C#

public override void EndInit()
{
    base.EndInit();
    ColumnChanging += IndustryColumnChangingEvent;
}

public void IndustryColumnChangingEvent(object sender, System.Data.DataColumnChangeEventArgs e)
{
    if (e.Column.ColumnName == "Industry")
    {
        if ((string)e.ProposedValue == "")
        {
            e.Row.SetColumnError("EIndustry_Description", "Please enter a Industry.");
        }
        else
        {
            e.Row.SetColumnError("EIndustry_Description", "");
        }
    }
}

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(uri);
            req.ClientCertificates.Add(AEXCert);
            ServicePointManager.CertificatePolicy = new CertPolicy();
            GlobalProxySelection.GetEmptyWebProxy();
            req.PreAuthenticate = false;
            req.Method = "POST";        // Post method
            req.ContentType = "text/xml";// content type
            req.KeepAlive = false;
            req.UserAgent = null;
            StreamWriter writer = new StreamWriter(req.GetRequestStream());
            TextReader reader = new StreamReader(e.FullPath);
            String XML = reader.ReadToEnd();
            reader.Close();
            writer.WriteLine(XML);
            writer.Flush();
            writer.Close();
            WebResponse rsp = req.GetResponse();//<----Error happens here----