submit_click
{
for(int i=0;i<=gridview.rows.count-1;i++)
{
checkbox chk=new checkbox();
chk=(checkbox)gridview.rows[i].findcontrol("chk_name");
if(chk.checked)
{
//write the code needed to get unit prices and insert into database
}
 
}
}

 protected void Button2_Click(object sender, EventArgs e)
    {
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["DatabaseConnectionString"].ToString());

        for (int i = 0; i < GridView1.Rows.Count; i++)
        {
            GridViewRow row = GridView1.Rows[i];
            CheckBox chkbox = (CheckBox)row.FindControl("chkboxSelect");
            TextBox UnitPrice = (TextBox)row.FindControl("txtUnitPrice");

            if (chkbox.Checked == true)
            {
                try
                {
                    conn.Open();

                    int Supp = Convert.ToInt16(Request.QueryString["SupplierId"]);
                    SqlCommand cmd = new SqlCommand ("INSERT INTO SuppMat (SupplierId, MaterialID, UnitPrice) VALUES (@SupplierId,'" + row.Cells[1].Text + "','" + UnitPrice.Text + "')", conn);
                    cmd.Parameters.AddWithValue("@SupplierId", Supp);
                   
                    cmd.ExecuteNonQuery();
                    conn.Close();
                }
                catch
                {
                    Response.Write("");
                }
                finally
                {
                    conn.Close();
                }
            }
           
        }
        
    }