clear & remove list from 2 listboxes

hey guys can u tell me i have problem in my windows form application

in my windows form there are 1 combobox , 2 listbox , 1 textbox , 2 button (one is clear & other is remove)

combobox containing service_name which are fetching from sql

listbox1 containing service_name & service_price after selecting service_name from combobox (i.e listbox1 is show in 1 row swiftcar=1000 , in 2nd row hondacity=5000)

listbox2 containing only service_price after selecting service_name from combobox (i.e listbox2 is show in 1 row 1000 , in 2nd row 5000)

textbox show addition of service_price 6000 (i.e. 1000+5000=6000)

now i want that when i am clicking on remove button it can be remove the values from both listbox1 and listbox2 when i am selecting the values from eigther listbox1 or listbox2

& reduced the service_price values from textbox also

and another solution which i want is on clear button when clicking on clear button it can be clear the all values from both listbox1 and listbox2 & textbox will show zero value

following are the my code now plz provide solution for me on remove and clear button

private void Combo_Services_Customer_SelectedIndexChanged(object sender, EventArgs e)

{

SqlConnection con = new SqlConnection("data source=ABC\\MYSQL;initial catalog=saloon;user id=abc\\Anurag;integrated security=sspi");

con.Open();

SqlCommand cmd = new SqlCommand("select Service_Price from Customer_Services where Service_Name='" + Combo_Services_Customer.SelectedItem.ToString() + "'", con);

cmd.Parameters.Add(new SqlParameter("@Customer_Services", Combo_Services_Customer.SelectedItem.ToString()));

SqlDataReader dr = cmd.ExecuteReader();

while (dr.Read())

{

listBox2.Items.Add(Convert.ToString(int.Parse(dr[0].ToString())));

listBox1.Items.Add(string.Format("{0} = {1}", Combo_Services_Customer.SelectedItem, listBox1.Text = Convert.ToString(int.Parse(dr[0].ToString()))));

decimal sum = 0;

for (int i = 0; i < listBox3.Items.Count - 0; i++)

{

sum += Convert.ToDecimal(int.Parse(listBox2.Items[i].ToString()));

}

Txt_Amt_Services_Customer.Text = Convert.ToString(sum);

}

con.Close();

}