Multiple selection in WPF MVVM ListBox

Question

I have a ListBox containing filenames. Now I need to get array of selected items from this ListBox. I found a few answers here, but none of them worked for me. I\'am using C

Answer 1

You can use this code for MVVM Pattern

XAML

<ListBox x:Name="DeleteHistoryListBoxItem" SelectedItem="{Binding Path=DeleteHistorySelectedItem,UpdateSourceTrigger=PropertyChanged}" 
         ItemsSource="{Binding DeleteHistoryListBox, NotifyOnSourceUpdated=True}" SelectionMode="Multiple">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Item}"/>
        </DataTemplate>
    </ListBox.ItemTemplate>
    <ListBox.ItemContainerStyle>
        <Style TargetType="{x:Type ListBoxItem}">
            <Setter Property="IsSelected" Value="{Binding Mode=TwoWay, Path=IsSelected}"/>
        </Style>
    </ListBox.ItemContainerStyle>
</ListBox>

ViewModel

private ObservableCollection<HistoryItems> deleteHistoryListBox = new ObservableCollection<HistoryItems>();
public ObservableCollection<HistoryItems> DeleteHistoryListBox
{
    get
    {
        return deleteHistoryListBox;
    }
    set
    {
        deleteHistoryListBox = value;
        this.RaisePropertyChanged("DeleteHistoryListBox");
    }
}

private HistoryItems deleteHistorySelectedItem;
public HistoryItems DeleteHistorySelectedItem
{
    get
    {
        return deleteHistorySelectedItem;
    }
    set
    {
        var selectedItems = DeleteHistoryListBox.Where(x => x.IsSelected).Count();
        this.RaisePropertyChanged("DeleteHistorySelectedItem");
    }
}

Class

public class HistoryItems : INotifyPropertyChanged
{
    private string item;

    public string Item
    {
        get { return item; }
        set
        {
            item = value;
            this.RaisePropertyChanged("Item");
        }
    }

    private bool isSelected;

    public bool IsSelected
    {
        get { return isSelected; }
        set
        {
            isSelected = value;
            this.RaisePropertyChanged("IsSelected");
        }
    }
}

Answer 2

You can add SelectionChanged event handler in code-behind, and update property for selected items in the ViewModel from there.

XAML:

    <ListBox x:Name="DeleteHistoryListBox" SelectedItem="{Binding Path=DeleteHistorySelectedItem}" 
             ItemsSource="{Binding DeleteHistoryListBox, NotifyOnSourceUpdated=True}" 
         SelectionMode="Multiple" SelectionChanged="DeleteHistoryListBox_SelectionChanged">
    </ListBox>

DeleteHistoryView.xaml.cs

private void DeleteHistoryListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
        DeleteHistoryViewModel vm = (DeleteHistoryViewModel)DataContext;

        foreach (string item in e.AddedItems)
        {
            vm.DeleteHistorySelectedItem.Add(item);
        }

        foreach (string item in e.RemovedItems)
        {
            vm.DeleteHistorySelectedItem.Remove(item);
        }
}