WPF How to bind an enum with Description to a ComboBox

Question

How can I bind an enum with Description (DescriptionAttribute) to a ComboBox?

I got an enum:

public enum ReportTemplate
{
    [Description("Top view")]
    TopView,

    [Description("Section view")]
    SectionView
}

I tried this:

<ObjectDataProvider MethodName="GetValues" ObjectType="{x:Type System:Enum}"
                    x:Key="ReportTemplateEnum">
    <ObjectDataProvider.MethodParameters>
        <x:Type TypeName="Helpers:ReportTemplate"/>
    </ObjectDataProvider.MethodParameters>
</ObjectDataProvider>

<Style x:Key="ReportTemplateCombobox" TargetType="dxe:ComboBoxEditSettings">
    <Setter Property="ItemsSource" 
            Value="{Binding Source={x:Type Helpers:ReportTemplate}}"/>
    <Setter Property="DisplayMember" Value="Description"/>
    <Setter Property="ValueMember" Value="Value"/>
</Style>

Can't succeed to do this, any simple solution?

Thanks in advance!

Answer 1

This can be done by using a converter and item template for your comboBox.

Here is the converter code which when bound to an enum will return the Description value:

namespace FirmwareUpdate.UI.WPF.Common.Converters
{
    public class EnumDescriptionConverter : IValueConverter
    {
        private string GetEnumDescription(Enum enumObj)
        {
            FieldInfo fieldInfo = enumObj.GetType().GetField(enumObj.ToString());

            object[] attribArray = fieldInfo.GetCustomAttributes(false);

            if (attribArray.Length == 0)
            {
                return enumObj.ToString();
            }
            else
            {
                DescriptionAttribute attrib = attribArray[0] as DescriptionAttribute;
                return attrib.Description;
            }
        }

        object IValueConverter.Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            Enum myEnum = (Enum)value;
            string description = GetEnumDescription(myEnum);
            return description;
        }

        object IValueConverter.ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return string.Empty;
        }
    }
}

Then in your xaml you need to use and item template.

<ComboBox Grid.Row="1" Grid.Column="1"  Height="25" Width="100" Margin="5"
              ItemsSource="{Binding Path=MyEnums}"
              SelectedItem="{Binding Path=MySelectedItem}"
              >
        <ComboBox.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding Converter={StaticResource enumDescriptionConverter}}"/>
            </DataTemplate>
        </ComboBox.ItemTemplate>
    </ComboBox>

Answer 2

RSmaller has a good answer, and is the one I use as well, with one caveat. If you have more than one attribute on your enums, and Description isn't the first listed then his "GetEnumDescription" method will throw an exception...

Here is a slightly safer version:

    private string GetEnumDescription(Enum enumObj)
    {
        FieldInfo fieldInfo = enumObj.GetType().GetField(enumObj.ToString());

        object[] attribArray = fieldInfo.GetCustomAttributes(false);

        if (attribArray.Length == 0)
        {
            return enumObj.ToString();
        }
        else
        {
            DescriptionAttribute attrib = null;

            foreach( var att in attribArray)
            {
                if (att is DescriptionAttribute)
                    attrib = att as DescriptionAttribute;
            }

            if (attrib != null )
                return attrib.Description;

            return enumObj.ToString();
        }
    }