How To Edit the Row In Data Grid View

protected void GalleryView_RowCommand(object sender, GridViewCommandEventArgs e)
    {
        if (e.CommandName == "Select")
        {
            int id = Convert.ToInt32(e.CommandArgument);
            Session["Sno"] = id.ToString();
            SqlCommand cmd = new SqlCommand("Select TitleService from RW_Gallerys where Sno='" + id.ToString() + "'", con);
            con.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            if (dr.Read() == true)
            {
                Session["TitleService"] = dr[0].ToString();
            }
            dr.Close();
            SqlDataAdapter da = new SqlDataAdapter("select ImageServices from RW_GallerysImage where Sno='" + id.ToString() + "'", con);

            DataSet ds = new DataSet();
            da.Fill(ds, "RW_Gallerys");
            GalleryList.DataSource = ds.Tables[0];
            GalleryList.DataBind();
            panel1.Visible = false;
            panel2.Visible = true;
            AddImages.Visible = true;

        }
    }