改变鼠标样式可以使用SetClassLong函数
HCURSOR hcur = LoadCursor(NULL, IDC_CROSS); //加载系统自带鼠标样式
HWND hwnd = GetHWnd(); // 获取绘图窗口句柄
SetClassLong(hwnd, GCL_HCURSOR, (long)hcur);
那么如果想要把鼠标样式设置为自定义的鼠标样式（.cur）呢？
HWND hwnd = GetHWnd(); // 获取绘图窗口句柄
SetClassLong(hwnd, GCL_HCURSOR, (long)LoadCursorFromFile("mouse.cur"));