As evident from the error:
'ActionTest' property not found on 'object' ''MyUserControl' (Name='RadGridViewSettingsPersistenceControl')'
binding engine is searching for property in control and not in your ViewModel. (by default it searches for property in DataContext of control and i suspect you have set DataContext of control to itself somewhere in your code)
Use RelativeSource to get DataContext of your UserControl which will be your ViewModel.
LoadDataCommand="{Binding DataContext.ActionTest,
RelativeSource={RelativeSource Mode=FindAncestor,
AncestorType=UserControl}}"
Also instead of creating DP of type Action
, use ICommand
and create ICommand in your ViewModel and bind to it.