ComboBox binding to enum, what did I do wrong?

Question

I have searched around and it seems very easy to bind enums to combobox, just retrieve Enum values as a list of strings via an ObjectDataProvider from the static Enum.GetValues method, however i can't get it to work. The error is Type ContactExportType was not found.

I have an enum called ContactExportType, it resides on Enums class. This class is part of the CEM.Marketing.Objects namespace.

This is what i have:

<UserControl xmlns:local="clr-namespace:CEM.Marketing.Objects" xmlns:sys="clr-namespace:System;assembly=mscorlib"> <Grid> <Grid.Resources> <ObjectDataProvider MethodName="GetValues" ObjectType="{x:Type sys:Enum}" x:Key="ContactExportTypes"> <ObjectDataProvider.MethodParameters> <x:Type TypeName="local:ContactExportType" /> </ObjectDataProvider.MethodParameters> </ObjectDataProvider> </Grid.Resources> </Grid> <ComboBox ItemsSource="{Binding {StaticResource ContactExportTypes}}" ...

Thanks, Angela

Thanks Chris for your help. I couldn't do it in XAML after trying different things. Seems like it does not support one level down in the class structure. What I did to make it work is to bind the itemSource in code behind. combobox.ItemsSource = Enum.GetValues(typeof (Enums.ContactExportType)); — Angela
– Angela, Commented May 18, 2009 at 16:32

Thomas Levesque · Accepted Answer · 2009-05-18 22:46:21Z

To access a nested type, you should use the "+" separator :

<ObjectDataProvider MethodName="GetValues" ObjectType="{x:Type sys:Enum}" x:Key="ContactExportTypes"> <ObjectDataProvider.MethodParameters> <x:Type TypeName="local:Enums+ContactExportType" /> </ObjectDataProvider.MethodParameters> </ObjectDataProvider>

By the way, there is a simpler way to bind to the values of an enum, without using an ObjectDataProvider. It's based on a custom markup extension :

<ComboBox ItemsSource="{local:EnumValues local:Enums+ContactExportType}"/>

Here is the code for the EnumValues markup extension :

[MarkupExtensionReturnType(typeof(object[]))] 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) { if (this.EnumType == null) throw new ArgumentException("The enum type is not set"); return Enum.GetValues(this.EnumType); } }

@gonzobrains, what do you mean "not local" ? In the example above, local is just an XML namespace prefix mapped to the CLR namespace where the enum is defined. You can use any prefix and map it to any CLR namespace.

Muad'Dib · Accepted Answer · 2009-05-18 15:50:55Z

<ObjectDataProvider MethodName="GetValues" ObjectType="{x:Type local:Enums}" x:Key="ContactExportTypes">

should be

<ObjectDataProvider MethodName="GetValues" ObjectType="{x:Type sys:Enum}" x:Key="ContactExportTypes">

and

<x:Type TypeName="local:ContactExportType" />

should be

<x:Type TypeName="CEM.Marketing.Objects.ContactExportType"/>

the sys:Enum points to the Enum framework class the typename in the parameter points to your fully qualified type-name.

check Bea Stollnitz's blog

 <ObjectDataProvider MethodName="GetValues" ObjectType="{x:Type sys:Enum}" x:Key="odp"> <ObjectDataProvider.MethodParameters> <x:Type TypeName="namespace.class.TShirtSizes"/> </ObjectDataProvider.MethodParameters> </ObjectDataProvider> <ComboBox ItemsSource="{Binding Source={StaticResource odp}}" IsSynchronizedWithCurrentItem="true"/>

If TShirtSizes is in different class and namespace, how do you specify it? See my code... Thanks, Angela
you have to add an xmlns namespace to referance it---- xmlns:myenum="assembly;..."
your local xmlns is fine (assuming that is where you enum is at)
I changed ObjectType="{x:Type local:Enums}" to ObjectType="{x:Type sys:Enum}", still the same problem..
change your <x:Type TypeName="local:ContactExportType" /> to "CEM.Marketing.Objects.ContactExportType"

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