DataGridRowEditEndingEventArgs 's row.item returning null

Question

I just created a new WPF MVVMLight Project, simple :

MainWindow.xaml

<Window x:Class="DG.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
        xmlns:command="http://www.galasoft.ch/mvvmlight"            
        DataContext="{Binding Main, Source={StaticResource Locator}}">

    <i:Interaction.Triggers>
        <i:EventTrigger EventName="Loaded">
            <command:EventToCommand Command="{Binding Loaded}"/>
        </i:EventTrigger>
    </i:Interaction.Triggers>

    <Grid>    
        <DataGrid ItemsSource="{Binding Personnes, UpdateSourceTrigger=PropertyChanged}" AutoGenerateColumns="True"                      CanUserAddRows="True" CanUserDeleteRows="True">
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="RowEditEnding">
                    <command:EventToCommand Command="{Binding RowEditEnding}" PassEventArgsToCommand="True"/>
                </i:EventTrigger>
            </i:Interaction.Triggers>    
        </DataGrid>    
    </Grid>
</Window>

Main (the ViewModel)

public class MainViewModel : ViewModelBase
    {
        public RelayCommand Loaded
        {
            get
            {
                return new RelayCommand(() =>
                {
                    Personnes = new ObservableCollection<Personne>();
                    Personnes.Add(new Personne("Daoudi", "25"));
                    Personnes.Add(new Personne("Aymen", "26"));
                });
            }
        }

        public RelayCommand<DataGridRowEditEndingEventArgs> RowEditEnding
        {
            get
            {
                return new RelayCommand<DataGridRowEditEndingEventArgs>((e) =>
                {
                    int i = 5;
                });
            }
        }

        public ObservableCollection<Personne> Personnes
        {
            get { return _personnes; }
            set
            {
                _personnes = value;
                RaisePropertyChanged("Personnes");
            }
        }

        private ObservableCollection<Personne> _personnes; 
        public MainViewModel()
        {
           
        }            
    }

Personne class

public class Personne
    {
        public string Name { get; set; }
        public string Age { get; set; }

        public Personne ()
        {
            
        }

        public Personne(string name, string age)
        {
            Name = name;
            Age = age;
        }
    }

When trying to add a new row, in the RowEditEnding , the e.Row.item shows null :

Why is this happening ?

Note : I tried both ObservableColletion and BindingList for the Peronnes list, and tried both PropertyChanged and LostFocus for the UpdateSourceTrigger in the binding of the ItemsSource of the DataGrid, always same result !

Answer 1

It seems that you need to specify the columns manually and precise the UpdateSourceTrigger, this should work normally !

 <DataGrid HorizontalAlignment="Left" Margin="0,10,0,0" AutoGenerateColumns="False" ItemsSource="{Binding Personnes}" VerticalAlignment="Top" Height="148" Width="282"
                      CanUserAddRows="True" CanUserDeleteRows="True">
                <DataGrid.Columns>
                    <DataGridTextColumn Header="Name" Binding="{Binding Name, UpdateSourceTrigger=LostFocus}"/>
                    <DataGridTextColumn Header="Age" Binding="{Binding Age, UpdateSourceTrigger=LostFocus}"/>
                </DataGrid.Columns>
...

So setting the AutoGenerateColumns="False" won't help achieve the result !