Windows API一日一练(9)EndDialog,DestroyWindow函数

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
 MSG msg;
 HACCEL hAccelTab;

 LoadString(hInstance, IDS_SZCLASS, szClass, MAX_LOADSTRING); //加载资源里的字符串
 LoadString(hInstance, IDS_SZTITLE, szTitle, MAX_LOADSTRING); //加载资源里的字符串

 MyRegisterClass(hInstance);
 if(!InitInstance(hInstance, SW_SHOWNORMAL))
 {
  return FALSE;
 }
 hAccelTab = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_TESTWIN));

  while (GetMessage(&msg, NULL, 0, 0)) //获取所有窗口的消息
  {
  TranslateMessage(&msg); //调用函数TranslateMessage作消息转换工作
  
  DispatchMessage(&msg);  //调用函数DispatchMessage发送消息
  }

 return msg.wParam;
}

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
 hinst = hInstance;
 HWND hwnd;

 hwnd = CreateWindow(szClass, szTitle , WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
  CW_USEDEFAULT, NULL, NULL, hInstance, NULL);
 
 if (!hwnd)
 {
  return FALSE;
 }

 ShowWindow(hwnd, nCmdShow);
 UpdateWindow(hwnd);

 return TRUE;

}

ATOM MyRegisterClass(HINSTANCE hInstance)
{
 WNDCLASSEX wcex;
 
 
wcex.cbSize = sizeof(WNDCLASSEX);  
 
 wcex.style = CS_HREDRAW | CS_VREDRAW; 

 wcex.lpfnWndProc = MyProc;   

 wcex.cbClsExtra = 0;    

 wcex.cbWndExtra = 0;     

 wcex.hInstance = hInstance;   

 wcex.hIcon = LoadIcon(NULL, MAKEINTRESOURCE(IDI_MAIN));
 wcex.hCursor = LoadCursor(NULL, IDC_ARROW);

 wcex.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); 

 wcex.lpszMenuName = MAKEINTRESOURCE(IDR_MAIN); 

 wcex.lpszClassName = szClass;
 
 wcex.hIconSm = NULL;

 return RegisterClassEx(&wcex);
}

LRESULT CALLBACK MyProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
 PAINTSTRUCT ps;
 HDC hdc;

 switch(uMsg)
 {
 case WM_COMMAND:
  switch(LOWORD(wParam))
  {
  case IDM_ABOUT:
   DialogBox(hinst, MAKEINTRESOURCE(IDD_ABOUT), hwnd, DialogProc);  //显示对话框
   break;
  default:
   return DefWindowProc(hwnd, uMsg, wParam, lParam);
  }
  break;
  case WM_CLOSE: 
   DestroyWindow(hwnd);  //当收到退出命令的消息，就调用函数DestroyWindow，然后它发出消息WM_DESTROY
   break;
  case WM_DESTROY:
   PostQuitMessage(0); //调用函数PostQuitMessage来处理退出应用程序
   break;
  case WM_PAINT:
   RECT rect;
   GetClientRect(hwnd,&rect);
   hdc = BeginPaint(hwnd,&ps); //调用函数BeginPaint

   DrawText(hdc,TEXT("Hell Word"),-1, &rect, DT_VCENTER | DT_TOP);

   EndPaint(hwnd,&ps); //调用函数EndPaint
  break;
 default:
  return DefWindowProc(hwnd, uMsg, wParam, lParam);
 }
}

// 处理对话框消息

INT_PTR CALLBACK DialogProc(
  HWND hwndDlg,  // handle to dialog box
  UINT uMsg,     // message
  WPARAM wParam, // first message parameter
  LPARAM lParam  // second message parameter
)
{
 UNREFERENCED_PARAMETER(lParam);
 switch(uMsg)
 {
 case WM_COMMAND:
  if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
  {
   EndDialog(hwndDlg,LOWORD(wParam)); //用EndDialog关闭对话框
   return TRUE;
  }
  break;
 default:
  return FALSE;
 }
 
}