Wpf 带有 MvvmCross 的多个嵌套用户控件 [英] Wpf Multiple nested Usercontrols with MvvmCross

问题描述

我是 MvvmCross 的新手，但我使用 mvvm 有一段时间了.我知道如何用嵌套的用户控件组合用户控件.现在使用 mvvmcross 我不得不在另一个用户控件中显示两个或多个用户控件.除了 MvvmCross，我不使用任何其他框架.我的 Rootview 看起来像这样:

`<DockPanel><TextBlock Text="Root";DockPanel.Dock=顶部"/><ContentControl x:Name=MainMenuVM"内容={Binding MainMenuVM}"DockPanel.Dock=顶部"/></DockPanel></views:MvxWpfView>`

对应的ViewModel如下所示:

使用 MvvmCross.Commands;使用 MvvmCross.Logging；使用 MvvmCross.Navigation;使用 MvvmCross.ViewModels；命名空间 MvvmCrossTest.Core.ViewModels{公共类 RootViewModel:MvxNavigationViewModel{私有只读 IMvxViewModelLoader _mvxViewModelLoader；公共 RootViewModel(IMvxLogProvider logProvider, IMvxNavigationService navigationService, IMvxViewModelLoader mvxViewModelLoader) : base(logProvider, navigationService){_mvxViewModelLoader = mvxViewModelLoader;ShowMainMenu();}私有 MainMenuViewModel _mainMenuVM;public MainMenuViewModel MainMenuVM{得到 { 返回 _mainMenuVM;}放{SetProperty(ref _mainMenuVM, value);RaisePropertyChanged(() => MainMenuVM);}}公共 MvxCommand ShowMainMenuCommand { 获取；放;}公共无效 ShowMainMenu(){MainMenuVM = (MainMenuViewModel)_mvxViewModelLoader.LoadViewModel(MvxViewModelRequest.GetDefaultRequest(typeof(MainMenuViewModel)), null, null);}}}

我想在内容控件中显示的简化视图如下所示:

<网格></网格></views:MvxWpfView>

还有相应的 ViewModel.

使用 MvvmCross.Logging;使用 MvvmCross.Navigation;使用 MvvmCross.ViewModels；命名空间 MvvmCrossTest.Core.ViewModels{公共类 MainMenuViewModel : MvxNavigationViewModel{public MainMenuViewModel(IMvxLogProvider logProvider, IMvxNavigationService navigationService) : base(logProvider, navigationService){}}}

我看到的是MvvmCrossTest.Core.ViewModels.MainMenuViewModel"的文字，而不是 View/ViewModel.

我不想使用 Xamarin！

解决方案

我创建了一个项目，其中我向您展示一些基础知识.

简单

您可以在此处找到示例.>

RootView;

NestedView;

<网格><Label Content="Hello from NestedView";/></网格></views:MvxWpfView>

扩展(自定义演示者)

使用此自定义 wpf 演示器，您可以在容器中指定它们时轻松导航到视图.这样，您就可以在使用 mvvmcross 导航服务时从视图模型关闭和打开视图.

我从另一个项目复制了这个.您可以在我的示例项目此处中找到整个实现.

RootView;

<网格><标签内容=你好"/><ItemsControl region:MvxContainer.Id=RootViewRegion"/></网格></views:MvxWpfView>

后面的RootView代码；

[MvxContentPagePresentation(WrapInNavigationPage = true, NoHistory = false)]公共部分类 RootView:MvxWpfView{公共根视图(){初始化组件();}}

RootViewModel;

公共类RootViewModel:MvxNavigationViewModel{私有只读 IMvxNavigationService _navigationService;公共 IMvxAsyncCommand ShowNestedViewModelCommand { 获取；保护集；}公共 RootViewModel(IMvxLogProvider logProvider, IMvxNavigationService navigationService) : base(logProvider, navigationService){this._navigationService = 导航服务；//导航到嵌套视图this.ShowNestedViewModelCommand = new MvxAsyncCommand(() => this._navigationService.Navigate());ShowNestedViewModelCommand.Execute();}}

后面的NestedView代码；

[MvxWpfPresenter(RootViewRegion", mvxViewPosition.NewOrExsist)]公共部分类 NestedView : MvxWpfView{公共嵌套视图(){初始化组件();}}

很高兴知道

当您遇到导航和视图模型连接问题时，请使用后面的代码.它加载特定视图的视图模型；

[MvxContentPagePresentation(WrapInNavigationPage = true, NoHistory = false)]公共部分类 SomeView : MvxWpfView{公共 SomeView(){初始化组件();if (!(ViewModel 是 ViewModels.SomeViewModel)){if (Mvx.IoCProvider.TryResolve(out var someViewModel)){ViewModel = someViewModel;返回;}var _viewModelLoader = Mvx.IoCProvider.Resolve();var request = new MvxViewModelInstanceRequest(typeof(ViewModels.SomeViewModel));request.ViewModelInstance = _viewModelLoader.LoadViewModel(request, null);ViewModel = request.ViewModelInstance as ViewModels.SomeViewModel;Mvx.IoCProvider.RegisterSingleton(ViewModel);}}}

I'm pretty new in MvvmCross but I'm working with mvvm for awhile. I know how to compose usercontrols with nested usercontrols. Now with mvvmcross I got stucked to show two or more usercontrols in another usercontrol. I don't use any other framework than MvvmCross. My Rootview looks like this:

`<views:MvxWpfView
    x:Class="MvvmCrossTest.Wpf.Views.RootView"
    xmlns:views="clr-namespace:MvvmCross.Platforms.Wpf.Views;assembly=MvvmCross.Platforms.Wpf"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
    mc:Ignorable="d" 
    d:DesignHeight="450" d:DesignWidth="800">

