Enumerations are often used in applications to enable the user to select an item from a list of predefined values. This can be handled in the ViewModel by publishing a list of the enum values. But there is also another way that uses a XAML only approach.
Example:
public enum SampleEnum
{
Dog, Cat, Bird
}
In the resources of the window a data source will be created, which calls the GetValues method of the System.Enum class in order to obtain a list of enum values:
<Window x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:System="clr-namespace:System;assembly=mscorlib"
xmlns:local="clr-namespace:WpfApplication1"
Title="Bind to Enum" Height="250" Width="250">
<Window.Resources>
<ObjectDataProvider x:Key="dataFromEnum" MethodName="GetValues" ObjectType="{x:Type System:Enum}">
<ObjectDataProvider.MethodParameters>
<x:Type TypeName="local:SampleEnum"/>
</ObjectDataProvider.MethodParameters>
</ObjectDataProvider>
</Window.Resources>
</Window>
Binding to data source:
<ComboBox ItemsSource="{Binding Source={StaticResource dataFromEnum}}" />
As the values of enums are usually not in a human readable form, we might want to used a converter to convert the values into (localized) strings.
[ValueConversion(typeof(SampleEnum?), typeof(String))]
public class SampleEnumConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
switch (value as SampleEnum?) {
case SampleEnum.Dog:
return "Hund";
case SampleEnum.Cat:
return "Katze";
case SampleEnum.Bird:
return "Vogel";
}
return null;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
return DependencyProperty.UnsetValue;
}
}
How to use the converter:
<Window.Resources>
...
<myConverters:SampleEnumConverter x:Key="SampleEnumConverter"/>
</Window.Resources>
...
<ComboBox ItemsSource="{Binding Source={StaticResource dataFromEnum}}">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=., Converter={StaticResource SampleEnumConverter}}"/>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
The ItemsSource binding shown in previous example remains unchanged, but we now add a custom ItemTemplate to the ComboBox.
