如何通过参数来导航视图模型与WinRT的Caliburn.Micro？ [英] How to pass parameter to navigated view model with WinRT Caliburn.Micro?

问题描述

我开发一个Windows应用商店使用的的WinRT Caliburn.Micro 的应用程式的游戏，我依靠导航框架。

I am developing a Windows Store apps game using WinRT Caliburn.Micro, and I am relying on the navigation framework.

我有视图模型的游戏的设置（确定玩家）和实际的游戏。当从设置导航的游戏，我想玩家收集传递给游戏视图模型。我怎样才能做到这一点。

I have view models for the game setup (define players) and the actual game. When navigating from the setup to the game, I want to pass the collection of players to the game view model. How can I do this?

示意性地，我的看法车型目前看起来是这样的：

Schematically, my view models currently look like this:

public class SetupGameViewModel : NavigationViewModelBase
{
    public SetupGameViewModel(INavigationService ns) : base(ns) { }

    public IObservableCollection<Player> Players { get; set; }

    public void StartGame()
    {
        // This is as far as I've got...
        base.NavigationService.NavigateToViewModel<GameViewModel>();

        // How can I pass the Players collection from here to the GameViewModel?
    }
}

public class GameViewModel : NavigationViewModelBase
{
    public GameViewModel(INavigationService ns) : base(ns) { }

    public ScoreBoardViewModel ScoreBoard { get; private set; }

    public void InitializeScoreBoard(IEnumerable<Player> players)
    {
        ScoreBoard = new ScoreBoardViewModel(players);
    }
}

在理想情况下，我想打电话给 InitializeScoreBoard GameViewModel 构造函数中>，但据我已经能够告诉它是不可能通过 SetupGameViewModel.Players 收集到 GameViewModel 构造。

Ideally, I would like to call InitializeScoreBoard from within the GameViewModel constructor, but as far as I have been able to tell it is not possible to pass the SetupGameViewModel.Players collection to the GameViewModel constructor.

INavigationService.NavigateToViewModel< T> （扩展）方法可以选择将一个 [对象]参数的说法，但这个参数似乎并没有达到视图模型构造导航到。我无法弄清楚如何显式调用 GameViewModel.InitializeScoreBoard 从 SetupGameViewModel.StartGame 方法的方法，因为相关的 GameViewModel 并没有在这一阶段被初始化。

The INavigationService.NavigateToViewModel<T> (extension) method optionally takes an [object] parameter argument, but this parameter does not seem to reach the view model constructor navigated to. And I cannot figure out how to explicitly call the GameViewModel.InitializeScoreBoard method from the SetupGameViewModel.StartGame method either, since the GameViewModel has not been initialized at this stage.

推荐答案

在年底我通过实施临时事件处理程序解决了这个。原来，我可以使用 NavigateToViewModel< T>（对象）超载通过玩家收集。

In the end, I solved this by implementing a temporary event handler. It turned out that I could use the NavigateToViewModel<T>(object) overload to pass the player collection.

从卡利微论坛和 MSDN文档我得到的印象是，这种做法是只有保证了原始类型的工作，虽然在我的情况我迄今没有发现任何问题，它。

From the Caliburn Micro discussion forum and MSDN documentation I get the impression that this approach is only guaranteed to work for "primitive" types, although in my scenario I have so far not detected any problems with it.

我的 SetupGameViewModel.StartGame 方法现在已经实现如下：

My SetupGameViewModel.StartGame method is now implemented as follows:

public void StartGame()
{
    base.NavigationService.Navigated += NavigationServiceOnNavigated;
    base.NavigationService.NavigateToViewModel<GameViewModel>(Players);
    base.NavigationService.Navigated -= NavigationServiceOnNavigated;
}

以及非常的临时连接 NavigationServiceOnNavigated 事件处理程序的实现如下：

And the very temporarily attached NavigationServiceOnNavigated event handler is implemented as follows:

private static void NavigationServiceOnNavigated(object sender, NavigationEventArgs args)
{
    FrameworkElement view;
    GameViewModel gameViewModel;
    if ((view = args.Content as FrameworkElement) == null || 
        (gameViewModel = view.DataContext as GameViewModel) == null) return;

    gameViewModel.InitializeScoreBoard(args.Parameter as IEnumerable<Player>);
}

不是真正的干净的解决方案我为努力，但至少它似乎的工作。

Not really the clean solution I had striven for, but at least it seems to work.

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