Edit

Share via

How to bind to an enumeration

  • Article

This example shows how to bind to an enumeration. Unfortunately there isn't a direct way to use an enumeration as a data binding source. However, the Enum.GetValues(Type) method returns a collection of values. These values can be wrapped in an ObjectDataProvider and used as a data source.

The ObjectDataProvider type provides a convenient way to create an object in XAML and use it as a data source.

Reference the enumeration

Use the ObjectDataProvider type to wrap an array of enumeration values provided by the enumeration type itself. The following steps wrap a HorizontalAlignment enumeration. You can substitute a different enumeration if desired.

  1. Create a new ObjectDataProvider as a XAML resource, either in your application XAML or the XAML of the object you're working with. This example uses a window and creates the ObjectDataProvider with a resource key of EnumDataSource.

    <Window.Resources>
    <ObjectDataProvider x:Key="EnumDataSource"
                        ObjectType="{x:Type sys:Enum}"
                        MethodName="GetValues">
        <ObjectDataProvider.MethodParameters>
            <x:Type TypeName="HorizontalAlignment" />
        </ObjectDataProvider.MethodParameters>
    </ObjectDataProvider>
</Window.Resources>

    In this example, the ObjectDataProvider uses three properties to retrieve the enumeration:

    Property Description
    ObjectType The type of object to be returned by the data provider. In this example, System.Enum. The sys: XAML namespace is mapped to System.
    MethodName The name of the method to run on the System.Enum type. In this example, Enum.GetValues.
    MethodParameters A collection of values to provide to the MethodName method. In this example, the method takes the System.Type of the enumeration.

    Effectively, the XAML is breaking down a method call, method name, parameters, and the return type. The ObjectDataProvider configured in the previous example is the equivalent of the following code:

    var enumDataSource = System.Enum.GetValues(typeof(System.Windows.HorizontalAlignment));

    Dim enumDataSource = System.Enum.GetValues(GetType(System.Windows.HorizontalAlignment))

  2. Reference the ObjectDataProvider resource. The following XAML lists the enumeration values in a ListBox control:

    <ListBox Name="myComboBox" SelectedIndex="0"
         ItemsSource="{Binding Source={StaticResource EnumDataSource}}"/>

Full XAML

The following XAML code represents a simple window that does the following:

  1. Wraps the HorizontalAlignment enumeration in a ObjectDataProvider data source as a resource.
  2. Provides a ListBox control to list all enumeration values.
  3. Binds a Button control's HorizontalAlignment property to the selected item in the ListBox.
<Window x:Class="ArticleExample.BindEnumFull"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:sys="clr-namespace:System;assembly=mscorlib" 
        SizeToContent="WidthAndHeight"
        Title="Enum binding">
    <Window.Resources>
        <ObjectDataProvider x:Key="EnumDataSource"
                            ObjectType="{x:Type sys:Enum}"
                            MethodName="GetValues">
            <ObjectDataProvider.MethodParameters>
                <x:Type TypeName="HorizontalAlignment" />
            </ObjectDataProvider.MethodParameters>
        </ObjectDataProvider>
    </Window.Resources>
    
    <StackPanel Width="300" Margin="10">
        <TextBlock>Choose the HorizontalAlignment value of the Button:</TextBlock>

        <ListBox Name="myComboBox" SelectedIndex="0"
                 ItemsSource="{Binding Source={StaticResource EnumDataSource}}"/>

        <Button Content="I'm a button"
                HorizontalAlignment="{Binding ElementName=myComboBox, Path=SelectedItem}" />
    </StackPanel>
</Window>

See also