使用MvvmCross 5.x在两个ViewModel之间进行通信

Question

我是Xamarin和MvvmCross的新手，我想在AnotherViewModel的MainViewModel中调用一个方法。我真的不知道这样做的最佳方法。

我在Xamarin Chat中被告知创建一个服务，从Setup as Singleton运行它并在那里保存属性以从任何地方访问它。 另外，另一位用户告诉我，有许多方法可以在视图模型之间获取信息，但我不知道它们中的任何一种。

这就是我的工作方式。这种方式准确吗？或者我应该尝试别的吗？

谢谢！

MainViewModel.cs

using System;
using System.Threading.Tasks;
using Acr.UserDialogs;
using MvvmCross.Core.Navigation;
using MvvmCross.Core.ViewModels;
using App.Core.Services.Interfaces;

namespace App.Core.ViewModels
{
    public class MainViewModel : MvxViewModel, ITestService
    {
        #region Fields

        private readonly IMvxNavigationService _navigationService;
        private readonly IUserDialogs _userDialogs;
        private bool _isRunning;

        #endregion Fields

        #region Properties
        private string _description;
        public string Description
        {
            get { return _description; }
            set { _description = value; RaisePropertyChanged(() => Description); }
        }

        #endregion Properties

        #region Constructors

        public MainViewModel(IMvxNavigationService navigationService, IUserDialogs userDialogs)
        {
            _navigationService = navigationService;
            _userDialogs = userDialogs;
        }

        #endregion Constructors

        #region Public Methods

        // Implemented Methods
        public async Task<Boolean> UpdateDescription(String description)
        {
            Description = description;
            // Do more stuff
            return true;
        }

        #endregion Public Methods

        #region Private Methods

        private void SelectItem(Item item)
        {
            _navigationService.Navigate<AnotherViewModel, AnotherViewModelParameters>(new AnotherViewModelParameters()
            {
                SelectedItem = item,
                Service = this
            });
        }

        #endregion Private Methods
    }
}

AnotherViewModel.cs

using Acr.UserDialogs;
using MvvmCross.Core.Navigation;
using MvvmCross.Core.ViewModels;
using App.Core.Services.Interfaces;

namespace App.Core.ViewModels
{
    public class AnoterViewModel : MvxViewModel<AnotherViewModelParameters>
    {
        #region Fields

        private ITestService _testService;
        private readonly IMvxNavigationService _navigationService;
        private readonly IUserDialogs _userDialogs;

        #endregion Fields

        #region Properties

        // Class Properties
        private Item _item;
        public Item Item
        {
            get { return _item; }
            set { _item = value; RaisePropertyChanged(() => Item); }
        }

        // MVVM Commands
        public IMvxCommand UpdateDescriptionCommand { get; private set; }

        #endregion Properties

        #region Constructors

        public AnotherViewModel(IMvxNavigationService navigationService, IUserDialogs userDialogs)
        {
            _navigationService = navigationService;
            _userDialogs = userDialogs;

            UpdateDescriptionCommand = new MvxCommand(UpdateDescription);
        }

        #endregion Constructors

        #region Public Methods

        public override void Prepare(AnotherViewModelParameters parameter)
        {
            _item = parameter.SelectedItem;
            _testService = parameter.Service;
        }

        #endregion Public Methods

        #region Private Methods

        private async void UpdateDescription()
        {
            var response = await _testService.UpdateDescription(_item.Description);

            if(response)
            {
                await _navigationService.Close(this);
            }
        }

        #endregion Private Methods
    }
}

ITestService.cs

using System;
using System.Threading.Tasks;

namespace App.Core.Services.Interfaces
{
    public interface ITestService
    {
        Task<Boolean> UpdateDescription(String description);
    }
}