C# 在邮件中附加Excel时检索空白Excel

我用这段代码从gridview发送一封带有excel附件的邮件，邮件部分效果很好，但excel附件始终为空。我已经调试了代码，并确保gridview的数据源将所需的数据传递给gridview，似乎我没有正确地将gridview呈现给excel。整个过程是一个for-each循环，具体取决于foreach中元素的数量

我丢失了一些代码吗

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();
    }


}

受保护的无效邮件按钮\u单击（对象发送者，事件参数e）
{
List foamList=新列表（servs.GetAreaList（））；
foreach（泡沫列表中的泡沫）
{
会话[“区域”]=foam.ItemAreaCode；
会话[“委托人”]=foam.PrincipalAmount；
会话[“责任”]=应收账款金额；
会话[“计数”]=foam.ItemCount；
foamdetails.ItemAreaCode=foam.ItemAreaCode；
FOAMTemplateGridview.DataSource=servs.getFoamAsofunSettledForOM（foamdetails）；
FOAMTemplateGridview.DataBind（）；
StringWriter _writer=新建StringWriter（）；
HttpContext.Current.Server.Execute（“AreaManagerMail.aspx”，U writer）；
StringWriter stw=新StringWriter（）；
HtmlTextWriter hw=新的HtmlTextWriter（stw）；
FOAMTemplateGridview.RenderControl（hw）；
MailMessage newMail=newmailmessage（）；
newMail.Priority=MailPriority.High；
newMail.To.Add（“test@test.com");
newMail.Subject=“截至”+DateTime.Today.ToString（“MMMM dd，yyyy”）+“-A”+FOAM.ItemAreaCode；
System.Text.Encoding Enc=System.Text.Encoding.ASCII；
字节[]mBArray=Enc.GetBytes（stw.ToString（））；
System.IO.MemoryStream mAtt=新的System.IO.MemoryStream（mBArray，false）；
添加（新附件（mAtt，“test.xls”）；
newMail.Body=_writer.ToString（）；
newMail.From=新邮件地址（“test@test.com");
newMail.IsBodyHtml=true；
SmtpClient SmtpSender=新的SmtpClient（）；
SmtpSender.Port=25；
SmtpSender.Host=“MailHost”；
SmtpSender.Send（newMail）；
Dispose（）；
}
}

您将获得空白excel，因为您将从

stw

中获得

字节

，该字节已定义，但从未给定值

stw

只是一个没有值的新对象，这就是为什么您会得到

0
字节数组

位于

mBArray

中

然后分配

mAtt=new System.IO.MemoryStream（mBArray，false）。因此，由于
mBArray
是空的，所以
mAtt
也是空的，并且您已经从
mAtt
创建了文件，该文件是空的，这就是您在电子邮件中收到空文件的原因。我想你需要换一条线

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

到

我自己找到了答案

不是直接渲染gridview，而是在表中传递gridview的值，然后该表就是我用于渲染的表

样本如下：

    Table table = new Table();     
    table.Rows.AddAt(3, FOAMTemplateGridview.HeaderRow);

                foreach (GridViewRow row in FOAMTemplateGridview.Rows)
                {
                    int index = 0;
                    table.Rows.Add(row);
                    foreach (TableCell tc in row.Cells)
                    {
                        switch (index)
                        {

                            case 0: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 1: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 2: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 3: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 4: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 5: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 6: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 7: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 8: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 9: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 10: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 11: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 12: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 13: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 14: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 15: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 16: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                        }
                        tc.Attributes.Add("class", "text");
                        tc.BorderStyle = System.Web.UI.WebControls.BorderStyle.Solid;
                        tc.BorderColor = Color.Black;
                        tc.Font.Name = "Arial";
                        tc.Font.Size = 10;
                        index++;
                    }

                }
            StringWriter stw = new StringWriter();
            HtmlTextWriter hw = new HtmlTextWriter(stw);
            hw.WriteLine(@"<style>.text { mso-number-format:\@; } </style>");
            table.RenderControl(hw);

