Set of RadioButton controls setting a WPF DependencyProperty via Binding

Question

I am tring to create a simple UserControl that contains a set of RadioButtons and then sets a single DependencyProperty to a char value (each RadioButton has a unique char value associated with it). I'm taking my cue from this article http://wpftutorial.net/RadioButton.html which seemed to be an elegant solution, but I can't get it to work. Checking one of the RadioButtons does not change the Property. Neither of the ValueConverter's methods are ever called. There are no compile-time errors or binding errors at run-time. What am I missing?

Here is my XAML:

<UserControl x:Class="TestClientWpf.OrderTypePicker"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:TestClientWpf="clr-namespace:TestClientWpf">
<WrapPanel>
    <WrapPanel.Resources>
        <TestClientWpf:CharMatchToBooleanConverter x:Key="converter" />
    </WrapPanel.Resources>
    <RadioButton IsChecked="{Binding Path=OrderType, Mode=TwoWay, Converter={StaticResource converter}, ConverterParameter=1}">Type 1</RadioButton>
    <RadioButton IsChecked="{Binding Path=OrderType, Mode=TwoWay, Converter={StaticResource converter}, ConverterParameter=2}">Type 2</RadioButton>
    <RadioButton IsChecked="{Binding Path=OrderType, Mode=TwoWay, Converter={StaticResource converter}, ConverterParameter=3}">Type 3</RadioButton>
</WrapPanel>
</UserControl>

My code behind:

public partial class OrderTypePicker
{
    public static readonly DependencyProperty OrderTypeProperty = DependencyProperty.Register("OrderType", typeof(char), typeof(OrderTypePicker), new FrameworkPropertyMetadata('1'));

    public char OrderType
    {
        get { return (char)GetValue(OrderTypeProperty); }
        set { SetValue(OrderTypeProperty, value); }
    }

    public OrderTypePicker()
    {
        InitializeComponent();
    }
}

My ValueConverter:

public class CharMatchToBooleanConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value == null || parameter == null)
            return false;

        string checkValue = value.ToString();
        string targetValue = parameter.ToString();
        return checkValue.Equals(targetValue, StringComparison.InvariantCultureIgnoreCase);
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value == null || parameter == null)
            return null;

        bool useValue = (bool)value;
        string targetValue = parameter.ToString();
        return useValue ? char.Parse(targetValue) : (char?) null;
    }

Answer 1

In a UserControl your DataContext still points to the normal DataContext of its parent.

You need to bind to properties on the control itself, so:

<RadioButton IsChecked="{Binding RelativeSource={RelativeSource AncestorType={x:Type UserControl}}, Path=OrderType, Mode=TwoWay, Converter={StaticResource converter}, ConverterParameter=1}">Type 1</RadioButton>

Answer 2

Refer this link if you need explaantion WPF Tutorial

Or you can use

  `Radio1.GroupName = Radio2.GroupName = this.GetHashCode().ToString() + Radio1.GroupName;`

Answer 3

For the record, a colleague of mine also provided an alternative solution: to set the DataContext property to the UserControl instance (for example in the constructor):

    public OrderTypePicker()
    {
        InitializeComponent();
        DataContext = this;
    }