c# - 在邮件中附加 excel 后检索空白 Excel

Question

我使用此代码从 gridview 发送带有 excel 附件的邮件，它对邮件部分工作正常，但 excel 附件始终为空白我已经调试了代码并确保 Gridview 的数据源传递了它需要的数据对于 gridview，似乎我没有将 gridview 渲染为 excel 正确。整个过程在 for each 循环中，具体取决于 foreach 中元素的数量..

我是否遗漏了一些代码？

protected void MailButton_Click(object sender, EventArgs e)
{
    List<FOAM> foamList = new List<FOAM>(servs.GetAreaList());
    foreach (FOAM foam in foamList)
    {
        Session["Area"] = foam.ItemAreaCode;
        Session["Principal"] = foam.PrincipalAmount;
        Session["Accountability"] = foam.AccountableAmount;
        Session["Count"] = foam.ItemCount;

        foamdetails.ItemAreaCode = foam.ItemAreaCode;
        FOAMTemplateGridview.DataSource = servs.GetFoamAsOfUnsettledforAOM(foamdetails);
        FOAMTemplateGridview.DataBind();

        StringWriter _writer = new StringWriter();
        HttpContext.Current.Server.Execute("AreaManagersMail.aspx", _writer);

        StringWriter stw = new StringWriter();
        HtmlTextWriter hw = new HtmlTextWriter(stw);
        FOAMTemplateGridview.RenderControl(hw);

        MailMessage newMail = new MailMessage();
        newMail.Priority = MailPriority.High;
        newMail.To.Add("test@test.com");
        newMail.Subject = "Unsettled FOAM As of " + DateTime.Today.ToString("MMMM dd, yyyy") + "-A" + foam.ItemAreaCode;

        System.Text.Encoding Enc = System.Text.Encoding.ASCII;
        byte[] mBArray = Enc.GetBytes(stw.ToString());
        System.IO.MemoryStream mAtt = new System.IO.MemoryStream(mBArray, false);

        newMail.Attachments.Add(new Attachment(mAtt, "test.xls"));
        newMail.Body = _writer.ToString();
        newMail.From = new MailAddress("test@test.com");
        newMail.IsBodyHtml = true;
        SmtpClient SmtpSender = new SmtpClient();
        SmtpSender.Port = 25;
        SmtpSender.Host = "MailHost";
        SmtpSender.Send(newMail);

        newMail.Dispose();
    }


}

Answer 1

您得到的是空白 excel，因为您从 stw 中获取 bytes，它已定义但从未被赋予值。

stw is only a new object with no value that's why you are getting 0 bytes array in mBArray.

比起你分配的 mAtt = new System.IO.MemoryStream(mBArray, false);。因此，mBArray 为空，mAtt 也为空，并且您从 mAtt 创建的文件为空，这就是您在电子邮件中收到空文件的原因。我想你需要改变这一行

byte[] mBArray = Enc.GetBytes(stw.ToString());

到

byte[] mBArray = Enc.GetBytes(_writer.ToString());