我正在整理一个包含这些要求的插件框架:
为此,我创建了一个新的AppDomain,并将插件程序集加载到此。
到目前为止我的实现工作达到了一定程度,但我相信我正在本地appDomain和新的AppDomain中创建插件实例。
首先加载时,我会收到重复的回调消息。当我多次加载/卸载时,我会将多个回调消息添加到列表中。这告诉我,我不仅远程加载插件程序集,而且还在本地加载插件程序集,因此我的“卸载”机制不能按照我的意愿运行。如果有人能告诉我哪里出错了,我将不胜感激。
我也理解我需要考虑插件的“生命周期”,但不知道在哪里实现它。
感谢。
(1)我有一个插件界面
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args
[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()
{
尝试
{
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true;
}
catch(Exception ex)
{
string message = ex.Message;
返回false;
}
}
(5)我的“ProxyLoader”将插件加载到单独的AppDomain
中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)我有一个回调插入
public event EventHandler<PluginContract.PluginEventArgs> Callback;
void OnCallback(PluginContract.PluginEventArgs e)
{
if (Callback != null)
{
Callback(this, e);
}
}
(7)调用(在加载程序集时在ProxyLoader中引用)
public void ProxyLoader_RaiseCallbackEvent(object source, PluginContract.PluginEventArgs e)
{
OnCallback(new PluginContract.PluginEventArgs(str));
}