Typically you will create an instance of this as a resource. For example, one possible use of this converter: <go:NullBooleanConverter x:Key="theNullBooleanConverter" /> <ComboBox IsEnabled="{Binding Path=SelectedNode, ElementName=myDiagram, Converter={StaticResource theNullBooleanConverter}}"> When a node is selected, the ComboBox is enabled.
System.Object
Northwoods.GoXam.Converter
Northwoods.GoXam.NullBooleanConverter