            MailMessage newMail = new MailMessage();
            newMail.Priority = MailPriority.High;
            newMail.To.Add(foam.AomMail);
            newMail.Subject = "Subject";
            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, "sales.xls"));  

Table Table=新表（）；
table.Rows.AddAt（3，FOAMTemplateGridview.HeaderRow）；
foreach（FOAMTemplateGridview.Rows中的GridViewRow行）
{
int指数=0；
table.Rows.Add（行）；
foreach（第行单元格中的表格单元格tc）
{
开关（索引）
{
案例0:tc.HorizontalAlign=HorizontalAlign.Left；
打破
案例1:tc.HorizontalAlign=HorizontalAlign.Right；
打破
案例2:tc.HorizontalAlign=HorizontalAlign.Right；
打破
案例3:tc.HorizontalAlign=HorizontalAlign.Left；
打破
案例4:tc.HorizontalAlign=HorizontalAlign.Right；
打破
案例5:tc.HorizontalAlign=HorizontalAlign.Left；
打破
案例6:tc.HorizontalAlign=HorizontalAlign.Left；
打破
案例7:tc.HorizontalAlign=HorizontalAlign.Right；
打破
案例8:tc.HorizontalAlign=HorizontalAlign.Left；
打破
案例9:tc.HorizontalAlign=HorizontalAlign.Right；
打破
案例10:tc.HorizontalAlign=HorizontalAlign.Right；
打破
案例11:tc.HorizontalAlign=HorizontalAlign.Right；
打破
案例12:tc.HorizontalAlign=HorizontalAlign.Right；
打破
案例13:tc.HorizontalAlign=HorizontalAlign.Right；
打破
案例14:tc.HorizontalAlign=HorizontalAlign.Left；
打破
案例15:tc.horizontallign=horizontallign.Left；
打破
案例16:tc.HorizontalAlign=HorizontalAlign.Left；
打破
}
添加（“类”、“文本”）；
tc.BorderStyle=System.Web.UI.WebControls.BorderStyle.Solid；
tc.BorderColor=颜色.黑色；
tc.Font.Name=“Arial”；
tc.Font.Size=10；
索引++；
}
}
StringWriter stw=新StringWriter（）；
HtmlTextWriter hw=新的HtmlTextWriter（stw）；
hw.WriteLine（@）.text{mso编号格式：\@；}”）；
    Table table = new Table();     
    table.Rows.AddAt(3, FOAMTemplateGridview.HeaderRow);

                foreach (GridViewRow row in FOAMTemplateGridview.Rows)
                {
                    int index = 0;
                    table.Rows.Add(row);
                    foreach (TableCell tc in row.Cells)
                    {
                        switch (index)
                        {

                            case 0: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 1: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 2: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 3: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 4: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 5: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 6: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 7: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 8: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 9: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 10: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 11: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 12: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 13: tc.HorizontalAlign = HorizontalAlign.Right;
                                break;
                            case 14: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 15: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                            case 16: tc.HorizontalAlign = HorizontalAlign.Left;
                                break;
                        }
                        tc.Attributes.Add("class", "text");
                        tc.BorderStyle = System.Web.UI.WebControls.BorderStyle.Solid;
                        tc.BorderColor = Color.Black;
                        tc.Font.Name = "Arial";
                        tc.Font.Size = 10;
                        index++;
                    }

                }
            StringWriter stw = new StringWriter();
            HtmlTextWriter hw = new HtmlTextWriter(stw);
            hw.WriteLine(@"<style>.text { mso-number-format:\@; } </style>");
            table.RenderControl(hw);

            MailMessage newMail = new MailMessage();
            newMail.Priority = MailPriority.High;
            newMail.To.Add(foam.AomMail);
            newMail.Subject = "Subject";
            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, "sales.xls"));