How come my databinding is writing out the Length property?

Question

So I've setup a viewmodel to where it binds an ObservableCollection<string> to my DataGrid.

It prints out the value just fine but it also prints out the Length of the property? I don't recall ever setting that in any binding whatsoever. Why is it doing that?

My MainWindow.cs

public MainWindow()
{
    InitializeComponent();
    DataContext = new MasterViewModel();
}

MasterViewModel.cs

class MasterViewModel
{
    public Users Users { get; } = new Users();
    public Achievements Achievements { get; } = new Achievements();
}

Users.cs

class Users : INotifyPropertyChanged
{
    public Users()
    {
        newList.Add("Hello there");
    }

    private ObservableCollection<string> newList = new ObservableCollection<string>();

    public ObservableCollection<string> NewList
    {
        get { return newList; }
        set { newList = value; }
    }


    public event PropertyChangedEventHandler PropertyChanged;
    private void OnPropertyChanged(string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

XAML

<DataGrid ItemsSource="{Binding Users.NewList}" Width="400" Height="200" Margin="182,158,210,61">
    <DataGrid.Columns>
        <DataGridTemplateColumn>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding}"></TextBlock>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

Answer 1

DataGrid has property AutoGenerateColumns which is set to True by default and makes DataGrid to create a column for each property defined in items.

DataGrid is bound to NewList which contains items of type string which has Length property. So it makes Length column

you can disable auto-generation by setting <DataGrid AutoGenerateColumns="False" ...