c# 导出文本文件的函数只运行一次

如何解决c# 导出文本文件的函数只运行一次

我有一个函数可以将 gridview 的内容导出到文本文件。它工作正常，但只能工作一次。它成功导出了发送给它的第一个文件，但随后我的程序就停止了。我已经在多个 gridviews 上尝试过，所以我知道它可以工作，但它只会导出发送给它的第一个网格。我的 HTML：

<asp:Gridview runat="server" id="gvCTSWContracts" />
<asp:Gridview runat="server" id="gvCTSWDischargeCurves" />
<asp:Gridview runat="server" id="gvCTSWPrimaryDevices" />
<asp:Gridview runat="server" id="gvCTSWStations" />
<asp:Gridview runat="server" id="gvCTSWTaskOrders" />  

我的功能：

public void ExportGrid(GridView gv,string gvName)
{

    //  Build the text file data
    string txt = string.Empty;

    txt += "<table id='tblCTSWContracts' border='1'>";

    //  Add the header row for text file
    txt += "<tr>";
    foreach (TableCell cell in gv.HeaderRow.Cells)
    {
        txt += "<th>";        
        txt += cell.Text + "\t\t";
        txt += "</th>";
    }
    txt += "</tr>";

    //  Add header line
    txt += "\r\n";

    foreach (GridViewRow row in gv.Rows)
    {
        //  Add the Data rows            
        txt += "<tr>";
        foreach (TableCell cell in row.Cells)
        {
            txt += "<td>";
            txt += cell.Text + "\t\t";
            txt += "</td>";
        }
        txt += "</tr>";
        //  Add new line    
        txt += "\r\n";    
    }

    txt += "<table>";

    //  Export the file
    Response.Clear();
    Response.Buffer = true;
    Response.AddHeader("content-disposition","attachment;filename=" + gvName + ".html");
    Response.Charset = "";
    Response.ContentType = "application/text";
    Response.Output.Write(txt);
    Response.Flush();
    Response.End();

}

我是这样称呼它的：

protected void ExportAll(object sender,EventArgs e)
{
    ExportGrid(gvCTSWContracts,"CTSWContracts");
    ExportGrid(gvCTSWDischargeCurves,"CTSWDischargeCurves");
    ExportGrid(gvCTSWPrimaryDevices,"CTSWPrimaryDevices");
    ExportGrid(gvCTSWStations,"CTSWStations");
    ExportGrid(gvCTSWTaskOrders,"CTSWTaskOrders");
}

谁能告诉我为什么我的所有网格都没有作为单独的文件导出？谢谢。