c# MVVM how to refresh datagrid itemsource in the ViewModel

Question

I'm a beginner in C# and MVVM.

I have a datagrid and and I try to use a button Command to refresh it. but It doesn't work.

my XAML code

 <DataGrid ItemsSource="{Binding Src_ListeApplicationARV, Mode=TwoWay, NotifyOnSourceUpdated=True, UpdateSourceTrigger=PropertyChanged}"
        IsReadOnly="true" x:Name="Dt_ListeApplicationARV">

 <Button Name="btn_synchro" 
                    Style="{StaticResource MaterialDesignFloatingActionLightButton}"
                    Command="{Binding SynchroCommand}"
                    
                    materialDesign:ButtonProgressAssist.IsIndicatorVisible="{Binding IsSaving}"
                    materialDesign:ButtonProgressAssist.IndicatorForeground="DarkGoldenrod"
                    materialDesign:ButtonProgressAssist.Value="{Binding SaveProgress}"
                     
                    Width="35" HorizontalAlignment="Left" Margin="39,4,0,5" Cursor="Hand" Grid.Column="1" Height="35" Background="Transparent" BorderBrush="#6D92A0">
                <!-- simple example of toggling/animating pack icon with a data trigger-->
                <materialDesign:PackIcon Height="18" Width="19" Background="Transparent" Foreground="#6D92A0">
                            
                    <materialDesign:PackIcon.Style>
                        <Style TargetType="materialDesign:PackIcon">

                            <Setter Property="Kind" Value="CloudSyncOutline" />

                            <Style.Triggers>
                                <DataTrigger Binding="{Binding IsSaveComplete}" Value="false">
                                    <Setter Property="Kind" Value="CloudSyncOutline" />
                                </DataTrigger>
                                <DataTrigger Binding="{Binding IsSaveComplete}" Value="True">
                                    <Setter Property="Kind" Value="Check" />
                                   
                                    <DataTrigger.EnterActions>
                                        <BeginStoryboard Name="synchroboard">
                                            <Storyboard>
                                                <DoubleAnimation
                                                            Storyboard.TargetProperty="Opacity"
                                                            From="0"
                                                            To="1"
                                                            Duration="0:0:0.8" />
                                            </Storyboard>
                                            
                                        </BeginStoryboard>
                                  
                                    </DataTrigger.EnterActions>
                                   
                                </DataTrigger>
                            </Style.Triggers>
                          
                        </Style>
                    </materialDesign:PackIcon.Style>
                </materialDesign:PackIcon>
            </Button>
                 

and my code Behind

  public ListeLogiciels()
        {
            InitializeComponent();      
            DataContext = new ListeLogicielsViewModel();
           

        }

The ViewModel

 public class ListeLogicielsViewModel : ViewModelBase
    {

        public ICommand SynchroCommand { get; }

        public List<Models.ApplicationClient> Src_ListeApplicationARV
        {
            get { return LoadApplications(); }
            set
            {
                Src_ListeApplicationARV = LoadApplications();
                // Call OnPropertyChanged whenever the property is updated
                OnPropertyChanged("");
            }

         public ListeLogicielsViewModel()
        { 
            var Dt_ListeApplicationARV = this.LoadApplications();// get data in a list
         
            SynchroCommand = new AnotherCommandImplementation(_ => 
// reload dataSource
);
}

how to set my datagrid view with this Dt_ListeApplicationARV? it's just a stupid code, and I'm blocked. thanks for your help.

I'm trying to relaod a datagrid in a viewModel.

Answer 1

In WPF, when you want to display a list as a ItemsSource of a control you need to use an ObservableCollection instead of a List. It's a enumerable like the List but it auto-handle the NotifyCollectionChanged event.

Replace

        public List<Models.ApplicationClient> Src_ListeApplicationARV
        {
            get { return LoadApplications(); }
            set
            {
                Src_ListeApplicationARV = LoadApplications();
                // Call OnPropertyChanged whenever the property is updated
                OnPropertyChanged("");
            }

By

   public ObservableCollection<Models.ApplicationClient> Src_ListeApplicationARV {get; set;}

Don't forget to instantiate the ObservableCollection in the constructor.

With this, you just have to add or remove items to Src_ListeApplicationARV in your view model and it will automatically makes changes in the UI.

The OnPropertyChanged() must be used for a property and not a collection.
Example:

private string _name;
public string Name
{
    get { return _name; }
    set
    {
        _name = value;
        OnPropertyChanged(nameof(Name));
    }
}

Sorry for my english, I'm a French developer.