无法注册数据服务 Prism Xamarin Forms [英] Cant register Data Services Prism Xamarin Forms

问题描述

我正在尝试注册我的服务，以便我可以将参数发送到下一个 ViewModel.

I'm trying to register my Service so that I can send the parameter to the next ViewModel.

这是我的 App.Xaml.cs

This is my App.Xaml.cs

protected override void RegisterTypes(IContainerRegistry containerRegistry)
    {

        containerRegistry.RegisterForNavigation<NavigationPage>();
        containerRegistry.RegisterForNavigation<View.MainPage, MainPageViewModel>();
        containerRegistry.Register<IService, Service>();
    }

我的界面:

public interface IService
{
    Task<List<TodoItem>> DataAsync();
}

获取数据的我的服务类:

My Service class that fetches data:

public class Service
{

public List<TodoItem> TodoList { get; private set; }
HttpClient client;

    Service()
    {
        client = new HttpClient();
        client.MaxResponseContentBufferSize = 256000;
    }

        public async Task<List<TodoItem>> DataAsync()
        {

            TodoList = new List<TodoItem>();


            var uri = new Uri(string.Format(Constants.RestUrl, string.Empty));

            try
            {
                var response = await client.GetAsync(uri);
                if (response.IsSuccessStatusCode)
                {
                    var content = await response.Content.ReadAsStringAsync();
                    TodoList = JsonConvert.DeserializeObject<List<TodoItem>>(content);
                    Debug.WriteLine(content);
                }
            }
            catch (Exception ex)
            {
                Debug.WriteLine(@"ERROR {0}", ex.Message);
            }

            return TodoList;
        }
    }

我从 App.Xaml.cs 这一行收到错误:

I'm getting the error from this line im App.Xaml.cs:

containerRegistry.Register<IService, Service>();

错误信息:

错误 CS0311:类型MyApp.Services.Service"不能用作泛型类型或方法IContainerRegistryExtensions.Register(IContainerRegistry)"中的类型参数TTo".没有从MyApp.Services.Service"到MyApp.Services.IService"的隐式引用转换.(CS0311) (MyApp)

Error CS0311: The type 'MyApp.Services.Service' cannot be used as type parameter 'TTo' in the generic type or method 'IContainerRegistryExtensions.Register(IContainerRegistry)'. There is no implicit reference conversion from 'MyApp.Services.Service' to 'MyApp.Services.IService'. (CS0311) (MyApp)

推荐答案

你的 Service 类需要声明它实现了 IService

your Service class needs to declare that it implements IService

public class Service : IService

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