WPF Prism PubSubEvent（订阅）

Prism 提供了事件聚合器（Event Aggregator）来实现事件的订阅和发布，允许模块之间进行松耦合的通信。

主要作用：

• 解耦合：通过事件订阅和发布，模块之间可以实现解耦合，避免直接依赖于彼此的实现细节。

示例用法：

1. 定义事件类：

public class MessageEvent : PubSubEvent<string> { }

2. 订阅事件：

eventAggregator.GetEvent<MessageEvent>().Subscribe(OnMessageEventReceived);

3. 处理事件：

private void OnMessageEventReceived(string message)
{
    // 处理接收到的事件
}

4. 发布事件：

eventAggregator.GetEvent<MessageEvent>().Publish("Hello, Prism!");

5. 解约事件：

eventAggregator.GetEvent<MessageEvent>().Unsubscribe(OnMessageEventReceived);

示例实现如下：示例下载 PrismCore.zip

第一步、创建订阅

public class MessageEvent : PubSubEvent<string>
{
}

public partial class EventControl : UserControl
{
    public EventControl(IEventAggregator eventAggregator)
    {
        InitializeComponent();
        eventAggregator.GetEvent<MessageEvent>().Subscribe(arg =>
        {
            MessageBox.Show($"接收到消息:{arg}");
        });
    }
}

第三步：MVVM发送消息

public class MainWindowViewModel : BindableBase
{
    private readonly IEventAggregator agregator;
    private readonly IRegionManager regionManager;
    public DelegateCommand EventCommand { private set; get; }
    public MainWindowViewModel(IRegionManager _regionManager, IEventAggregator _eventAggregator)
    {
        EventCommand = new DelegateCommand(ExecuteEventCommand);
        _regionManager.RegisterViewWithRegion("EventRegion", typeof(Regions.EventControl));
        regionManager = _regionManager;
        eventAggregator= _eventAggregator;
    }
    private void ExecuteEventCommand()
    {
        eventAggregator.GetEvent<MessageEvent>().Publish("Hello, Prism!");
    }
}

<ContentControl Grid.Row="2" prism:RegionManager.RegionName="EventRegion"/>

<Button Content="发送订阅消息" Width="120" Margin="50 0">
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="Click">
            <i:InvokeCommandAction Command="{Binding EventCommand}"/>
        </i:EventTrigger>
    </i:Interaction.Triggers>
</Button>