C# 尝试使用gridview的linkbutton从数据库下载文件时出错

我试图使用gridview的linkbutton从数据库下载一个文件，但没有发生任何事情，因为它给了我一个错误，也没有下载该文件。 以下是我的实体：

我的数据库中有3个库号-SaleID和salefilename此库号存储文件及其名称，salename此列以字节存储相同的文件

以下是by.aspx代码：

<asp:TemplateField HeaderText="SaleName" SortExpression="SaleName">
                                <ItemTemplate>
                                    <asp:LinkButton ID="LinkButton1" runat="server" CommandArgument='<%# Bind("SaleFileName") %>' Text='<%# Bind("SaleName") %>' ></asp:LinkButton>
                                </ItemTemplate>
                            </asp:TemplateField>

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当我们点击链接按钮下载文件时，网页没有给我任何回应，我是C语言的新手，任何人都可以告诉我哪里出错，这将是一个很大的帮助

是e.CommandName下载还是'SaleName？CommanName已下载，但您显示的链接按钮未下载，是吗？是的CommandName已下载。是否使用UpdatePanel！？

 protected void gridContributions_RowCommand(object sender, GridViewCommandEventArgs e)
    {
        if (e.CommandName == "Download")
        {
      // make sure fileName  contains only file name like 'test.pdf'  
            string fileName = Convert.ToString(e.CommandArgument);

            // make sure filePath  contains file path like 'Uploads/Scheme/test.pdf' 

             string filePath = e.CommandArgument.ToString();


            string connectionString = WebConfigurationManager.ConnectionStrings["ConnectionString2"].ConnectionString;
            // SqlConnection con = new SqlConnection(connectionString);

            byte[] bytes;
            //string ContentType;

            using (SqlConnection con = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    cmd.CommandText = "select SaleFileName from Sales";
                    cmd.Parameters.AddWithValue("@SaleFileName", SaleFileName );
                    cmd.Connection = con;
                    con.Open();
                    using (SqlDataReader sdr = cmd.ExecuteReader())
                    {
                        sdr.Read();
                        bytes = (byte[])sdr["SaleFileName"];

                    }
                    con.Close();
                }
            }
            Response.Clear();
            Response.Buffer = true;

            // Read the original file from disk
             FileStream myFileStream = new FileStream( filePath  ,FileMode.Open);
            long FileSize = myFileStream.Length;
            byte[] Buffer = new byte[Convert.ToInt32(FileSize)];
            myFileStream.Read(Buffer, 0, Convert.ToInt32(FileSize));
            myFileStream.Close();




           // // Tell the browse stuff about the file
            Response.AddHeader("Content-Length", bytes.ToString());
            //Response.AddHeader("Content-Disposition", "inline; filename=" & fileName.Replace(" ", "_"));
            Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName + ";");
            Response.TransmitFile(fileName);
            Response.ContentType = "application/octet-stream";

            // Send the data to the browser
            Response.BinaryWrite(Buffer);
            Response.End();
        }
    }