#include<windows.h>int WINAPI WinMain(HINSTANCE,HINSTANCE,LPSTR,int);LRESULT WINAPI WndProc(HWND,UINT,WPARAM,LPARAM);// WinMain 函数int WINAPI WinMain (HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nCmdShow){HWND hWnd; // 主窗口句柄MSG msg; // 窗口消息WNDCLASS wc; // 窗口类if (!hPrevInstance){// 填充窗口类信息wc.style=CS_HREDRAW|CS_VREDRAW;wc.lpfnWndProc=WndProc;wc.cbClsExtra=0;wc.cbWndExtra=0;wc.hInstance=hInstance;wc.hIcon=LoadIcon(NULL,IDI_APPLICATION);wc.hCursor=LoadCursor(NULL,IDC_ARROW);wc.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH); //需要强制转换，原文：wc.hbrBackground=GetStockObject(WHITE_BRUSH);wc.lpszMenuName=NULL;wc.lpszClassName="SdkDemo1";// 注册窗口类RegisterClass(&wc);}// 创建应用程序主窗口hWnd=CreateWindow ("SdkDemo1", // 窗口类名"第一个Win32 SDK应用程序", // 窗口标题WS_OVERLAPPEDWINDOW, // 窗口样式CW_USEDEFAULT, // 初始化 x 坐标CW_USEDEFAULT, // 初始化 y 坐标CW_USEDEFAULT, // 初始化窗口宽度CW_USEDEFAULT, // 初始化窗口高度NULL, // 父窗口句柄NULL, // 窗口菜单句柄hInstance, // 程序实例句柄NULL); // 创建参数// 显示窗口ShowWindow(hWnd,SW_SHOW);// 更新主窗口客户区UpdateWindow(hWnd);// 开始消息循环while (GetMessage(&msg,NULL,0,0)){TranslateMessage(&msg);DispatchMessage(&msg);}return msg.wParam;}

// WndProc 主窗口过程LRESULT WINAPI WndProc (HWND hWnd,UINT msg,WPARAM wParam,LPARAM lParam){HDC hdc;RECT rc;HPEN hPen,hPenOld;HBRUSH hBrush,hBrushOld;switch (msg){case WM_PAINT:hdc=GetDC(hWnd);GetClientRect(hWnd,&rc);hPen=CreatePen(PS_SOLID,0,RGB(0,0,0));hBrush=CreateHatchBrush(HS_DIAGCROSS,RGB(0,0,0));hPenOld=(HPEN)SelectObject(hdc,hPen); //需要强制转换，原文：SelectObject(hdc,hPen);hBrushOld=(HBRUSH)SelectObject(hdc,hBrush); //需要强制转换，原文：SelectObject(hdc,hBrush);Ellipse(hdc,rc.left,rc.top,rc.right,rc.bottom);SelectObject(hdc,hPenOld);SelectObject(hdc,hBrushOld);ReleaseDC(hWnd,hdc);break;case WM_DESTROY:PostQuitMessage(0);break;default:break;}return DefWindowProc(hWnd,msg,wParam,lParam);}