I have a databound button that has a TargetNullValue: <Button Content={Binding Path=NextItem, Mode=OneWay, TargetNullValue=’None’}

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Asked: May 19, 20262026-05-19T00:57:30+00:00 2026-05-19T00:57:30+00:00

I have a databound button that has a TargetNullValue: <Button Content={Binding Path=NextItem, Mode=OneWay, TargetNullValue=’None’}

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I have a databound button that has a TargetNullValue:

<Button Content="{Binding Path=NextItem, Mode=OneWay, TargetNullValue='None'}" />

That works fine, and when NextItem is null, the button shows “None.” But I want to bind the null value to something.

To simplify things, let’s assume that I have a property on my ViewModel called NullValue that returns a string that I want to be bound to when null:

<Button Content="{Binding Path=NextItem, Mode=OneWay, TargetNullValue={Binding Path=NullValue}}" />

But this throws:

System.Windows.Markup.XamlParseException: Provide value on 'System.Windows.Data.Binding' threw an exception. [Line: 129 Position: 92] 
---> System.InvalidOperationException: Operation is not valid due to the current state of the object.
at MS.Internal.XamlManagedRuntimeRPInvokes.TryApplyMarkupExtensionValue(Object target, XamlPropertyToken propertyToken, Object value)
at MS.Internal.XamlManagedRuntimeRPInvokes.SetValue(XamlTypeToken inType, XamlQualifiedObject& inObj, XamlPropertyToken inProperty, XamlQualifiedObject& inValue)

What I really want to do is bind the null value to a resx, so I have that in the control’s resource dictionary and change the binding like so:

<res:AppResources x:Key="appResources" />
...
<Button Content="{Binding Path=NextItem, Mode=OneWay, TargetNullValue={Binding Path=NullValue,Source={StaticResource appResources}}}" />

This also throws the same exception. Any suggestions?