PropertyDefinitions are not part of the logical tree (they define a set of rules that is used by RadPropertyGrid to generate the respective fields and editors). So that, they neither have a DataContext, nor can use ElementName and RelativeSource bindings. You can set the Binding source to be your ViewModel and bind the IsReadOnly property to a property of the ViewModel. The generated editors has their ReadOnly (for TextBox) and IsEnabled (for other controls) bound, so that it is not recommended to do so. In case you need additional assistance, you can send a sample project that illustrates your scenario. We will do our best to debug it on our side and send you a modified version.