Question

I have set up my own user control which contains two ComboBoxes, each ComboBox item source is bound to a DependencyProperty. The issue I am having is passing a property from the form that uses my user control to the user control.

Below is my user control:

public static readonly DependencyProperty ListOneProperty = DependencyProperty.Register
    ("ListOne", typeof(List<int>), typeof(LinkedComboBox), new PropertyMetadata(new List<int>()));
    public List<int> ListOne
    {
        get { return (List<int>)GetValue(ListOneProperty); }
        set { SetValue(ListOneProperty, value); }
    }


    public static readonly DependencyProperty ListTwoProperty = DependencyProperty.Register
        ("ListTwo", typeof(List<string>), typeof(LinkedComboBox), new PropertyMetadata(new List<string>()));
    public List<string> ListTwo
    {
        get { return (List<string>)GetValue(ListTwoProperty); }
        set { SetValue(ListTwoProperty, value); }
    }


    public LinkedComboBox()
    {

        InitializeComponent();
        FillListOne();
    }

And below is my MainWindow xaml:

        <control:LinkedComboBox x:Name="LinkedBox" ListTwo="{Binding MyList}"/>

And MainWindow.xaml.cs:

    static List<string> _myList = new List<string>{"abc","efg"};
    public List<string> MyList 
    {
        get { return _myList; }
        set { _myList = value; } 
        }
    public MainWindow()
    {

        InitializeComponent();

    }

What do I need to get the User Control to accept a binding from the Main Window?

Answer 1

Everything is fine except that you need a PropertyChangedCallback to handle your property.

Here is a simple example

 public static readonly DependencyProperty ListTwoProperty = DependencyProperty.Register
    ("ListTwo", typeof(List<string>), typeof(LinkedComboBox), new PropertyMetadata(new List<string>(), new PropertyChangedCallback(Changed)));

 private static void Changed(DependencyObject d, DependencyPropertyChangedEventArgs e) 
 {  
   //e.NewValue here is your MyList in MainWindow.
 }