SingletonCommandTCommand - класс

public class SingletonCommand<TCommand> : IRoutedCommand
where TCommand : new(), SingletonCommand<TCommand>

Public Class SingletonCommand(Of TCommand As {New, SingletonCommand(Of TCommand)})
	Implements IRoutedCommand

generic<typename TCommand>
where TCommand : gcnew(), SingletonCommand<TCommand>
public ref class SingletonCommand : IRoutedCommand

type SingletonCommand<'TCommand when 'TCommand : new() and SingletonCommand<'TCommand>> =  
    class
        interface IRoutedCommand
    end