windows sdk编程禁止改变窗体大小

#include <windows.h>

/*消息处理函数声明*/
HRESULT CALLBACK WindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{

     HWND hwnd;
     MSG message;
    WNDCLASS wndClass;

    char szClassName[] = "MainWindonClass";//窗体类名

    DWORD dwStyle = WS_OVERLAPPEDWINDOW & ~WS_MAXIMIZEBOX &~ WS_THICKFRAME; //设置窗体样式 ,禁止改变窗体大小 

    /*窗口类设置*/
    wndClass.style = CS_DBLCLKS;
    wndClass.lpfnWndProc=WindowProc;
    wndClass.cbClsExtra=;
    wndClass.cbWndExtra=;
    wndClass.hInstance=hInstance;
    wndClass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
    wndClass.hCursor=LoadCursor (NULL, IDC_ARROW);
    wndClass.hbrBackground=(HBRUSH) GetStockObject (WHITE_BRUSH);
    wndClass.lpszMenuName=NULL;
    wndClass.lpszClassName=szClassName;

    /*窗口类注册*/
    if( RegisterClass(&wndClass) ==  )
        return ;//表示注册失败 

    /*创建窗体*/
    hwnd = CreateWindow(szClassName,
                        "禁止改变窗体大小",
                        dwStyle,//设置窗体样式
                        ,
                        ,
                        ,
                        ,
                        NULL,
                        NULL,
                        hInstance,
                        NULL
                        );
     if(hwnd == )
     {
         MessageBox(NULL,"窗体创建失败!","失败",MB_OK);
         return ;
    }

    /* 显示窗体 */
    ShowWindow(hwnd,nCmdShow);

    while (GetMessage (&message, NULL, , ))
    {
        TranslateMessage(&message);//翻译
        DispatchMessage(&message);//发送消息
    } 

    return message.wParam;
}

/*消息处理*/
LRESULT CALLBACK WindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
        case WM_DESTROY:
            PostQuitMessage ();
            break;
        default:
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return ;
}