如何将事件从存储库通过服务一直冒泡到 UI

本文关键字：一直 服务 UI 事件 存储 | 更新日期: 2023-09-27 18:32:23

我有一个使用报告事件的组件的存储库。

我想在前端显示报告的事件。

这是存储库：

public interface IXmlRepository
{
    //irrelevant stuff removed
    event EventHandler TraceEventHandler;
}
public class XmlPanelRepository : IXmlRepository
{
    public XmlPanelRepository()
    {
        public event EventHandler TraceEventHandler;
        var panelCom = new PanelCom(); // this is a COM object that connects to a device
        // when something happens in the COM object it reports it.
        panelCom.Trace += panelCom_Trace; 
    // I want to bubble the trace events up to my UI.
        TraceEventHandler += TraceEventHandler_Tracing;
    }
    private void TraceEventHandler_Tracing(object sender, EventArgs e)
    {
        // what do I do here?
    }
    void panelCom_Trace(string message)
    {
        if (TraceEventHandler!= null) TraceEventHandler.Invoke(this, new EventArgs());
    }
}

我的 UI 使用服务与存储库交互。该服务定义为：

public interface IXmlConfigurationService
{
    //irrelevant stuff removed
    event EventHandler TraceEventHandler;
}
public class XmlConfigurationService : IXmlConfigurationService
{
    public event EventHandler TraceEventHandler;
    public XmlConfigurationService(IXmlRepository configurationRepository)
    {
        _configurationRepository.TraceEventHandler += ConfigurationRepository_TraceEventHandler;
    }
    void ConfigurationRepository_TraceEventHandler(object sender, EventArgs e)
    {
        // this never gets hit.
        if (TraceEventHandler != null) TraceEventHandler.Invoke(sender, e);
    }
}

如果我可以让它工作，我想我可以按照相同的步骤来获取显示事件报告的 UI。

如何让服务报告存储库中发生的事件？

如何将事件从存储库通过服务一直冒泡到 UI

如果我理解正确，您需要完成您的活动。 这类似于可观察对象满足观察者模式中的所有侦听观察者。 但是对于这样写的事件：

public XmlPanelRepository()
    {
        public event EventHandler TraceEventHandler;
        var panelCom = new PanelCom(); // this is a COM object that connects to a device
        // when something happens in the COM object it reports it.
        panelCom.Trace += panelCom_Trace; 
    // I want to bubble the trace events up to my UI.
        TraceEventHandler += TraceEventHandler_Tracing;
    }
    private void TraceEventHandler_Tracing(object sender, EventArgs e)
    {
        if (TraceEventHandler != null)
        {
              TraceEventHandler(this, e);
        }
    }

但是，也许您应该将事件命名为TraceEventHandler以外的名称，因为您现在正在公开一个事件（通常用过去时表示）。

还值得注意的是，您可以在冒泡时更改事件参数（如果需要）。 EventHandler（TEventArgs）可以帮助解决这个问题。

你忘了使用委托...尝试这样的事情：

public interface IXmlRepository
{
   //irrelevant stuff removed
   event EventHandler TraceEventHandler;
}
public class XmlPanelRepository : IXmlRepository
{
    public delegate void EventHandler(string parameter1, string parameter2);
    public event EventHandler TraceEventHandler;
    public XmlPanelRepository()
    {
        var panelCom = new PanelCom(); // this is a COM object that connects to a device
        // when something happens in the COM object it reports it.
        panelCom.Trace += panelCom_Trace; 
    }
    void panelCom_Trace(string message)
    {
        if (EventHandler != null)
          EventHandler("Event was hit, here's the message:", message);
    }
}
public interface IXmlConfigurationService
{
    //irrelevant stuff removed
}
public class XmlConfigurationService : IXmlConfigurationService
{
    public XmlConfigurationService(IXmlRepository configurationRepository)
    {
        _configurationRepository.TraceEventHandler += ConfigurationRepository_EventHandler;
    }
    void ConfigurationRepository_EventHandler(string parameter1, string parameter2);)
    {
        // Do something with your parameters.
        Response.Write(parameter1 + parameter2);
    }
}
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