如何使用ViewModelCloser关闭ViewModel的视图? [英] How to use ViewModelCloser to close the View of the ViewModel?

问题描述

在MvvmCross v3(客户管理)示例中，方法void RequestClose(IMvxViewModel viewModel)关闭顶部的View.您如何代替ViewModel的View?

In the MvvmCross v3, CustomerManagement example, the method void RequestClose(IMvxViewModel viewModel) closes the top View. How do you close the View of a ViewModel instead?

推荐答案

我不会使用该ViewModelCloser方法-尽管您可以根据需要扩展它.

I wouldn't use that ViewModelCloser method - although it could be extended if you want to.

MvvmCross v3删除了以前的CloseViewModel方法-因为它不能在所有平台和所有演示样式上都真正起作用-在所有导航控制器，拆分视图，选项卡，弹出窗口，弹出窗口，对话框等中都可以使用.

MvvmCross v3 removed the previous CloseViewModel method - because it didn't really work across all platforms and across all presentation styles - across all of navigation controllers, splitviews, tabs, flyouts, popups, dialogs, etc.

要替换它，v3引入了一个新的ViewModel调用:

To replace it, v3 introduces a new ViewModel call:

    protected bool ChangePresentation(MvxPresentationHint hint)

这在UI中使用IMvxViewPresenter方法进行了匹配:

This is matched in the UIs with an IMvxViewPresenter method:

    void ChangePresentation(MvxPresentationHint hint);

要使用此功能，您需要:

To use this, you will need to:

1. 创建一个新的提示类-例如public class CustomPresentationHint : MvxPresentationHint { /* ... */ }

在每个UI项目中，提供一个自定义演示者(通常通过覆盖Setup.cs类中的CreateViewPresenter())-在该自定义演示者中处理ChangePresentationHint调用:

In each UI project, provide a custom presenter (normally by overriding CreateViewPresenter() in your Setup.cs class) - and in that custom presenter handle the ChangePresentationHint call:

      public void ChangePresentation(MvxPresentationHint hint)
      {
          if (hint is CustomPresentationHint)
          {
               // your custom actions here
               // - which may involve interacting with the RootFrame, with a NavigationController, with the AndroidFragment manager, etc
          }
      }

在您的视图模型中，您可以在需要时发送CustomPresentationHint.

我意识到这比vNext所需的工作更多，但希望它是一种更灵活，更强大的方法.

I realise this is 'more work' than was required in vNext, but hopefully it's a more flexible, powerful approach.

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