How to Bind Two dropdown List from Asp.Net Table

<div class="field"><asp:Table ID="tblquotation" runat="server" CssClass="mGrid">
                               </asp:Table></div>

int count = Convert.ToInt32(ViewState["Product"].ToString());
                for (int i = 0; i <= count; i++)
                {
                    if (i == 0)
                    {
                        TableHeaderRow tr = new TableHeaderRow();
                        //TableRow tr = new TableRow();

                        TableHeaderCell tc1 = new TableHeaderCell();
                        tc1.Text = "S.No.";
                        tr.Cells.Add(tc1);



                        TableHeaderCell tc2 = new TableHeaderCell();

                        tc2.Text = "GroupName";
                        tr.Cells.Add(tc2);



                        TableHeaderCell tc3 = new TableHeaderCell();
                        tc3.Text = "Name";
                        tr.Cells.Add(tc3);
                        tblquotation.Controls.Add(tr);
                      }
                    else
                    {
                           TableRow tr = new TableRow();

                        TableCell tc1 = new TableCell();
                        tc1.Text = i.ToString();
                        tc1.HorizontalAlign = HorizontalAlign.Center;
                        tr.Cells.Add(tc1);


                        TableCell tc2 = new TableCell();
                        //TextBox txtbasic = new TextBox();
                        DropDownList txtbasic = new DropDownList();
                        SqlDataReader dr =   commonfunctions.ExecuteQueryReturnDataReader("sp_Group_Purchase");
                        if (dr.HasRows)
                        {
                            txtbasic.DataTextField = "GroupName";
                            txtbasic.DataValueField = "GId";
                            txtbasic.DataSource = dr;
                            txtbasic.DataBind();
                        }
                        txtbasic.Items.Insert(0, "<--Select-->");

                        txtbasic.ID = "txtbasic" + i.ToString();
                        txtbasic.AutoPostBack = true;
                        txtbasic.SelectedIndexChanged += txtbasic_SelectedIndexChanged;
                         
                        tc2.Controls.Add(txtbasic);
                        tc2.HorizontalAlign = HorizontalAlign.Center;
                        tr.Cells.Add(tc2);



                        TableCell tc3 = new TableCell();
                        //TextBox txtbasic = new TextBox();
                        DropDownList ddlName = new DropDownList();
                        SqlDataReader dr4 =  commonfunctions.ExecuteQueryReturnDataReader("sp_Itemname_Purchase");
                        if (dr4.HasRows)
                        {
                            ddlName.DataTextField = "ItemName";
                            ddlName.DataValueField = "ItemId";
                            ddlName.DataSource = dr4;
                            ddlName.DataBind();
                        }
                        ddlName.Items.Insert(0, "<--Select-->");

                        ddlName.ID = "ddlName" + i.ToString();

                       // txtbasic.Attributes.Add("onkeypress", "return isNumberKey(event);");
                        tc3.Controls.Add(ddlName);
                        tc3.HorizontalAlign = HorizontalAlign.Center;
                        tr.Cells.Add(tc3); 
                        tblquotation.Controls.Add(tr);
                       }      
}          
}