#include <windows.h>

 #include "resource.h"

 LRESULT CALLBACK MyWndProc(  HWND hwnd,      // handle to window

   UINT uMsg,      // message identifier

   WPARAM wParam,  // first message parameter

   LPARAM lParam   // second message parameter

   );

 int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd )

 {

     TCHAR szAppName[] = TEXT("IconDemo");

     WNDCLASS wnd;

     HWND hwnd;

     MSG msg;

     wnd.style = CS_HREDRAW | CS_VREDRAW; //水平或垂直改变窗口都被重绘 与MyWndProc的WM_PAINT消息关联

     wnd.lpfnWndProc = MyWndProc;

     wnd.cbClsExtra = ;

     wnd.cbWndExtra = ;

     wnd.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON));

     wnd.hCursor = LoadCursor(NULL, IDC_ARROW);

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

     wnd.lpszMenuName = NULL;

     wnd.lpszClassName = szAppName; //窗口类标识,用在CreateWindow的第一个参数

     wnd.hInstance = hInstance;

     if(!RegisterClass(&wnd))

     {

         MessageBox(NULL, TEXT("无法创建窗口"), TEXT("ERROR"), MB_OK|MB_ICONERROR);

         return ;

     }

     hwnd = CreateWindow(szAppName, TEXT("Hello"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL); //第二个参数为窗口标题

     ShowWindow(hwnd, nShowCmd);

     UpdateWindow(hwnd);

     while (GetMessage(&msg, NULL, , ))

     {

         TranslateMessage(&msg);

         DispatchMessage(&msg);

     }

     return ;

 }

 LRESULT CALLBACK MyWndProc(  HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)

 {

     HDC hdc; //定义设备环境句柄

     PAINTSTRUCT ps; //绘制结构

     static HICON hIcon;

     static int cxIcon, cyIcon, cxClient, cyClient;

     HINSTANCE hInstance;

     int x, y;

     switch(uMsg)

     {

     case WM_CREATE:

     {

         hInstance = ((LPCREATESTRUCT) lParam)->hInstance;//WM_CREATE消息的lParam参数是一个CREATESTRUCT结构的指针,包含hInstance.

         hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON));

         cxIcon = GetSystemMetrics(SM_CXICON); //获取图标大小,上一条LoadIcon关联

         cyIcon = GetSystemMetrics(SM_CYICON);

         return ;

     }

     break;

     case WM_PAINT:

     {

         hdc = BeginPaint(hwnd, &ps);

         for (y = ; y < cyClient; y += cyIcon)

         {

             for (x = ; x < cxClient; x += cxIcon)

             {

                 DrawIcon(hdc, x, y, hIcon); //绘制

             }

         }

         EndPaint(hwnd, &ps);

     }

     break;

     case WM_SIZE:

     {

         cxClient = LOWORD(lParam);

         cyClient = HIWORD(lParam);

     }

     break;

     case WM_DESTROY:

         PostQuitMessage();

         return ;

     }

     return DefWindowProc(hwnd, uMsg, wParam, lParam);

 }