使用asp控件动态地向表添加行

Question

这对我有用了大约5分钟，现在我什么都没有。对象是从下拉列表中选择一个数字，然后使用该数字来指定将向表中添加的行数。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
            {
            }

        protected void Button1_Click(object sender, EventArgs e)
            {
                //variables for the number of rows and cells
                int numrows = int.Parse(DropDownList1.SelectedValue);
                int numcells = 3;
                for (int j = 0; j < numrows; j++)
                    {
                        HtmlTableRow r = new HtmlTableRow();
                        r.BgColor = "Gainsboro";
                        //demoTable.Rows.Add(r);

                        for (int i = 0; i < numcells; i++)
                            {
                                HtmlTableCell c = new HtmlTableCell();
                                c.InnerHtml = " row " + j.ToString() + ", cell " + i.ToString();
                                r.Cells.Add(c);    
                            }
                        demoTable.Rows.Add(r);
                    }
            }
    }