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我正在整理一个具有这些要求的插件框架：

  • 随意加载/卸载插件
  • 在加载的插件中调用方法
  • 从插件向所有者提出回调事件

为此，我正在创建一个新的 AppDomain，并将插件程序集加载到其中。

到目前为止，我的实现在一定程度上是有效的，但我相信我正在本地 appDomain 以及新的 AppDomain 中创建插件的实例。

当我第一次加载时，我收到重复的回调消息。当我多次加载/卸载时，我将多个回调消息添加到列表中。这表明我不仅要远程加载插件程序集，还要在本地加载插件程序集，因此我的“卸载”机制没有按照我的意愿运行。如果有人能告诉我哪里出错了，我将不胜感激。

我也知道我需要考虑插件的“生命周期”，但不确定在哪里实现。

谢谢。

(1)我有一个插件接口

public interface IPlugin
{
    string Name();
    string Version();
    string RunProcess();

    // custom event handler to be implemented, event arguments defined in child class
    event EventHandler<PluginEventArgs> CallbackEvent;
    //event EventHandler<EventArgs> CallbackEvent;
    void OnProcessStart(PluginEventArgs data);
    void OnProcessEnd(PluginEventArgs data);
}

(2) 自定义事件参数

[Serializable]
public class PluginEventArgs : EventArgs
{
    public string ResultMessage;
    public string executingDomain;

    public PluginEventArgs(string resultMessage = "")
    {
        // default empty values allows us to send back default event response
        this.ResultMessage = resultMessage;
        this.executingDomain = AppDomain.CurrentDomain.FriendlyName;
    }
}

(3) 示例插件类实现

 [Serializable]
    public class Plugin_1 : IPlugin
    {
        System.Timers.Timer counter;
        int TimerInterval;
        string PluginName = "My plugin";

        public string Name()
        {
            return "CMD";
        }

        public bool Start()
        {
            OnStart(new PluginEventArgs());
            RunProcess();
            return true;
        }

        // OnTimer event, process start raised, sleep to simulate doing some work, then process end raised
        public void OnCounterElapsed(Object sender, EventArgs e)
        {
            OnProcessStart(new PluginEventArgs());
            OnProcessEnd(new PluginEventArgs());
            Stop();
        }

        public bool Stop()
        {
            // simulate waiting for process to finish whatever its doing....
            if (counter != null)
            {
                counter.Stop();
                OnStop(new PluginEventArgs());
            }
            return true;
        }

        public string RunProcess()
        {
            TimerInterval = 2000;
            if (counter == null){ 
                counter = new System.Timers.Timer(TimerInterval); 
                }
            else { 
                counter.Stop();
                counter.Interval = TimerInterval;
                }

            counter.Elapsed += OnCounterElapsed;
            counter.Start();
            return "";
        }

        public event EventHandler<PluginEventArgs> CallbackEvent;

        void OnCallback(PluginEventArgs e)
        {
            if (CallbackEvent != null)
            {
                CallbackEvent(this, e);
            }                    
        }


        public void OnProcessStart(PluginEventArgs Data)
        {
            OnCallback(new PluginEventArgs(Data.executingDomain + " - " + PluginName + " started"));   
        }

        public void OnProcessEnd(PluginEventArgs Data)
        {
            OnCallback(new PluginEventArgs(Data.executingDomain + " - " + PluginName + " ended"));   
        }

(4) 我有一个加载/卸载的插件管理器

public bool LoadPlugin() { try { Domain_Command = AppDomain.CreateDomain("Second_domain"); command_loader = (ProxyLoader)Domain_Command.CreateInstanceAndUnwrap("PluginMgr", "PluginMgr.Method"); Plugins.AddPlugin(command_loader.LoadAndExecute("APluginName", Plugins.ProxyLoader_RaiseCallbackEvent), SomePluginType, false);
返回真；
} catch (Exception ex) { string message = ex.Message; 返回假；} }

(5) 我的“ProxyLoader”将插件加载到单独的AppDomain

public class ProxyLoader : MarshalByRefObject
{
    public AssemblyInstanceInfo LoadAndExecute(string assemblyName, EventHandler<PluginContract.PluginEventArgs> proxyLoader_RaiseCallbackEvent)
    {
        AssemblyInstanceInfo AInfo = new AssemblyInstanceInfo();
        //nb: this AppDomain.CurrentDomain is in its own context / different from the caller app domain?
        Assembly pluginAssembly = AppDomain.CurrentDomain.Load(assemblyName);
        foreach (Type type in pluginAssembly.GetTypes())
        {
            if (type.GetInterface("IPlugin") != null)
            {
                object instance = Activator.CreateInstance(type, null, null);
                AInfo.ObjectInstance = instance;
                string s = ((PluginContract.IPlugin)instance).RunProcess(); // main procedure
                AInfo.ASM = pluginAssembly;
                ((PluginContract.IPlugin)instance).CallbackEvent += proxyLoader_RaiseCallbackEvent;
                ((PluginContract.IPlugin)instance).Start();
                instance = null;
            }
        }
        return AInfo;
    }
}

(6) 我有一个回调这个插件

public event EventHandler<PluginContract.PluginEventArgs> Callback;

void OnCallback(PluginContract.PluginEventArgs e)
        {
            if (Callback != null)
            {
                Callback(this, e);
            }
        }

(7)由（加载程序集时在ProxyLoader中引用）调用

public void ProxyLoader_RaiseCallbackEvent(object source, PluginContract.PluginEventArgs e)
{
    OnCallback(new PluginContract.PluginEventArgs(str));
}
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0 回答 0