My program increments counter once if the button is depressed, but it does not increment continuously if the button is held down. How do I acheive that?

Here’s a simple example code:

#include <Windows.h>

HINSTANCE g_hInst;

LRESULT CALLBACK WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
    static int n = 0;
    static HWND hEdit;
    static HWND hButton;

    switch (uMsg) {
    case WM_CREATE:
        hEdit = CreateWindow(L"EDIT", L"0", WS_CHILD | WS_VISIBLE | ES_CENTER | ES_READONLY, 100, 100, 100, 20, hWnd, (HMENU)1, g_hInst, NULL);
        hButton = CreateWindow(L"BUTTON", L"▴", WS_CHILD | WS_VISIBLE | BS_LEFT, 200 + 4, 100, 20, 20, hWnd, (HMENU)1, g_hInst, NULL);
        break;
    case WM_COMMAND: {
        HWND ctlHwnd = (HWND)lParam;
        int ctlId = LOWORD(wParam);
        int notificationCode = HIWORD(wParam);

        if (notificationCode == BN_CLICKED) {
            n++;
            wchar_t buf[40] = {0};
            wsprintf(buf, L"%d", n);
            SetWindowText(hEdit, buf);
        }
        break;
    }
    case WM_DESTROY:
        PostQuitMessage(EXIT_SUCCESS);
        break;
    default:
        return DefWindowProc(hWnd, uMsg, wParam, lParam);
    }
    return 0;
}

int WINAPI WinMain(
    HINSTANCE hInst,
    HINSTANCE hPrevInst,
    LPSTR lpCmdLine,
    int iCmdShow)
{
    g_hInst = hInst;

    WNDCLASS wndClass = {
        .style = CS_HREDRAW | CS_VREDRAW,
        .lpfnWndProc = WindowProc,
        .hInstance = hInst,
        .hIcon = LoadIcon(NULL, IDI_APPLICATION),
        .hCursor = LoadCursor(NULL, IDC_ARROW),
        .hbrBackground = (HBRUSH)GetStockObject(LTGRAY_BRUSH),
        .lpszMenuName = NULL,
        .lpszClassName = L"app",
    };
    if (!RegisterClass(&wndClass)) {
        OutputDebugString(L"Failed to register window classn");
        return EXIT_FAILURE;
    }
    if (!CreateWindow(
        L"app",
        L"Counter",
        WS_OVERLAPPEDWINDOW | WS_VISIBLE,
        0, 0,
        1280, 720,
        NULL, NULL,
        hInst, NULL))
    {
        OutputDebugString(L"Failed to create windown");
        return EXIT_FAILURE;
    }
    MSG msg = {};
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return (int)msg.wParam;
}