with this code am trying to update my table .but am not getting idea how to execute it.

public void ServiceInfo(int id)
       {

           string conn = Connection.ConnectionString;
           //"Data Source=IN-WKS-410;Initial Catalog=MSNETDB;Integrated Security=True;Pooling=False";
           SqlConnection mycon = new SqlConnection(conn);
           mycon.Open();
           foreach (DataGridViewRow row in dataGridView1.Rows)
           {

               string DisplayName = row.Cells[3].Value.ToString();
               string ServiceName = row.Cells[4].Value.ToString();
               string Status = row.Cells[5].Value.ToString();
               string ServiceType = row.Cells[6].Value.ToString();
               int UserId;
               SqlCommand com = new SqlCommand(conn, mycon);
               //Insert System table ID
               if (UpdateServices(UserId))
               {
                   com.CommandText = "insert into ServiceInfo(DisplayName,ServiceName,Status,ServiceType,UserId)values('" + DisplayName + "','" + ServiceName + "','" + Status + "','" + ServiceType + "'," + id + ")";
               }
               else
               {
                   com.CommandText = "UPDATE ServiceInfo SET" + " DisplayName='" + DisplayName + "',ServiceName='" + ServiceName + "',Status='" + ServiceType + "',ServiceType='" + ServiceType + "',UserId='"+UserId +"' Where UserId='" + UserId  + "'";
               }
               com.ExecuteNonQuery();
               com.Parameters.Clear();
               com.Dispose();


           }

           mycon.Close();
           mycon.Dispose();

       }