prism发布订阅

延续上一节代码继续，多余部分代码进行删减。

一个地方发布消息，另一个地方接收消息。

也可以一个地方发布消息，多个地方接收消息。

主要是夸模块发送消息，进行通信的应用

业务：点击取消按钮的时候，在当前界面和主界面都弹窗口。

1.代码结构

2.MessageEvent.cs

using Prism.Events;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace WPFPrism.Event
{
    public class MessageEvent : PubSubEvent<string>//消息传递string类型
    {
        //这里是其他界面要引用的地方，删除会报错
        //例子是传递string类型的。这里还可以定义复杂的对象，进行传递
    }
}

3. MainViewModel.cs

using Prism.Commands;
using Prism.Events;
using Prism.Mvvm;
using Prism.Regions;
using Prism.Services.Dialogs;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using WPFPrism.Event;
using WPFPrism.Views;

namespace WPFPrism.ViewModels
{
    public class MainViewModel : BindableBase
    {
        private readonly IDialogService dialogService;
        private readonly IEventAggregator aggregator;

        public DelegateCommand<string> OpenCommand { get; set; }//创建命令，string用来接收参数，例如ViewA
        public MainViewModel(IDialogService dialogService,IEventAggregator aggregator)//这里点击快速操作。拿界面定义的区域Content
        {
            OpenCommand = new DelegateCommand<string>(Open);
            this.dialogService = dialogService;
            this.aggregator = aggregator;
            aggregator.GetEvent<MessageEvent>().Subscribe(SubMessage);
        }

        private void SubMessage(string obj)
        {
            MessageBox.Show($"我是主界面接收的消息：{obj}");
        }
        private void Open(string obj)
        {
            DialogParameters keys = new DialogParameters();
            keys.Add("title", "测试弹框");//主界面点击按钮把参数传递给弹框界面
            dialogService.ShowDialog(obj, keys, callback =>
              {
                  if (callback.Result == ButtonResult.OK)
                  {
                      string result = callback.Parameters.GetValue<string>("value");//接收传递过来的值
                  }
              });
        }
    }
}

4.ViewDViewModel.cs

using Prism.Commands;
using Prism.Events;
using Prism.Services.Dialogs;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using WPFPrism.Event;

namespace WPFPrism.ViewModels
{
    public class ViewDViewModel : IDialogAware
    {
        private readonly IEventAggregator aggregator;

        public DelegateCommand CancelComm { get; set; }
        public DelegateCommand OkComm { get; set; }

        public string Title { get; set; }

        public event Action<IDialogResult> RequestClose;


        public ViewDViewModel(IEventAggregator aggregator)
        {
            CancelComm = new DelegateCommand(Cancel);
            OkComm = new DelegateCommand(Ok);
            this.aggregator = aggregator;
            aggregator.GetEvent<MessageEvent>().Subscribe(SubMessage);
        }

        private void SubMessage(string obj)
        {
            MessageBox.Show($"我是当前界面接收的消息：{obj}");
            aggregator.GetEvent<MessageEvent>().Unsubscribe(SubMessage);//取消订阅，之后再点击就没有反应了
        }
        /// <summary>
        /// 确定
        /// </summary>
        private void Ok()
        {
            //RequestClose?.Invoke(new DialogResult(ButtonResult.OK));//或者返回OK
            OnDialogClosed();
        }

        /// <summary>
        /// 关闭
        /// </summary>
        private void Cancel()
        {
            //向MessageEvent发布一个 123 的消息
            aggregator.GetEvent<MessageEvent>().Publish("123111");
            //RequestClose?.Invoke(new DialogResult(ButtonResult.No));
        }

        public bool CanCloseDialog()
        {
            return true;
        }

        public void OnDialogClosed()
        {
            DialogParameters keys = new DialogParameters();
            keys.Add("value", "hello");//把值传递给主界面
            RequestClose?.Invoke(new DialogResult(ButtonResult.OK, keys));
        }

        public void OnDialogOpened(IDialogParameters parameters)
        {
            //首先进入这个
            //接收主界面传递过来的参数
            Title = parameters.GetValue<string>("title");
        }
    }
}

5.主界面

6.弹框界面

7.App.xaml.cs不变

using ModuleA;
using ModuleB;
using Prism.DryIoc;
using Prism.Ioc;
using Prism.Modularity;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;
using WPFPrism.ViewModels;
using WPFPrism.Views;

namespace WPFPrism
{
    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : PrismApplication
    {
        protected override Window CreateShell()
        {
            //通过容器去拿MainView,也是启动的地方
            return Container.Resolve<MainView>();
        }

        protected override void RegisterTypes(IContainerRegistry containerRegistry)
        {
            //依赖注入的功能，增加依赖注入要实现的内容
            //containerRegistry.RegisterForNavigation<ViewA>(); //containerRegistry.RegisterForNavigation<ViewA>("ViewA的具体名字")自定义，可以这样写;
            //containerRegistry.RegisterForNavigation<ViewB>();
            //containerRegistry.RegisterForNavigation<ViewC>();//我们依然使用C模块，C模块是当前程序的。

            //注册弹框提示的界面
            containerRegistry.RegisterDialog<ViewD, ViewDViewModel>();
        }

        protected override void ConfigureModuleCatalog(IModuleCatalog moduleCatalog)
        {
            //这里是走代码的
            //moduleCatalog.AddModule<ModuleAfile>();//加载A模块
            //moduleCatalog.AddModule<ModuleBfile>();//加载B模块
            base.ConfigureModuleCatalog(moduleCatalog);
        }
        protected override IModuleCatalog CreateModuleCatalog()
        {
            //这里是走配置的
            //return new DirectoryModuleCatalog()
            //{
            //    ModulePath = @"Modules"//这里是主程序exe同文件夹下面的Modules文件夹
            //};
            return base.CreateModuleCatalog();
        }

    }
}