棱镜如何找到视图文件夹的子文件夹中的视图

Question

我正在学习windows store应用程序中的棱镜。我遇到了问题。我有很多意见，我想将它们分成不同的文件夹。但问题在于NavigationService无法找到它们。说明书说，所有视图显示放入视图文件夹，然后导航服务可以使用navigationservice.navigate（“main”，null）导航到它们，但是如果视图不在导航服务找不到它们的视图文件夹的根目录

Answer 1

NavigationService根据约定查找Views和ViewModels。所有视图必须位于“视图”文件夹中，并且ViewModels必须位于“ViewModels”文件夹中。如果ID不适合你可以做到以下几点：

1. 添加下面的类到你的项目：

   public class ViewViewModelTypeResolver 
   { 
       private const string ViewNameSuffix = "Page"; // You can change this View name suffix 
       private const string ViewModelNameSuffix = "ViewModel"; // You can change this ViewModel name suffix 
   
       private readonly Lazy<Dictionary<string, Type>> _uiAssemblyExportedTypes; 
   
       private Dictionary<string, Type> UiAssemblyExportedTypes 
       { 
        get { return _uiAssemblyExportedTypes.Value; } 
       } 
   
       public ViewViewModelTypeResolver(Type typeFromUiAssembly) 
       { 
        _uiAssemblyExportedTypes = new Lazy<Dictionary<string, Type>>(() => GetUiAssemblyExportedTypes(typeFromUiAssembly)); 
       } 
   
       public Type GetViewType(string viewTypeName) 
       { 
        return UiAssemblyExportedTypes[viewTypeName]; 
       } 
   
       public Type GetViewModelType(Type viewType) 
       { 
        var pageNameWithoutSuffix = viewType.Name.Remove(viewType.Name.LastIndexOf(ViewNameSuffix, StringComparison.Ordinal)); 
        var viewModelName = String.Concat(pageNameWithoutSuffix, ViewModelNameSuffix); 
        return UiAssemblyExportedTypes[viewModelName]; 
       } 
   
   
       private static Dictionary<string, Type> GetUiAssemblyExportedTypes(Type typeFromUiAssembly) 
       { 
        return typeFromUiAssembly.GetTypeInfo().Assembly.ExportedTypes.ToDictionary(type => type.Name, type => type, StringComparer.Ordinal); 
       } 
   } 
   

2. 添加ViewViewModelTypeResolver到App构造函数：

   public App() 
   { 
       var mainPage = typeof(MainPage); // Any of pages from your solution. Pay attention that the resolver will be able to resolve Views and ViewModels that locates in the same project as specified page. 
       _viewViewModelTypeResolver = new ViewViewModelTypeResolver(mainPage); 
   } 
   

3. 当你使用Prism时，我假设你从MvvmAppBase继承你的App类。如果是这样，你应该重写GetPageType方法：

   protected override Type GetPageType(string pageToken) 
       { 
        return _viewViewModelTypeResolver.GetViewType(pageToken); 
       } 
   

4. 然后在OnInitializeAsync方法添加SetDefaultViewTypeToViewModelTypeResolver：

   protected override async Task OnInitializeAsync(IActivatedEventArgs args) 
   { 
       // Your initialization code 
   
       ViewModelLocationProvider.SetDefaultViewTypeToViewModelTypeResolver(GetViewModelType); 
   
       // Your initialization code 
   } 
   
   private Type GetViewModelType(Type pageType) 
   { 
       return _viewViewModelTypeResolver.GetViewModelType(pageType); 
   } 
   

