Trackbar Control Example demo

To create a Trackbar control specify TRACKBAR_CLASS as the window class and register the class by specifying the ICC_BAR_CLASSES bit flag in the accompanying INITCOMMONCONTROLSEX structure.

The TBS_AUTOTICKS style creates a tick mark for each increment in its range of values. Setting other controls as buddy window for the trackbar, means descriptive labels can be placed at either end of the trackbar. When Trackbar slider is moved, the parent window receives the WM_HSCROLL message.

#define _WIN32_WINNT 0x0501
#include <windows.h>
#include <commctrl.h>

#pragma comment(lib, "comctl32.lib")

#define LEFTLABEL     1
#define RIGHTLABEL    2
#define COUNTLABEL    3
#define TRACKBARCTL   4

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

void CreateControls(HWND);
void UpdateLabel();

HWND hTrackBar;
HWND hTrackLabel;

// Main program
int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine,
                   int nCmdShow)
{
    HWND hwnd;
    MSG msg;
    WNDCLASS wc;
    // Register window class
    wc.style = 0;
    wc.lpfnWndProc = WndProc;
    wc.cbClsExtra = 0;
    wc.cbWndExtra = 0;
    wc.hInstance = hInstance;
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_3DFACE + 1);
    wc.lpszMenuName = NULL;
    wc.lpszClassName = TEXT("TrackbarClass");
    RegisterClass(&wc);

    // Create main window
    hwnd = CreateWindow(
        TEXT("TrackbarClass"),
        TEXT("Trackbar Control Demo"),
        WS_OVERLAPPEDWINDOW | WS_VISIBLE,
        100,
        100,
        350,
        180,
        NULL,
        NULL,
        hInstance,
        NULL);

    // Message loop
    while(GetMessage(&msg,NULL,0,0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}

// Window procedure
LRESULT CALLBACK WndProc(HWND hwnd,
                         UINT msg,
                         WPARAM wParam,
                         LPARAM lParam)
{
    switch(msg)
    {
    case WM_CREATE:
        CreateControls(hwnd);
        break;

    // Trackbar sends this when the slider moves
    case WM_HSCROLL:
        UpdateLabel();
        break;

    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hwnd,msg,wParam,lParam);
    }
    return 0;
}

// Create controls
void CreateControls(HWND hwnd)
{
    INITCOMMONCONTROLSEX icex;
    // Load trackbar common control
    icex.dwSize = sizeof(INITCOMMONCONTROLSEX);
    icex.dwICC = ICC_BAR_CLASSES;
    InitCommonControlsEx(&icex);
    // Left value label
    CreateWindow(
        TEXT("STATIC"),
        TEXT("0"),
        WS_CHILD | WS_VISIBLE,
        10,
        50,
        20,
        20,
        hwnd,
        (HMENU)LEFTLABEL,
        NULL,
        NULL);
        
    // Right value label
    CreateWindow(
        TEXT("STATIC"),
        TEXT("100"),
        WS_CHILD | WS_VISIBLE,
        220,
        50,
        40,
        20,
        hwnd,
        (HMENU)RIGHTLABEL,
        NULL,
        NULL);
        
    // Display current value
    hTrackLabel = CreateWindow(
        TEXT("STATIC"),
        TEXT("0"),
        WS_CHILD | WS_VISIBLE | WS_BORDER,
        150,
        100,
        50,
        25,
        hwnd,
        (HMENU)COUNTLABEL,
        NULL,
        NULL);

    // Create trackbar
    hTrackBar = CreateWindow(
        TRACKBAR_CLASS,
        TEXT(""),
        WS_CHILD |
        WS_VISIBLE |
        TBS_AUTOTICKS |
        TBS_HORZ,
        40,
        45,
        170,
        40,
        hwnd,
        (HMENU)TRACKBARCTL,
        NULL,
        NULL);

    // Set minimum and maximum values
    SendMessage(
        hTrackBar,
        TBM_SETRANGE,
        TRUE,
        MAKELONG(0,100));

    // Set page movement
    SendMessage(
        hTrackBar,
        TBM_SETPAGESIZE,
        0,
        10);

    // Add tick marks every 10
    SendMessage(
        hTrackBar,
        TBM_SETTICFREQ,
        10,
        0);
        
    // Set starting position
    SendMessage(
        hTrackBar,
        TBM_SETPOS,
        TRUE,
        0);
}

// Update displayed value
void UpdateLabel()
{
    long position;
    TCHAR buffer[20];
    position = SendMessage(
        hTrackBar,
        TBM_GETPOS,
        0,
        0);
    wsprintf(
        buffer,
        TEXT("%ld"),
        position);
    SetWindowText(
        hTrackLabel,
        buffer);
}