一下是我写的代码：

    protected string t()
    {
        IList<Biaodan> list = BiaodanManager.GetAll();
        StringBuilder strlist = new StringBuilder();
        strlist.Append("<table><tr><td>姓名：<input ID=\"TextBox1\" runat=\"server\"></asp:TextBox></td></tr><tr><td>姓名：<input ID=\"TextBox1\" runat=\"server\"></asp:TextBox></td></tr>");
        foreach (Biaodan b in list)
        {
            if (b.FTypeName == "文本录入")
            {
                //DropDownList d = new DropDownList();
                //ListItem item = new ListItem();
                //item.Text = "a";
                //item.Value = "a";
                //d.Items.Add(item);
                TextBox t = new TextBox();
                t.ID = b.JId.ToString();
                //Page.FindControl("asda").Controls.Add(t);
                strlist.AppendLine("<tr>单位：<span ID=\"s" + b.JId + "\" ></span>  </td></tr>");
                string f = "s" + b.JId.ToString();
                Page.FindControl("form1").FindControl(f).Controls.Add(t);
            }

        }
        strlist.Append("</table>");
        return strlist.ToString();
    }