你应该调用 PrintWindow API:
void CScreenShotDlg::OnPaint()
{
// device context for painting
CPaintDC dc(this);
// Get the window handle of calculator application.
HWND hWnd = ::FindWindow( 0, _T( "Calculator" ));
// Take screenshot.
PrintWindow( hWnd,
dc.GetSafeHdc(),
0 );
}
看到这个问题:获取窗口截图 Windows API
如果您不使用 MFC,这里是纯 PrintWindow 签名:
BOOL PrintWindow(
HWND hwnd,
HDC hdcBlt,
UINT nFlags
);
请参阅 MSDN 了解更多详细信息:http://msdn.microsoft.com/en-us/library/dd162869(v=vs.85).aspx
关于如何将其保存为位图,如 Matteo 所说,取决于您使用的实际框架......
EDIT:
这里是原始 C++ 的完整示例
#define _WIN32_WINNT 0x0501 //xp
#include <windows.h>
int main()
{
RECT rc;
HWND hwnd = FindWindow(TEXT("Notepad"), NULL); //the window can't be min
if (hwnd == NULL)
{
cout << "it can't find any 'note' window" << endl;
return 0;
}
GetClientRect(hwnd, &rc);
//create
HDC hdcScreen = GetDC(NULL);
HDC hdc = CreateCompatibleDC(hdcScreen);
HBITMAP hbmp = CreateCompatibleBitmap(hdcScreen,
rc.right - rc.left, rc.bottom - rc.top);
SelectObject(hdc, hbmp);
//Print to memory hdc
PrintWindow(hwnd, hdc, PW_CLIENTONLY);
//copy to clipboard
OpenClipboard(NULL);
EmptyClipboard();
SetClipboardData(CF_BITMAP, hbmp);
CloseClipboard();
//release
DeleteDC(hdc);
DeleteObject(hbmp);
ReleaseDC(NULL, hdcScreen);
cout << "success copy to clipboard, please paste it to the 'mspaint'" << endl;
return 0;
}