<Button x:Name="button1" Content="open project" Command="{Binding ButtonClick}"/> 

class DelegateCommand : public BaseCommand {
public:
    typedef Delegate<void(BaseComponent*)> Action;
    DelegateCommand(const Action& action) : BaseCommand(NsSymbol::Null(), 0), _action(action) {}
    NsBool CanExecute(BaseComponent* param) const {
        return true;
    }
    void Execute(BaseComponent* param) const {
        _action(param);
    }
private:
    Action _action;

    NS_IMPLEMENT_INLINE_REFLECTION(DelegateCommand, BaseCommand) {
        NsMeta<TypeId>("DelegateCommand");
    }
}; 

class ProjectSelect : public BaseComponent {
public:
    ProjectSelect() {
        mCommand = *new DelegateCommand(MakeDelegate(this, &ProjectSelect::ButtonClick));
    }
    void ButtonClick(BaseComponent* sender) {
        // <<== Never access this point !!! =======
    }
    DelegateCommand* GetButtonClickCommand() const {
        return mCommand.GetPtr();
    }
private:
    Ptr<DelegateCommand> mCommand;

    NS_IMPLEMENT_INLINE_REFLECTION(ProjectSelect, BaseComponent) {
        NsMeta<TypeId>("ProjectSelect");
        NsProp("ButtonClick", &ProjectSelect::GetButtonClickCommand);
    }
};