为窗体加上滚动条

为windows32窗体加入滚动条，代码如下：

#include<windows.h>LRESULT CALLBACK WindowProc(  HWND hwnd,      // handle to window  UINT uMsg,      // message identifier  WPARAM wParam,  // first message parameter  LPARAM lParam   // second message parameter);int WINAPI WinMain(  HINSTANCE hInstance,      // handle to current instance  HINSTANCE hPrevInstance,  // handle to previous instance  LPSTR lpCmdLine,          // command line  int nCmdShow              // show state  ){static TCHAR szAppName[]=TEXT("AppName");HWND hwnd;MSG msg;WNDCLASS wndclass;wndclass.cbClsExtra=0;wndclass.cbWndExtra=0;wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);wndclass.hCursor=LoadCursor(NULL,IDC_ARROW);wndclass.hIcon=LoadIcon(NULL,IDI_APPLICATION);wndclass.hInstance=hInstance;wndclass.lpfnWndProc=WindowProc;wndclass.lpszClassName=szAppName;wndclass.lpszMenuName=NULL;wndclass.style=CS_HREDRAW|CS_VREDRAW;if(!RegisterClass(&wndclass)){MessageBox(NULL,TEXT("This program requires Windows NT"),szAppName,MB_ICONERROR);}hwnd=CreateWindow(  szAppName,  // registered class name  TEXT("This is title"), // window name  WS_OVERLAPPEDWINDOW|WS_VSCROLL,        // window style  CW_USEDEFAULT,                // horizontal position of window  CW_USEDEFAULT,                // vertical position of window  CW_USEDEFAULT,           // window width  CW_USEDEFAULT,          // window height  NULL,      // handle to parent or owner window  NULL,          // menu handle or child identifier  hInstance,  // handle to application instance  NULL        // window-creation data);ShowWindow(hwnd,nCmdShow);UpdateWindow(hwnd);while(GetMessage(&msg,NULL,0,0)){TranslateMessage(&msg);DispatchMessage(&msg);}return msg.wParam;}LRESULT CALLBACK WindowProc(  HWND hwnd,      // handle to window  UINT uMsg,      // message identifier  WPARAM wParam,  // first message parameter  LPARAM lParam   // second message parameter){static int cxClient,cyClient,cxChar,cyChar,iVscrollPos;HDC hdc;PAINTSTRUCT ps;int i=50,j=20;TCHAR szBuffer[20];TEXTMETRIC tm;int numberline=30;switch(uMsg){case WM_CREATE://hdc=GetDC(hwnd);//TextOut(hdc,0,0,TEXT("hello,world"),strlen("hello,world"));//ReleaseDC(hwnd,hdc);hdc=BeginPaint(hwnd,&ps);GetTextMetrics(hdc,&tm);SetScrollRange(hwnd,SB_VERT,0,numberline-1,FALSE);SetScrollPos(hwnd,SB_VERT,iVscrollPos,TRUE);cyChar=(tm.tmHeight+tm.tmExternalLeading);EndPaint(hwnd,&ps);return 0;case WM_PAINT:hdc=BeginPaint(hwnd,&ps);GetTextMetrics(hdc,&tm);TextOut(hdc,iVscrollPos,iVscrollPos,szBuffer,wsprintf(szBuffer,TEXT("%d"),tm.tmAveCharWidth));//字符宽度TextOut(hdc,iVscrollPos+30,iVscrollPos+40,szBuffer,wsprintf(szBuffer,TEXT("%d"),tm.tmHeight+tm.tmExternalLeading));//字符长度EndPaint(hwnd,&ps);return 0;case WM_VSCROLL:switch(LOWORD(wParam)){case SB_LINEUP:iVscrollPos-=100;//为了效果更明显由iVscrollPos-=1;改成了iVscrollPos-=100;break;case SB_LINEDOWN:iVscrollPos+=100;break;case SB_PAGEUP:iVscrollPos-=cyClient/cyChar;//cyClient/cyChar表示一页最多几行或一列最多包括多少个字符break;case SB_PAGEDOWN:iVscrollPos+=cyClient/cyChar;break;case SB_THUMBPOSITION:iVscrollPos=HIWORD(wParam);break;default:break;}iVscrollPos=max(0,min(iVscrollPos,numberline-1));if(iVscrollPos!=GetScrollPos(hwnd,SB_VERT)){SetScrollPos(hwnd,SB_VERT,iVscrollPos,TRUE);InvalidateRect(hwnd,NULL,TRUE);}return 0;case WM_SIZE:cyClient=HIWORD(lParam);return 0;/*case WM_SIZE:hdc=BeginPaint(hwnd,&ps);cxClient=LOWORD(lParam);cyClient=HIWORD(lParam);GetTextMetrics(hdc,&tm);TextOut(hdc,0,100,szBuffer,wsprintf(szBuffer,TEXT("%d"),cxClient/tm.tmAveCharWidth));//一行最多显示多少个字符TextOut(hdc,0,150,szBuffer,wsprintf(szBuffer,TEXT("%d"),cyClient/(tm.tmHeight+tm.tmExternalLeading)));//一列最多显示多少字符EndPaint(hwnd,&ps);return 0;*/case WM_DESTROY:PostQuitMessage(0);return 0;}return DefWindowProc(hwnd,uMsg,wParam,lParam);}

截图如下：