Binding Radiobuttons to their enumvalues without u

Question

I have a radio button group in a listview. The rows of this listview (which contain the radio button grp amongst other things) is an observable collection.

the code I have written goes something like this:

The Xaml:

    <RadioButton Content="EnumValueName1"
             GroupName="RadButGrp1"
             IsChecked="{Binding propertyName,Mode=TwoWay,Converter={StaticResource EnumToBoolConverter},ConverterParameter=EnumValueName1}" >
 </RadioButton>
 <RadioButton Content="EnumValueName2" 
              GroupName="RadButGrp1"
              IsChecked="{Binding propertyName,Mode=TwoWay,Converter={StaticResource EnumToBoolConverter},ConverterParameter=EnumValueName2}">
 </RadioButton>
<RadioButton Content="EnumValueName3" 
              GroupName="RadButGrp1"
              IsChecked="{Binding propertyName,Mode=TwoWay,Converter={StaticResource EnumToBoolConverter},ConverterParameter=EnumValueName3}">
 </RadioButton>

I am trying to bind directly to the data field called propertyName in my data structure defining the table that holds these values. I do NOT have this field in my ViewModel class for this view. I did this to avoid keeping track of the index of the collection that I am currently populating. (or so i'd like to think!)

The converter:

 public class EnumBooleanConverter : IValueConverter
 {
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        string parameterString = parameter as string;
        if (parameterString == null)
            return DependencyProperty.UnsetValue;

        if (value == null || Enum.IsDefined(value.GetType(), value) == false)
            return DependencyProperty.UnsetValue;

        object parameterValue = Enum.Parse(value.GetType(), parameterString);

        return parameterValue.Equals(value);
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        string parameterString = parameter as string;
        if (parameterString == null || value.Equals(false))
            return DependencyProperty.UnsetValue;

        return Enum.Parse(targetType, parameterString);
    }
 }

The problem is that in the ConvertBack function at the Enum.Parse line, the following Argument exception occurs:

Type provided must be an Enum. Parameter name: enumType

Is there a way to return an enum type to the binding? How do I tell the radio buttons which enumeration value it represents? How do I write a function that returns the appropriate enum value to the binding?

Hoping you guys can help. Thanks in advance!

Answer 1

Try this, it's my version of the EnumToBoolConverter:

public class EnumToBoolConverter : BaseConverterMarkupExtension<object, bool>
{
    public override bool Convert(object value, Type targetType, object parameter)
    {
        if (value == null)
            return false;

        return value.Equals(Enum.Parse(value.GetType(), (string)parameter, true));
    }

    public override object ConvertBack(bool value, Type targetType, object parameter)
    {
        return value.Equals(false) ? DependencyProperty.UnsetValue : parameter;
    }
}

Answer 2

Ok the solution was relatively simple once I got the concept right. I have done the following which partially solves my problem.

 <RadioButton Content="EnumValueName1" 
              GroupName="RadBtnGrp1"
              IsChecked="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ParentControl}},
                                  Path=DataContext.propName,
                                  Mode=TwoWay,
                                  Converter={StaticResource EnumToBoolConverter},ConverterParameter=EnumValueName1}">

 </RadioButton>

The targetType in my ConvertBack function now the correct enum type. Hope this helps!

Now i have to figure out how to make the radiobuttons retain selections in multiple rows of the listview. Presently they a selection in first row deselects the same group from the rest of the rows.

Thank you for your help so far. If anyone can point me to a solution for the new problem that would be really great!