MvvmCross从ViewModel事件导航 [英] MvvmCross Navigate From ViewModel Event

问题描述

我从这里阅读有关从ViewModel到ViewModel的导航"和"View Model Lifecycle"的信息: https://github.com/MvvmCross/MvvmCross/wiki/ViewModel- -to-ViewModel-导航 https://github.com/MvvmCross/MvvmCross/wiki/View-Model-Lifecycle

I read about "ViewModel to ViewModel navigation" and "View Model Lifecycle" from here: https://github.com/MvvmCross/MvvmCross/wiki/ViewModel--to-ViewModel-navigation https://github.com/MvvmCross/MvvmCross/wiki/View-Model-Lifecycle

我可以使用Init()或Start()方法来初始化当前的ViewModel. 同样，我可以将参数从一个ViewModel传递到另一个ViewModel，并通过Init()方法接收它.

I can use Init() or Start() methods to initialise current ViewModel. Also I can pass parameters from one ViewModel to another and receive it in the Init() method.

所以我的问题是: 创建Windows Phone应用程序时，我使用了"NavigateTo"和"NavigateFrom"方法. Init()类似于"NavigateTo". 但是我没有在mvvmcross中找到"NavigateFrom"方法的替代方法，并且当我通过"Close(this)"或在Windows Phone上使用后退"按钮移动后退"时，我也不知道如何重新加载数据.

So my question: When I created windows phone apps I used "NavigateTo" and "NavigateFrom" methods. Init() is similar to "NavigateTo". But I didn't find alternative for "NavigateFrom" method in mvvmcross and I don't know how to reload data when I move 'back' by "Close(this)" or using back button on windows phone.

你能提示我吗?

提前谢谢！

已更新

我发现Messenger(MvvmCross插件)可以帮助我通知第一个ViewModel，而另一个第二个ViewModel更改了数据(例如，将一个项添加到集合中). 因此，当第二个ViewModel添加新项时，第一个ViewModel会在OnCollectionChanged(CollectionChangedMessage obj)方法中重新加载数据.

I found out that Messenger (MvvmCross plugin) can help me with informing first ViewModel, when an other second ViewModel has changed data (for example add an item to a collection). So when the second ViewModel add a new item, first ViewModel reloads the data in the OnCollectionChanged(CollectionChangedMessage obj) method.

Stuart在NPlus1DaysOfMvvmCross/N-13-CollectABull-Part2中展示了如何使用此插件. 链接到这里: https://github.com/MvvmCross/NPlus1DaysOfMvvmCross/tree/master/N-13-CollectABull-Part2

Stuart showed how to work with this plugin in the NPlus1DaysOfMvvmCross/N-13-CollectABull-Part2. Link here: https://github.com/MvvmCross/NPlus1DaysOfMvvmCross/tree/master/N-13-CollectABull-Part2

推荐答案

但是我没有在mvvmcross中找到"NavigateFrom"方法的替代方法，并且当我通过"Close(this)"或在Windows Phone上使用后退"按钮移动后退"时，我也不知道如何重新加载数据.

But I didn't find alternative for "NavigateFrom" method in mvvmcross and I don't know how to reload data when I move 'back' by "Close(this)" or using back button on windows phone.

通常，您无需在此事件中重新加载数据-因为ViewModel已在前向导航中从前一个导航创建并初始化.

In general, you don't need to reload data in this event - because the ViewModel is already created and initialised from the previous navigation in the forwards direction.

如果您确实想在导航时进行ViewModel的刷新，则N = 42视频中的IVisible模式可能会有所帮助，但您需要自己将其添加到View和ViewModel中-请参见 http://slodge.blogspot .co.uk/2013/11/n42-is-my-viewmodel-visible-can-i-kill.html

If you do want to do some refresh of the ViewModel when navigating back, then the IVisible pattern in the N=42 video may help but you'll need to add this to your View and ViewModel yourself - see http://slodge.blogspot.co.uk/2013/11/n42-is-my-viewmodel-visible-can-i-kill.html

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