RenderControl的Excel导出后看不懂

[dgxsz]

先看代码：
Response.Clear();
Response.Buffer = true;
Response.Charset = "GB2312";
Response.AppendHeader("Content-Disposition", "attachment;filename=ExcelName.xls");
Response.ContentEncoding = System.Text.Encoding.UTF7;
Response.ContentType = "application/ms-excel"; //设置输出文件类型为excel文件。
System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
this.EnableViewState = false;

TextBox1.RenderControl(oHtmlTextWriter);
Response.Output.Write(oStringWriter.ToString());

Response.Flush();
Response.End();

这是我第一次做Excel导出。我在TextBox1中输入as9527后，打开导出的Excel后内容为"+ADw-input name+AD0AIg-ctl00+ACQ-ContentPlaceHolder1+ACQ-TextBox1+ACI- type+AD0AIg-text+ACI- value+AD0AIg-as9527+ACI- id+AD0AIg-ctl00+AF8-ContentPlaceHolder1+AF8-TextBox1+ACI- /+AD4-"
我之前用GridView.RenderControl方法，明明里面是一张表，但打开后是类似以上的两行乱码，请教是怎么回事，是不是我在哪一块疏忽了。

[whoami333]

protected void btnImpExecl_Click(object sender, EventArgs e)
{
Response.ClearContent();
Response.AddHeader("content-disposition", "attachment; filename=ExcelName.xls");
Response.ContentType = "application/excel";
StringWriter sw = new StringWriter();
HtmlTextWriter htw = new HtmlTextWriter(sw);
GridView1.RenderControl(htw);
Response.Write(sw.ToString());
Response.End();
}

[LQknife]

晓习 帮顶

[dgxsz]

一楼哥们的这段，就是我源代码的基础，我就是根据这个改的，行不能啊。