现在你可以浏览到任何网页上，即使它们被分成不同的文件夹。

Answer 2

来自Alexander.Ermolaev的很好回答。我想扩展他的课程以满足我的需求。我不喜欢公开所有的ViewModel。当我们真正需要的是Views和ViewModels的类型时，我也不想保留所有类型的字典。这将查找从UserControl继承的所有视图，因为ViewModelLocator将与UserControl以及Pages一起使用。这将找到所有从基本视图模型类继承的ViewModel，通常是Prism的ViewModelBase。从App.cs

sealed class ViewViewModelTypeResolver 
{ 
    private readonly Assembly _assembly; 
    private readonly Type _baseViewModelType; 
    private readonly string _viewNameSuffix; 
    private readonly string _viewModelNameSuffix; 
    private readonly Lazy<Dictionary<string, Type>> _views; 
    private readonly Lazy<Dictionary<string, Type>> _viewModels; 

    private Dictionary<string, Type> Views => _views.Value; 
    private Dictionary<string, Type> ViewModels => _viewModels.Value; 

    /// <summary> 
    /// Resolves Views and ViewModels. 
    /// </summary> 
    /// <param name="typeFromUiAssembly">Use any type from the UI Assembly.</param> 
    /// <param name="baseViewModelType">All view models need to inherit from this type.</param> 
    /// <param name="viewNameSuffix">Prism convention is to name your views with a Page suffix.</param> 
    /// <param name="viewModelNameSuffix">Prism convention is name your viewmodels with a ViewModel suffix.</param> 
    public ViewViewModelTypeResolver(Type typeFromUiAssembly, Type baseViewModelType, string viewNameSuffix = "Page", string viewModelNameSuffix = "ViewModel") 
    { 
     _baseViewModelType = baseViewModelType; 
     _viewNameSuffix = viewNameSuffix; 
     _viewModelNameSuffix = viewModelNameSuffix; 
     _assembly = typeFromUiAssembly.GetTypeInfo().Assembly; 

     _views = new Lazy<Dictionary<string, Type>>(GetViews); 
     _viewModels = new Lazy<Dictionary<string, Type>>(GetViewModels); 
    } 

    /// <summary> 
    /// Gets a View type for the given name. 
    /// </summary> 
    /// <param name="viewTypeName">Name of the view without the suffix.</param> 
    public Type GetViewType(string viewTypeName) 
    { 
     var pageName = string.Concat(viewTypeName, _viewNameSuffix); 
     return this.Views[pageName]; 
    } 

    /// <summary> 
    /// Gets a ViewModel for the given view type. 
    /// </summary> 
    /// <param name="viewType">Type of view.</param> 
    public Type GetViewModelType(Type viewType) 
    { 
     var viewModelName = string.Concat(viewType.Name, _viewModelNameSuffix); 
     return this.ViewModels[viewModelName]; 
    } 

    /// <summary> 
    /// Gets all the View types by finding all types that inherit from Page and are defined in the UI Assembly. 
    /// </summary> 
    private Dictionary<string, Type> GetViews() 
    { 
     var types = _assembly.DefinedTypes.Where(type => !type.IsAbstract && type.IsSubclassOf(typeof(UserControl))); 

     return types.ToDictionary(typeInfo => typeInfo.Name, typeInfo => typeInfo.AsType(), StringComparer.Ordinal); 
    } 

    /// <summary> 
    /// Gets all the ViewModel types by finding all types that inherit from a base ViewModel type defined in the UI Assembly. 
    /// </summary> 
    private Dictionary<string, Type> GetViewModels() 
    { 
     var types = _assembly.DefinedTypes.Where(type => !type.IsAbstract && type.IsSubclassOf(_baseViewModelType)); 

     return types.ToDictionary(typeInfo => typeInfo.Name, typeInfo => typeInfo.AsType(), StringComparer.Ordinal); 
    } 
} 

用法：

private readonly ViewViewModelTypeResolver _viewViewModelTypeResolver; 

public App() 
{ 
    this.InitializeComponent(); 

    _viewViewModelTypeResolver = new ViewViewModelTypeResolver(this.GetType(), typeof(ViewModelBase)); 
} 

//other methods are the same as Alexander's answer. 

感谢亚历山大，你的代码对我来说是很好的起点。