服务器无法在发送 HTTP 标头之后设置内容类型

Question

如题：asp.net在导出提示“服务器无法在发送 HTTP 标头之后设置内容类型”。具体代码如下：

/// <summary>
        /// 导出方法
        /// </summary>
        /// <param name="ctr"></param>
        /// <param name="FileType">导出类型</param>
        /// <param name="FileName">导出文件名</param>
        public void GridViewToExcel(Control ctrl, string FileType, string FileName)
        {
            HttpContext.Current.Response.Charset = "GB2312";
            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.UTF8;//注意编码
            HttpContext.Current.Response.AppendHeader("Content-Disposition",
                "attachment;filename=" + HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8).ToString());
            HttpContext.Current.Response.ContentType = FileType;//image/JPEG;text/HTML;image/GIF;vnd.ms-excel/msword
            ctrl.Page.EnableViewState = false;
            StringWriter tw = new StringWriter();
            HtmlTextWriter hw = new HtmlTextWriter(tw);
            ctrl.RenderControl(hw);
            HttpContext.Current.Response.Write(tw.ToString());
            HttpContext.Current.Response.End();
        }
2、导出按钮

DateTime dt = System.DateTime.Now;
            string str = dt.ToString("药品采购入库明细MMddhhmmss");
            str = str + ".xls";
            GridViewToExcel(this.view_yprkmx, "application/ms-excel", str);
            ScriptManager.RegisterStartupScript(Page, typeof(Page), "提示", "alert('导出成功！');", true);

以上是代码，但是前台导出时提示：“服务器无法在发送 HTTP 标头之后设置内容类型”，如下图：

求大神指点!!!

Answer 1

首先你这个导出的根本不是excel而是html，只是excel也能识别html并且打开罢了。

其次你可以加上一个content-length
具体参考 https://blog.csdn.net/shi0090/article/details/44672077