problem regarding to the checklistbox

[GAURAV MANUSMAR]

Hey there,

I have a checkedListBox and a TextBox......Wh en I Checked item in the checkedListBox it shows the value of the respective item in the TextBox.....Whe n I Checked multiple items in the checkedListBox it shows the values of the respective items in the TextBox separating by {,}"Comma"

Now my question is that when I unchecked the item in the textBox it must remove the value of respective unchecked items from the textBox ......also plz tell me how do i remove "Comma"{,} from the end of the text box programmaticall y

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace listbox
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        

        private void Form1_Load(object sender, EventArgs e)
        {
            SqlConnection connection = new SqlConnection("Data Source=.;Initial Catalog=email_client;Integrated Security=True");
            SqlCommand command = new SqlCommand("Select * FROM address_book ", connection);

            try
            {
                connection.Open();
                {
                    SqlDataReader drd = command.ExecuteReader();

                    while (drd.Read())
                    {
                        this.checkedListBox1.Items.Add(drd.GetString(0).ToString());

                    }
                }

            }
            catch (Exception ex)
            {

                MessageBox.Show(ex.Message.ToString());

            }

            connection.Close();
        }

        private void checkedListBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
           
                SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=email_client;Integrated Security=True");
                con.Open();
                SqlCommand cmd = new SqlCommand("select * from address_book where name='" + checkedListBox1.Text + "'", con);
                SqlDataReader dr;
                dr = cmd.ExecuteReader();



                while (dr.Read())
                {
                    textBox1.Text += Convert.ToString(dr["id"] + ",");
                }


                dr.Close();
            
            
        }

        private void textBox1_Enter(object sender, EventArgs e)
        {
            ToolTip tt = new ToolTip();
            tt.SetToolTip(textBox1, "sorry");
        }

       

      
    }
}

[GAURAV MANUSMAR]

private void checkedListBox1_SelectedIndexChanged(object sender, ItemCheckEventArgs e)
{
StringBuilder stringBuilder = new StringBuilder();
 
foreach (var item in checkedListBox1.CheckedItems)
{
SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=email_client;Integrated Security=True");
con.Open();
SqlCommand cmd = new SqlCommand(string.Format("select * from address_book where name='{0}'", item), con);
SqlDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
stringBuilder.Append(Convert.ToString(dr["id"] + ","));
}
dr.Close();
}
 
textBox1.Text = stringBuilder.ToString().TrimEnd(',');
}