WPF : Binding a combo-box to an enum property of a class object?

Question

In the namespace X, I've got a public enum definition :

namespace X
{
    public enum MyEnum
    { val0=0, val1, val2, val3, val4 }
}

In the namespace Y I've got a class which has a property of the X.MyEnum type

using namespace X;
namespace Y
{
    class Container
    {
        public MyEnum MYEnum
        { get { return m_myenum; } set { m_myenum = value; } }

        private MyEnum m_myenum;
    }
}

I've created an user control which contains a combo-box. I'd very much like to databind it (TwoWay) to the MYEnum field of the "Container". The usercontrol resides in the window.

How do I achieve that ? I've seen some examples with ObjectDataProvider, however I'm lost.

Answer 1

You can define the ItemsSource of the ComboBox by using a custom markup extension that returns all values of the enum (this achieves the same result as using an ObjectDataProvider, but it is simpler to use) :

[MarkupExtensionReturnType(typeof(Array))]
public class EnumValuesExtension : MarkupExtension
{
    public EnumValuesExtension()
    {
    }

    public EnumValuesExtension(Type enumType)
    {
        this.EnumType = enumType;
    }

    [ConstructorArgument("enumType")]
    public Type EnumType { get; set; }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return Enum.GetValues(EnumType);
    }
}

And bind the SelectedItem to your MYEnum property :

<ComboBox ItemsSource="{local:EnumValues local:MyEnum}" SelectedItem="{Binding MYEnum, Mode=TwoWay}" />

(the local XML namespace must be mapped to your C# namespace)