WIN32自绘按钮，求大神解答问题

以下是我自己写的Button类，但是自绘效果是有了，点击按钮没反应，是不是主窗口没收到消息呢？怎么解决
//创建按钮
void cbutton::CreateButton(HWND hWnd, HINSTANCE hInstance, int hB_x, int hB_y, int hB_w, int hB_h, int ID)
{
    //创建按钮
    hButton = CreateWindow(
        L"button",      
        L" ",            
        WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON | BS_OWNERDRAW,
        hB_x,   
        hB_y,
        hB_w,
        hB_h,
        hWnd,
        (HMENU) ID,
        hInstance,
        NULL);

    w = hB_w;     
    h = hB_y;

    SetWindowLong(hButton, GWL_WNDPROC, (LONG)ButtonProc);
}
//（静态）按钮窗口过程处理函数
LRESULT cbutton::ButtonProc(HWND hbwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    cbutton *athis = (cbutton*)GetWindowLong(hbwnd, GWL_USERDATA);
    athis->hButton=hbwnd;
    switch (msg)
    {
        PAINTSTRUCT ps;
        HBITMAP hb;

    case WM_DESTROY:
   
        PostQuitMessage(0);
        break;

    case WM_PAINT:
        
        b_hdc = BeginPaint(hbwnd, &ps);      //开始绘图

        b_mdc = CreateCompatibleDC(b_hdc);   //兼容DC
        
        //加载图片
        hb = (HBITMAP)LoadImage(NULL, FileName, IMAGE_BITMAP,
            0, 0, LR_LOADFROMFILE);

        SelectObject(b_mdc, hb);
        
        //贴图
        BitBlt(b_hdc, 0, 0, w ,h, b_mdc, 0, 0, SRCCOPY);
        EndPaint(hbwnd, &ps);              //结束绘图
        
        w = 0;
        h = 0;
        DeleteObject(b_hdc);
        DeleteObject(b_mdc);
        memset(FileName, '\0', sizeof(FileName));

        break;
   
    }
    return DefWindowProc(hbwnd,msg,wParam,lParam);
}