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How to Use Buddy Windows

  • Article

By setting other controls as buddy windows for a trackbar, you can automatically position those controls at the ends of the trackbar as labels.

The following illustration shows a horizontal and a vertical trackbar, both with static controls as buddy windows.

screen shot showing a dialog box with a horizontal trackbar and a vertical trackbar

What you need to know

Technologies

Prerequisites

  • C/C++
  • Windows User Interface Programming

Instructions

Use Buddy Windows

The following code example creates the buddy windows shown in the illustration.

void LabelTrackbarsWithBuddies(HWND hDlg)
{
    HWND hwndTrackbar;
    HWND hwndBuddy;
    
    const int staticWidth   = 50;
    const int staticHeight  = 20;

//======================================================
// For horizontal Trackbar.

    hwndTrackbar = GetDlgItem(hDlg, IDC_SLIDER1);

    hwndBuddy = CreateWindowEx(0, L"STATIC", L"Left", SS_RIGHT | WS_CHILD | WS_VISIBLE, 
                                    0, 0, staticWidth, staticHeight, hDlg, NULL, g_hInst, NULL);
                                    
    SendMessage(hwndTrackbar, TBM_SETBUDDY, (WPARAM)TRUE, (LPARAM)hwndBuddy);
    
    //-------------------------------------------------

    hwndBuddy = CreateWindowEx(0, L"STATIC", L"Right", SS_LEFT | WS_CHILD | WS_VISIBLE, 
                               0, 0, staticWidth, staticHeight, hDlg, NULL, g_hInst, NULL);
                                
    SendMessage(hwndTrackbar, TBM_SETBUDDY, (WPARAM)FALSE, (LPARAM)hwndBuddy);
    
//======================================================    
// For vertical Trackbar.
    
    hwndTrackbar = GetDlgItem(hDlg, IDC_SLIDER2);

    hwndBuddy = CreateWindowEx(0, L"STATIC", L"Top", SS_CENTER | WS_CHILD | WS_VISIBLE, 
                               0, 0, staticWidth, staticHeight, hDlg, NULL, g_hInst, NULL);
                               
    SendMessage(hwndTrackbar, TBM_SETBUDDY, (WPARAM)TRUE, (LPARAM)hwndBuddy);

    //-------------------------------------------------

    hwndBuddy = CreateWindowEx(0, L"STATIC", L"Bottom", SS_CENTER | WS_CHILD | WS_VISIBLE, 
                               0, 0, staticWidth, staticHeight, hDlg, NULL, g_hInst, NULL);
                               
    SendMessage(hwndTrackbar, TBM_SETBUDDY, (WPARAM)FALSE, (LPARAM)hwndBuddy);
}

Remarks

IDC_SLIDER1 and IDC_SLIDER2 are trackbars created in the resource editor.

Using Trackbar Controls