将 html 表另存为 excel 时会出现错误

TableRow tr = new TableRow();
TableCell yrs = new TableCell();
yrs.BorderWidth = 1;
yrs.BorderColor = System.Drawing.Color.Black;
yrs.Text = year.Substring(4);
tr.Cells.Add(yrs);
TableCell fname = new TableCell();
fname.BorderWidth = 1;
fname.BorderColor = System.Drawing.Color.Black;
fname.Text = test;
tr.Cells.Add(fname);
TableCell lname = new TableCell();
lname.BorderWidth = 1;
lname.BorderColor = System.Drawing.Color.Black;
lname.Text = test1.ToString();
tr.Cells.Add(lname);
TABULAR.Rows.Add(tr);
Response.Write(TABULAR);
Response.Clear();
Response.AddHeader("content-disposition", "attachment;filename=test123.xls");
Response.Charset = "";
Response.ContentType = "application/vnd.ms-excel";
StringWriter swWriter = new StringWriter();
HtmlTextWriter htwWriter = new HtmlTextWriter(swWriter);
TABULAR.RenderControl(htwWriter);
Response.Write(swWriter.ToString());
Response.End();