in my project when salesmans select from dropdownlist salemans id and its position come , select product name from dropdownlist product id and prize come sucefully. i have to show commission of that salesmans in textbox form commiion_chart table. 
 
 
plz help.   my code is below.
 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
public partial class visa_Master_customer_master : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection("Data Source=103.209.144.111;Persist Security Info=true;User ID=sparsh;Password=Visa@1234");
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            getbind();
            productbind();
            salsmanbind();
            
        }
    }
    
    private void productbind()
    {
       SqlCommand cmd= new SqlCommand("select * from itemmaster",con);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
       da.Fill(dt);
        DropDownList1.DataSource=dt;
        DropDownList1.DataValueField="id";
        DropDownList1.DataTextField="name";
        //DropDownList1.DataValueField = "price";
       DropDownList1.DataBind();
       DropDownList1.Items.Insert(0, new ListItem("------Select Product---------", "0"));
        
    }
    private void salsmanbind()
    {
        SqlCommand cmd = new SqlCommand("select * from salesmans_master", con);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        da.Fill(dt);
        DropDownList2.DataSource = dt;
        DropDownList2.DataTextField = "name";
        DropDownList2.DataValueField = "rankcode";
        DropDownList2.DataBind();
        DropDownList2.Items.Insert(0, new ListItem("------Select Salemans---------", "0"));
    }
    private void getbind()
    {
        SqlCommand cmd = new SqlCommand("Select id,Name,Addr1,Mobile from acmaster", con);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds);
        GridView1.DataSource = ds;
        GridView1.DataBind();
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        SqlCommand cmd = new SqlCommand("insert into acmaster(Name,Addr1,Mobile,Emailid,Panno,Nominee,Relation,Sponcerid,Sponcustno,Itemcode,Itemprice)values('" + customer.Text + "','" + adderss.Text + "','" + mobile.Text + "','" + emailid.Text + "','" + panno.Text + "','" + nomineen.Text + "','" + nomineer.Text + "','" + DropDownList2.SelectedItem.Value + "','" + sponcustno.Text + "','" +DropDownList1.Text+ "','" + prodid.Text + "')", con);
        cmd.CommandType = CommandType.Text;
        try
        {
            con.Open();
            cmd.ExecuteNonQuery();
            Label10.Text = "Data Inserted..";
            con.Close();
            clearfield();
        }
        catch (Exception ex)
        {
            Label10.Text = ex.Message;
        }
    }
        private void clearfield()
    {
        prodid.Text = DropDownList1.Text = sponcustno.Text  = nomineen.Text = nomineer.Text = panno.Text = emailid.Text = 
mobile.Text = adderss.Text = customer.Text = "";
    }
    
    protected void Button2_Click(object sender, EventArgs e)
    {
    }
    protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        int id = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Value.ToString());
        SqlCommand cmd = new SqlCommand("delete from acmaster where id=" + id, con);
        con.Open();
        cmd.ExecuteNonQuery();
        con.Close();
        getbind();
    }
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        
        
        prodid.Text = DropDownList1.SelectedValue.ToString();
        con.Open();
        SqlCommand cmd = new SqlCommand("select price from itemmaster where id=" + prodid.Text);
        cmd.Connection = con;
        SqlDataReader dr = cmd.ExecuteReader();
        if (dr.Read())
        {
            prodprize.Text = dr["price"].ToString();
            con.Close();
        }
        
        
    }
    protected void nomineen_TextChanged(object sender, EventArgs e)
    {
    }
    protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
    {
        
        rankid.Text = DropDownList2.SelectedValue.ToString();
        
      con.Open();
  
        SqlCommand cmd = new SqlCommand("select rank_name from rank_master where id=" + rankid.Text);
        cmd.Connection = con;
        SqlDataReader dr = cmd.ExecuteReader();
        if (dr.Read())
        {
            rankname.Text = dr["rank_name"].ToString();
            con.Close();
        }
        
    }
    //    private void getcommission()
    //{
    //    con.Open();
    //   SqlCommand cmd = new SqlCommand ("Select Commission from commission_chart where Rankid='" +rankid.Text + "' and Productid='" + prodid.Text + "'", con);
    //    cmd.Connection=con;
    //    SqlDataReader dr = cmd.ExecuteReader();
    //    if(dr.Read())
    //    {
    //        commission.Text=dr["Commission"].ToString();
    //       con.Close();
    //    }
    //}
      
    
    
    protected void commission_TextChanged(object sender, EventArgs e)
    {
        
    }
}