dataGrid row

Hi, I have a datagrid that is bind to a DataTable. I add values in datagrid cells and save-delete-update rows.

If I add a new value in  one cell only of datagrid row, I want, after the msg, the user to be able to add the empty cell and save.

if the user adds the missing value after msg an error appears: Syntax error (missing operator) in query expression 'id='

XAML:

<DataGrid x:Name="dGService" AutoGenerateColumns="False" ItemsSource="{Binding}"RowEditEnding="rowEditEnding"><DataGrid.Columns><DataGridTextColumn Header="vehicle" Binding="{Binding vehicle, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/><DataGridTextColumn Header="dateService" EditingElementStyle="{StaticResource errorStyle}" Binding="{Binding Path=dateService, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/></DataGrid.Columns></DataGrid>

C#:

 private void rowEditEnding(object sender, DataGridRowEditEndingEventArgs e)
        {
            // connection
            OleDbCommand cmd = new OleDbCommand();
            if (con.State != ConnectionState.Open)
                con.Open();
            cmd.Connection = con;

            DataRowView row = (DataRowView)dGService.SelectedItems[0];

            // if row is selected
            if (dGService.SelectedItems.Count > 0)
            {
                // if one of the cells is empty
                if (string.IsNullOrWhiteSpace(row["vehicle"].ToString()) || string.IsNullOrWhiteSpace(row["dateService"].ToString()))//----if one cell is empty
                {
                  MessageBox.Show("ADD MISSING VALUE...")
                }
                else
                {
                    // if row is new
                    if (row.IsNew)
                    {
                        // save
                        try
                        {
                            cmd.CommandText = "insert into service(vehicle,dateService) Values('" + row["vehicle"] + "','" + row["dateService"] + "')";
                            cmd.ExecuteNonQuery();
                        }
                        catch (Exception ex)
                        {
                            MessageBox.Show(": " + ex.Message, "Επισήμανση", MessageBoxButton.OK, MessageBoxImage.Warning);
                        }
                        finally
                        {
                            con.Close();
                        }
                    }
                    // if row is not new update
                    else
                    {
                        try
                        {
                            cmd.CommandText = "update service set vehicle = '" + row["vehicle"] + "', dateService = '" + row["dateService"] + "' where id = " + row["id"] + "";
                            cmd.ExecuteNonQuery();
                            LoadData();
                        }
                        catch (Exception ex)
                        {
                            MessageBox.Show(": " + ex.Message, "Επισήμανση", MessageBoxButton.OK, MessageBoxImage.Warning);
                        }
                        finally
                        {
                            con.Close();
                        }

                    }
                }

            }
            //else no selection
            else
            {
                MessageBox.Show("");
            }
    }
}