VC++文件操作

 try
	{
		CString strText;
		strText.Format("%d,%s%s", iFacIndex, strTime, strValue);
		if (GetFileAttributes("data.txt") == INVALID_FILE_ATTRIBUTES)
		{
			HANDLE hOpenFile = CreateFileA(_T("data.txt"),GENERIC_WRITE,
                                FILE_SHARE_READ|FILE_SHARE_WRITE,
				NULL,CREATE_ALWAYS/*|OPEN_EXISTING*/,FILE_ATTRIBUTE_NORMAL,NULL);
			if (hOpenFile != INVALID_HANDLE_VALUE)
			{
				DWORD dwBytesWritten;
				WriteFile(hOpenFile, strText.GetBuffer(), strText.GetLength(), 
                                          &dwBytesWritten, NULL);
				CloseHandle((void *)hOpenFile);
			}
		}
		else
		{
			CFile file;
			if (file.Open("data.txt",CFile::modeCreate|CFile::shareDenyNone|CFile::modeWrite
                                      /*|CFile::typeText*/))
			{
				file.Write(strText.GetBuffer(), strText.GetLength());
				file.Close();
			}
		}
	}
	catch (CMemoryException* e)
	{
		TCHAR szBuff[MAX_PATH+1]={0};
		e->GetErrorMessage(szBuff, MAX_PATH);
		AfxMessageBox(szBuff);
	}
	catch (CFileException* e)
	{
		TCHAR szBuff[MAX_PATH+1]={0};
		e->GetErrorMessage(szBuff, MAX_PATH);
		AfxMessageBox(szBuff);
	}
	catch (CException* e)
	{
		TCHAR szBuff[MAX_PATH+1]={0};
		e->GetErrorMessage(szBuff, MAX_PATH);
		AfxMessageBox(szBuff);
	}

说明：

1.如果文件不存在，CreateFile指定OPEN_EXISTING标志将导致调用失败；

2.CFile不支持文本格式打开，只能在继承类中使用，Open中指定typeText标志将导致程序崩溃；

3.代码中判断文件是否存在功能有重复，只是为了展示文件用法需要。