    <DockPanel>  
        <TextBlock Text="Root" DockPanel.Dock="Top"/>
        <ContentControl x:Name="MainMenuVM" Content="{Binding MainMenuVM}" DockPanel.Dock="Top" />
    </DockPanel>
</views:MvxWpfView>`

The corresponding ViewModel looks like this:

using MvvmCross.Commands;
using MvvmCross.Logging;
using MvvmCross.Navigation;
using MvvmCross.ViewModels;

namespace MvvmCrossTest.Core.ViewModels
{
    public class RootViewModel: MvxNavigationViewModel
    {
        private readonly IMvxViewModelLoader _mvxViewModelLoader;
        public RootViewModel(IMvxLogProvider logProvider, IMvxNavigationService navigationService, IMvxViewModelLoader mvxViewModelLoader) : base(logProvider, navigationService)
        {
            _mvxViewModelLoader = mvxViewModelLoader;
            ShowMainMenu();
        }

        private MainMenuViewModel _mainMenuVM;

        public MainMenuViewModel MainMenuVM
        {
            get { return _mainMenuVM; }
            set 
            {
                SetProperty(ref _mainMenuVM, value);
                RaisePropertyChanged(() => MainMenuVM);
            }
        }

         public MvxCommand ShowMainMenuCommand { get; set; }

        public void ShowMainMenu()
        {
            MainMenuVM = (MainMenuViewModel)_mvxViewModelLoader.LoadViewModel(MvxViewModelRequest.GetDefaultRequest(typeof(MainMenuViewModel)), null, null);
        }
    }
}

The simplified View I want to show in the contentcontrol looks like this:

<views:MvxWpfView
    x:Class="MvvmCrossTest.Wpf.Views.MainMenuView"
    xmlns:views="clr-namespace:MvvmCross.Platforms.Wpf.Views;assembly=MvvmCross.Platforms.Wpf"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
    mc:Ignorable="d"
    Background="Aqua"
    d:DesignHeight="450" d:DesignWidth="800">
    <Grid>
            
    </Grid>
</views:MvxWpfView>

And also the corresponding ViewModel.

using MvvmCross.Logging;
using MvvmCross.Navigation;
using MvvmCross.ViewModels;

namespace MvvmCrossTest.Core.ViewModels
{
    public class MainMenuViewModel : MvxNavigationViewModel
    {
        public MainMenuViewModel(IMvxLogProvider logProvider, IMvxNavigationService navigationService) : base(logProvider, navigationService)
        {

        }
    }
}

Instead of the View/ViewModel I see a text that says "MvvmCrossTest.Core.ViewModels.MainMenuViewModel".

I don't want to use Xamarin!

解决方案

I created a project where I show you some basics.

simple

You can find the samples here.

the RootView;

<views:MvxWpfView xmlns:local="clr-namespace:SomeProject.Views" ...>
     <Grid>
           <Label Content="Hello from RootView" />
           <local:NestedView />    
     </Grid>
</views:MvxWpfView>

the NestedView;

<views:MvxWpfView ...>
     <Grid>
           <Label Content="Hello from NestedView" />  
     </Grid>
</views:MvxWpfView>

extended (custom presenter)

With this custom wpf presenter you can easily navigate to views while specified themn in a container. With that, you can close and open views from the view model while using the mvvmcross navigation service.

I copied this from another project. You can find the whole implementation in my sample project here.

the RootView;

<views:MvxWpfView ...>
      <Grid>
           <Label Content="Hello" />
           <ItemsControl region:MvxContainer.Id="RootViewRegion"/>    
      </Grid>
</views:MvxWpfView>

the RootView code behind;

[MvxContentPagePresentation(WrapInNavigationPage = true, NoHistory = false)]
public partial class RootView: MvxWpfView<RootViewModel>
{
     public RootView()
     {
          InitializeComponent();
     }
}

the RootViewModel;

public class RootViewModel: MvxNavigationViewModel
{
      private readonly IMvxNavigationService _navigationService;

      public IMvxAsyncCommand ShowNestedViewModelCommand { get; protected set; }

      public RootViewModel(IMvxLogProvider logProvider, IMvxNavigationService navigationService) : base(logProvider, navigationService)
      {
            this._navigationService = navigationService;
    
            // navigate to nested view
            this.ShowNestedViewModelCommand = new MvxAsyncCommand(() => this._navigationService.Navigate<NestedViewModel>());

            ShowNestedViewModelCommand.Execute();
      }
}

the NestedView code behind;

[MvxWpfPresenter("RootViewRegion", mvxViewPosition.NewOrExsist)]
public partial class NestedView : MvxWpfView<NestedViewModel>
{
    public NestedView()
    {
        InitializeComponent();
    }
}

good to know

when you have problems with navigation and view model connection use this code behind. It loads the viewmodel for the specific view;

[MvxContentPagePresentation(WrapInNavigationPage = true, NoHistory = false)]
public partial class SomeView : MvxWpfView<ViewModels.SomeViewModel>
{
    public SomeView()
    {
         InitializeComponent();
    
         if (!(ViewModel is ViewModels.SomeViewModel))
         {
              if (Mvx.IoCProvider.TryResolve<ViewModels.SomeViewModel>(out var someViewModel))
              {
                   ViewModel = someViewModel;
                   return;
              }
    
              var _viewModelLoader = Mvx.IoCProvider.Resolve<IMvxViewModelLoader>();
              var request = new MvxViewModelInstanceRequest(typeof(ViewModels.SomeViewModel));
              request.ViewModelInstance = _viewModelLoader.LoadViewModel(request, null);
              ViewModel = request.ViewModelInstance as ViewModels.SomeViewModel;
    
              Mvx.IoCProvider.RegisterSingleton<ViewModels.SomeViewModel>(ViewModel);
         }
    }
}

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