Msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return Msg.wParam;
}

On 14/05/2010 10:26, Jimbo wrote:
> Hello
>
> Can you help me figure out how to use WM_DRAWITEM to change a buttons
> colour
>
> This does nothing, when I though it would change the buttons colour:
>
> case UBP_CONTROLBKCOL:
>                     {
>                          HWND stBk = GetDlgItem( hwnd,
> LOWORD(wParam) );
>                          HBRUSH newBrush = CreateSolidBrush( colour );
>                          SetClassLongPtr( stBk, GCLP_ HBRBACKGROUND,
> (LONG_PTR)&newBrush );
>
> }
> break;
>
>
> My Main program that compiles&  works, except the button colour does
> not change?

Is it a themed button (Xp, Vista, 7)?
You can't change just the colour as that is drawn by the theme.
You will need to completely draw it yourself if you want it to look 
different to everything else on the system.

-- 
Dee Earley (dee.earley@icode.co.uk)
i-Catcher Development Team

iCode Systems

(Replies direct to my email address will be ignored.
Please reply to the group.)

http://www.alsprogrammingresource.com/win32_tutorials.html

Scroll down to. . . . .

Color Buttons
Example Program
Source Code Listing