WPF

<h1>region MyItems Collection</h1>

public static readonly DependencyProperty MyItemsProperty =
        DependencyProperty.RegisterAttached("MyItems",
                        typeof(List<string>),
                        typeof(MyClass),
                        new UIPropertyMetadata(null,
                                new PropertyChangedCallback(OnMyItemsChanged)));

public static List<string> GetMyItems(DependencyObject obj)
{
    return (List<string>)obj.GetValue(RightsKeyProperty);
}

public static void SetMyItems(DependencyObject obj, List<string> value)
{
    obj.SetValue(MyItemsProperty, value);
}

private static void OnMyItemsChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
}
<h1>endregion</h1>

<blockquote class="quote"><div class="op">Quote:</div><TextBox Grid.Row="1"
            Grid.Column="1"
            Text="{Binding CreditLimit, Mode=TwoWay}"
            Width="100"
            sec:MyClass.MyItems=""   <!--HOW DO I ASSIGN MULTIPLE ITEMS HERE-->
            HorizontalAlignment="Left"
            Margin="10"/>
</blockquote>

public FooClickArgs(NFoo pos, NFoo2 part, MouseEventArgs e)
				: base(e.Button, e.Clicks, e.X, e.Y, e.Delta)
			{
				Position = pos;
				PositionPart = part;
			}

public partial class MainWindow : Window, INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    // Dictionary of rights
    private Dictionary<string, bool> _Rights;
    public Dictionary<string, bool> Rights
    {
        get { return _Rights; }
        set
        {
            if (_Rights != value)
            {
                _Rights = value;
                RaisePropertyChanged("Rights");
            }
        }
    }

    // Bound data. Could be defined here or on a model
    private double _CreditLimit;
    public double CreditLimit
    {
        get { return _CreditLimit; }
        set
        {
            if (_CreditLimit != value)
            {
                _CreditLimit = value;
                RaisePropertyChanged("CreditLimit");
            }
        }
    }

    public MainWindow()
    {
        InitializeComponent();

        this.DataContext = this;

        // The property bound to the textbox's Test property
        CreditLimit = 125000;

        // Dictionary of rights
        Rights = new Dictionary<string, bool>();
        Rights.Add("creditLimit", false); // The user cannot access the Credit Limit textbox
    }

    private void RaisePropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

<TextBox Text="{Binding CreditLimit, Mode=TwoWay}"
            IsEnabled="{Binding Rights[creditLimit]}"
            Width="100"
            HorizontalAlignment="Left"
            Margin="10"/>

Rights["creditLimit"] = true;
RaisePropertyChanged("Rights");

1. The user has rights to modify the credit limit
2. The customer is in good standing (their credit is still good)
3. The customer does not have a balance