在ReactiveUI路由之后，如何将键盘焦点移动到视图

private IReactiveObject _focusElement;
public IReactiveObject FocusElement
{
    get => _focusElement;
    set => this.RaiseAndSetIfChanged(ref _focusElement, value);
}

this.Bind(ViewModel, vm => vm.FocusElement, v => v.MyInputElement)

this.WhenActivated(disposables =>
{
    Disposable.Create(() =>
    {
        // 在视图离开时取消焦点
        ViewModel.FocusElement = null;
    }).DisposeWith(disposables);

    this.WhenAnyValue(x => x.ViewModel.FocusElement)
        .Where(element => element != null)
        .Subscribe(element =>
        {
            // 将焦点移动到指定元素
            element.Focus();
        })
        .DisposeWith(disposables);
});