ต้องการสร้าง textbox, dropdownlist ใน table cell คอลัมน์ที่ต้องการ โดยรับค่าจำนวนตามที่ใส่

using System;
using System.Collections;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

namespace WebApplication1
{
    public partial class _Default : System.Web.UI.Page
    {
        List<TextBox> ArrayTextBox;

        protected void Page_Load(object sender, EventArgs e)
        {
        }
           protected void Button1_Click(object sender, EventArgs e)
	        {
               
               CreateTextBox();

               int nrows;
               int ncells;
               //int numrows;
               //int numcells;
               int i = 0;
               int j = 0;
               TableRow r;
               TableCell c;

               // Generate rows and cells
               nrows = Convert.ToInt32(this.txtRow.Text);
               ncells = Convert.ToInt32(this.txtCell.Text);
               //numrows = Convert.ToInt32(DropDown1.SelectedItem.Value);
               //numcells = Convert.ToInt32(DropDown2.SelectedItem.Value);

               for (j = 0; j <= nrows - 1; j++)
               {

                   r = new TableRow();

                   for (i = 0; i <= ncells - 1; i++)
                   {
                       c = new TableCell();
                       TextBox aTextBox = new TextBox();
                       //aTextBox.ID = "aTextBox" + i.ToString();
                       //c.Controls.Add(aTextBox);
                       //c.Controls.Add(new LiteralControl("row " + j + ", cell " + i));
                       c.Controls.Add(aTextBox);
                       r.Cells.Add(c);
                   }

                   Table1.Rows.Add(r);
               }

           } //ปิด class Button1_Click
          
               protected  void CreateTextBox()
                {
                     if (txtNumText.Text != ""){
                int count = int.Parse(txtNumText.Text);

                if (count > 0){
                    ArrayTextBox = new List<TextBox>();

                    for (int i = 0; i < count; i++)
                    {
                        TextBox aTextBox = new TextBox();
                        aTextBox.ID = "aTextBox" + i.ToString();
                        ArrayTextBox.Add(aTextBox);

                        RequiredFieldValidator aRequiredFieldValidator = new RequiredFieldValidator();
                        aRequiredFieldValidator.ControlToValidate = "aTextBox" + i.ToString();
                        aRequiredFieldValidator.ErrorMessage = "*";

                        PlaceHolder1.Controls.Add(aTextBox);
                        //PlaceHolder1.Controls.Add(aRequiredFieldValidator);
                        PlaceHolder1.Controls.Add(new LiteralControl(@"<br />"));
                    }

                    //Button ButtonShow = new Button();
                    //ButtonShow.Text = "Show";
                    //ButtonShow.Click += new EventHandler(ButtonShow_Click);

                    //PlaceHolder1.Controls.Add(ButtonShow);
                    //TextBox1.ReadOnly = true;
                    //Button1.Enabled = false;
                } //ปิด if Count
            } //ปิด if txtNumText
        } // ปิด class CreateTextBox
   

      
    } //ปิด public class _Default
} //ปิด namespace