protected void Page_Load(object sender, EventArgs e)
 {
     if (!IsPostBack)
     {
         Page.Title   = "Bulk Email Delete";
         H1.InnerHtml = "Bulk Email Delete";
         Master.MasterForm.Attributes.Add("enctype", "multipart/form-data");
     }
     else
     {
         _Messages = new List <string>();
         for (var i = 0; i < Request.Files.Count; i++)
         {
             var file = Request.Files[i];
             if (file.ContentLength == 0)
             {
                 continue;
             }
             try
             {
                 var address =
                     EmailUtility.ExtractUndeliverableEmailAddressFromMsg(file.InputStream);
                 if (DeleteCheckBox.Checked)
                 {
                     DoDeletions(address);
                 }
                 else
                 {
                     AnalyzeDeletions(address);
                 }
             }
             catch (Exception ex)
             {
                 _Messages.Add(
                     $"<p class=\"error\">Error processing file: {file.FileName}, {ex.Message}</p>");
             }
         }
         foreach (var address in ExtraAddresses.Text.Split(new[] { '\n' },
                                                           StringSplitOptions.RemoveEmptyEntries)
                  .Select(a => a.Trim()))
         {
             if (DeleteCheckBox.Checked)
             {
                 DoDeletions(address);
             }
             else
             {
                 AnalyzeDeletions(address);
             }
         }
         SummaryPlaceHolder.Controls.Add(new LiteralControl(string.Join(string.Empty, _Messages)));
         SummaryContainer.RemoveCssClass("hidden");
     }
 }