WPF User Control - multiple dependency propertyies

See more:

WPF

It's late and the answer is probably something simple so apologies if this is a dumb question.

I have a user control, it had a single dependency property which is set via a binding which works fine.

I then added two more but the new two (which are setup exactly the same as the first) will not populate from XAML. They always contain their default values (null/0.0).

User control:

public partial class MyUserControl : UserControl
{
    public static readonly DependencyProperty WorkingValueProperty;
    public static readonly DependencyProperty VarBValueProperty;
    public static readonly DependencyProperty VarCValueProperty;
    public MyUserControl()
    {
        InitializeComponent();
    }
    static MyUserControl()
    {
        FrameworkPropertyMetadata WorkingValueMetadata = new FrameworkPropertyMetadata(new PropertyChangedCallback(WorkingValuePropertyChanged));
        FrameworkPropertyMetadata VarBValueMetadata = new FrameworkPropertyMetadata();
        FrameworkPropertyMetadata VarCValueMetadata = new FrameworkPropertyMetadata();
        MyUserControl.WorkingValueProperty = DependencyProperty.Register("WorkingValue", typeof(double), typeof(MyUserControl), WorkingValueMetadata);
        MyUserControl.VarBValueProperty = DependencyProperty.Register("VarBValue", typeof(double), typeof(MyUserControl), VarBValueMetadata);
        MyUserControl.VarCValueProperty = DependencyProperty.Register("VarCValue", typeof(string), typeof(MyUserControl), VarCValueMetadata);
    }
    public double WorkingValue
    {
        get
        {
            return (double)GetValue(WorkingValueProperty);
        }
        set
        {
            SetValue(WorkingValueProperty, value);
        }
    }
    public double VarBValue
    {
        get
        {
            return (double)GetValue(VarBValueProperty);
        }
        set
        {
            SetValue(VarBValueProperty, value);
        }
    }
    public string VarCValue
    {
        get
        {
            return (string)GetValue(VarCValueProperty);
        }
        set
        {
            SetValue(VarCValueProperty, value);
        }
    }
    private static void WorkingValuePropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
    {
        MyUserControl myUC = (MyUserControl)o;
    ...

    }

XAML:

<ic:myusercontrol workingvalue="{Binding AnotherValue, UpdateSourceTrigger=PropertyChanged}" varcvalue="Binding AnotherValue, UpdateSourceTrigger=PropertyChanged}" xmlns:ic="#unknown">
                     VarBValue="200"/></ic:myusercontrol>

The user control is in a DataTemplate which is used in a listbox. It's not really meant to be bound to the same value as the first field but I know for sure that one works as it's populating the first property fine. If I create the control and just hard code the value all the properties populate fine so it's something to do with it being in a list but I can't figure it out.

I'm looking at the values in call back WorkingValuePropertyChanged (it's there for another purpose but it seemed a reasonable place to check). WorkingValueProperty is populated and the other two are null and 0.0 respectively.

Thanks in advance.

Bob