want to update selected row from datagridview and update in database

        private void button1_Click(object sender, EventArgs e)
        {

            string connstr = "Data Source=************";
            SqlConnection myconn = new SqlConnection(connstr);
            myconn.Open();
// here we are moving in all the rows 
            foreach (DataGridViewRow dgRow in dataGridView1.Rows)
            {
                string Id = dgRow.Cells[0].Value.ToString();
                int isEdit = Convert.ToInt32(dgRow.Cells[1].Value);
                //bool isDelete = Convert.ToBoolean(dgRow.Cells[1].Value);
                int isDelete = Convert.ToInt32(dgRow.Cells[2].Value);
                // bool  isView= Convert.ToBoolean(dgRow.Cells[4].Value);
                int isADD = Convert.ToInt32(dgRow.Cells[3].Value);
                string strQuery = "update Roles set CanEdit = '" + isEdit.ToString() + "', CanDelete='" + isDelete.ToString() + "', CanAdd='" + isADD.ToString() + "' where ID=" + Id;
                //update database with above query

                SqlCommand cmdSelect = new SqlCommand(strQuery, myconn);
                cmdSelect.ExecuteNonQuery();
            }
            myconn.Close();
        }