其中m _ ppp 是哪个编辑框的cstring变量
以下是哪个按钮的clicked函数
```void CFileDlg::OnButton1()
{
// TODO: Add your control notification handler code here
char writeBuffer[500];
char readBuffer[500];
LONGLONG lOff = 0;
CFile file(m_ppp, CFile::modeCreate | CFile::modeReadWrite);
memset(writeBuffer, 'c', sizeof(writeBuffer));
file.Write(writeBuffer, sizeof(writeBuffer));
while (true)
{
file.Seek(lOff, CFile::begin);
int nRet = file.Read(readBuffer + lOff, 100);
lOff += nRet;
if (nRet < 100)
break;
}
file.Close();
}