dt：DataTable

strFile：fileName

strExt：type

private void GridExport(DataTable dt, string strFile, string strExt)

    {

        string strAppType = "";

        switch (strExt)

        {

            case "xls":

                strAppType = "application/ms-excel";

                break;

            case "doc":

                strAppType = "application/ms-word";

                break;

            case "txt":

                strAppType = "application/ms-txt";

                break;

            case "html":

            case "htm":

                strAppType = "application/ms-html";

                break;

            default: return;

        }

        GridView MyGridView = new GridView();

        MyGridView.DataSource = dt;

        MyGridView.DataBind(); 

        HttpContext.Current.Response.Clear();

        HttpContext.Current.Response.Buffer = true;

        HttpContext.Current.Response.AddHeader("Content-Type", "text/html; charset=GB2312");

        HttpContext.Current.Response.AppendHeader("Content-Disposition", string.Format("attachment;filename={0}.{1}", HttpUtility.UrlEncode(strFile,Encoding.GetEncoding("GB2312")), strExt));

        HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312"); 

        HttpContext.Current.Response.ContentType = strAppType; 

        //MyGridView.Page.EnableViewState = false;

        //二、定义一个输入流

        System.Globalization.CultureInfo myCItrad = new System.Globalization.CultureInfo("ZH-CN", true);

        System.IO.StringWriter oStringWriter = new System.IO.StringWriter(myCItrad);

        System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);

        //三、将目标数据绑定到输入流输出

        MyGridView.RenderControl(oHtmlTextWriter);

        HttpContext.Current.Response.Write(oStringWriter.ToString());

        HttpContext.Current.Response.End();

    }