依赖关系的解决 - Xamarin - Unity

Question

该项目是 Unity doc 的副本，但它引发了一个我无法理解的错误

错误是：

Unhandled Exception:

Unity.Exceptions.ResolutionFailedException: Resolution of the dependency failed, type = 'System.Object', name = 'MainPage'. Exception occurred while: Calling constructor SecondPrims.Views.MainPage(). Exception is: ResolutionFailedException - Resolution of the dependency failed, type = 'SecondPrims.ViewModels.MainPageViewModel', name = '(none)'. Exception occurred while: while resolving. Exception is: InvalidOperationException - The current type, ITextToSpeech, is an interface and cannot be constructed. Are you missing a type mapping? ----------------------------------------------- At the time of the exception, the container was: Resolving SecondPrims.ViewModels.MainPageViewModel,(none) Resolving parameter 'textToSpeech' of constructor SecondPrims.ViewModels.MainPageViewModel(ITextToSpeech textToSpeech) Resolving ITextToSpeech,(none)

----------------------------------------------- At the time of the exception, the container was: Resolving SecondPrims.Views.MainPage,MainPage (mapped from System.Object, MainPage) Resolving SecondPrims.Views.MainPage,MainPage Calling constructor SecondPrims.Views.MainPage() occurred

项目文件： http://www.mediafire.com/file/fs656jowkiy2bd9/SecondPrims.zip

Answer 1

您是否正确添加了依赖项？

containerRegistry.RegisterForNavigation<MainPage>();
containerRegistry.Register<ITextToSpeech, TextToSpeech>();

Answer 2

答案是因为在各个平台注册了ITextToSpeech接口

Prism 7 changed this behavior as it is actually an anti-pattern to rely on a secondary container. You simply need to register your TextToSpeech service in the IPlatformInitializer like:

public class iOSInitializer : IPlatformInitializer
{
    public void RegisterTypes(IContainerRegistry containerRegistry)
    {
        containerRegistry.Register<ITextToSpeech, TextToSpeech_iOS>();
    }
}