c# - 在 ASP 和 C# 中下载到 Excel 文件时不显示任何内容

Question

我使用下面的代码从数据表中下载 excel 文件。但是在执行它时，它正在遍历所有代码仍然没有下载文件..

private void DumpExcel(DataTable tbl)
    {
        try
        {
            string attachment = "attachment; filename=StocksHistReport.xls";
            Response.ClearContent();
            Response.AddHeader("content-disposition", attachment);
            Response.ContentType = "application/vnd.ms-excel";
            string tab = "";
            foreach (DataColumn dc in tbl.Columns)
            {
                Response.Write(tab + dc.ColumnName);
                tab = "\t";
            }
            Response.Write("\n");
            int i;
            foreach (DataRow dr in tbl.Rows)
            {
                tab = "";
                for (i = 0; i < dt.Columns.Count; i++)
                {
                    Response.Write(tab + dr[i].ToString());
                    tab = "\t";
                }
                Response.Write("\n");
            }

            //Response.BuffferOutput = True;

            HttpContext.Current.Response.Flush(); 
            HttpContext.Current.Response.SuppressContent = true;  
            HttpContext.Current.ApplicationInstance.CompleteRequest();

            //Response.Flush();
            //Response.Close();
        }
        catch (Exception ex)
        {
            lblMsg.Text = ex.Message;
            Page.ClientScript.RegisterStartupScript(GetType(), "msgbox", "alert('" + ex.Message + "');", true);
        }
    }

我在另一个示例页面中尝试了相同的代码片段，它运行良好，数据表有值..

我想问题出在网络配置文件上。作为引用，我也复制了它。

 <appSettings>
        <add key="ChartImageHandler" value="storage=file;timeout=20;deleteAfterServicing=false;privateImages=false" />
    </appSettings>
    <system.web>
        <compilation debug="true" targetFramework="4.5">
            <assemblies>
                <add assembly="System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
            </assemblies>
        </compilation>
        <httpHandlers>
            <add path="ChartImg.axd" verb="GET,HEAD,POST" type="System.Web.UI.DataVisualization.Charting.ChartHttpHandler, System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false"/>
        </httpHandlers>
        <pages>
            <controls>
                <add tagPrefix="asp" namespace="System.Web.UI.DataVisualization.Charting" assembly="System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
            </controls>
        </pages>
    </system.web>
    <system.webServer>
        <handlers>
            <remove name="ChartImageHandler" />
            <add name="ChartImageHandler" preCondition="integratedMode" verb="GET,HEAD,POST"
                path="ChartImg.axd" type="System.Web.UI.DataVisualization.Charting.ChartHttpHandler, System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
        </handlers>
        <validation validateIntegratedModeConfiguration="false" />
    </system.webServer>

可能是什么原因？如果网络配置有问题，我做错了什么？

Answer 1

这是导致所有问题的更新面板，我删除了它，现在它可以工作了。