Message += "Selected Time range is not correct";

            if (!chkShowFTPErrorList.Checked && !chkShowHTTPErrorList.Checked)
                Message += "Either FTP or HTTP Error list must be selected.";

            if (Message != string.Empty)
            {
                MessageBox.Show(Message, "Advanced FTP Server");
                return;
            }

            lstExceptionList.Items.Clear();
            if (LogList != null) LogList.Rows.Clear();
            txtErrorDetails.Text = string.Empty;
            btnFilter.Enabled = false;
            gbSearchCondition.Visible = false;
            gbSearchInProgress.Visible = true;
            Searcher.RunWorkerAsync();
        }//点击日志过滤按钮出现筛选条件并判断
        void ClearList_Click(object sender, EventArgs e)
        {
            lstExceptionList.Items.Clear();
            txtErrorDetails.Text = string.Empty;
        }

        void Searcher_DoWork(object sender, DoWorkEventArgs e)
        {
            CancelSearch = false;
            LogList = ApplicationSettings.GetExceptionLog(txtDateFrom.Value,
                txtDateTo.Value, txtTimeFrom.Value, txtTimeTo.Value,
                chkShowFTPErrorList.Checked, chkShowHTTPErrorList.Checked, ref CancelSearch);
            gbSearchInProgress.Visible = false;
            btnFilter.Enabled = true;

            if (LogList == null || LogList.Rows.Count == 0)
            {
                gbSearchCondition.Visible = true;                
                MessageBox.Show("No results to display.", "Advanced FTP Server");
                return;
            }

            foreach (DataRow Log in LogList.Rows) C#的FTP服务器软件系统的设计与实现(13):http://www.youerw.com/jisuanji/lunwen_5865.html