在做一个视频监控系统的时候，运行代码时，提示“error C2451: conditional expression of type 'std::_Vector_iterator<_Ty,_Alloc>' is illegal
1>        with
1>        [
1>            _Ty=H264_DVR_FILE_DATA *,
1>            _Alloc=std::allocator<H264_DVR_FILE_DATA *>
1>        ]
1>        No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called”
这样的错误，错误指向下面源代码中的  if ( p ) 这行，请高手帮忙解决一下，本人菜鸟一名，望有高手来帮帮忙，麻烦解释得清楚些。
void CRemotePlaybackDlg::OnDestroy()
{
   
    vector<H264_DVR_FILE_DATA*>::iterator p=m_pstrFileVector.begin();
    if ( p )
    {
        H264_DVR_FILE_DATA* pData = (*p);
        delete pData;
        pData = NULL;
    }
   
    ClearResult();
    ClearMapResult();
    KillTimer(1);
    CDialog::OnDestroy();
}