我有一个命令对象,根据请求队列的请求进行工作.这个特定的命令将在一个子应用程序域中执行它的工作.在子应用程序中执行其工作的一部分涉及阻止ConcurrentQueue操作(例如,Add或Take).我需要能够通过请求队列传播中止信号,跨越到子应用程序域,并唤醒其中的工作线程.
因此,我认为我需要通过AppDomain边界的CancellationToken.
我尝试创建一个继承自MarshalByRefObject的类：
protected class InterAppDomainAbort : MarshalByRefObject,IAbortControl
{
public InterAppDomainAbort(CancellationToken t)
{
Token = t;
}
[SecurityPermissionAttribute(SecurityAction.Demand,Flags = SecurityPermissionFlag.Infrastructure)]
public override object InitializeLifetimeService()
{
return null;
}
public CancellationToken Token
{
get;
private set;
}
};
并将其作为参数传递给worker函数：
// cts is an instance variable which can be triggered by another thread in parent appdomain cts = new CancellationTokenSource(); InterAppDomainAbort abortFlag = new InterAppDomainAbort(cts.Token); objectInRemoteAppDomain = childDomain.CreateInstanceAndUnwrap(...); // this call will block for a long while the work is being performed. objectInRemoteAppDomain.DoWork(abortFlag);
但是当objectInRemoteAppDomain尝试访问令牌getter属性时,我仍然会收到异常：
System.Runtime.Serialization.SerializationException: Type 'System.Threading.CancellationToken' in Assembly 'mscorlib,Version=4.0.0.0,Culture=neutral,PublicKeyToken=b77a5c561934e089' is not marked as serializable.
我的问题是：如何在appdomains中传播中止/取消信号,并唤醒可能在.NET并发数据结构中阻塞的线程(支持CancellationToken参数).
解决方法
已经有一段时间,因为我看着任何交叉AppDomain的东西,所以这个代码可能有问题,我还没有意识到,但它似乎是做这个工作.根本的问题是,似乎没有办法将CancellationToken [Source]从一个AppDomain转移到另一个AppDomain.所以我创建了两个来源,主要设置为适当时取消辅助.
事实上,在这种情况下有两个单独的令牌来源当然可能是一个问题,但是我不认为你不知道缺少可序列性阻止你在两个单独的AppDomains中使用相同的一个.
关于最小错误检查,Dispose实现等的标准注意事项
// I split this into a separate interface simply to make the boundary between
// canceller and cancellee explicit,similar to CancellationTokenSource itself.
public interface ITokenSource
{
CancellationToken Token { get; }
}
public class InterAppDomainCancellable: MarshalByRefObject,ITokenSource,IDisposable
{
public InterAppDomainCancellable()
{
cts = new CancellationTokenSource();
}
public void Cancel() { cts.Cancel(); }
// Explicitly implemented to make it less tempting to call Token
// from the wrong side of the boundary.
CancellationToken ITokenSource.Token { get { return cts.Token; } }
public void Dispose() { cts.Dispose(); }
private readonly CancellationTokenSource cts;
}
// ...
// Crucial difference here is that the remotable cancellation source
// also lives in the other domain.
interAppDomainCancellable = childDomain.CreateInstanceAndUnwrap(...);
var primaryCts = new CancellationTokenSource();
// Cancel the secondary when the primary is cancelled.
primaryCts.Token.Register(() => interAppDomainCancellable.Cancel());
objectInRemoteAppDomain = childDomain.CreateInstanceAndUnwrap(...);
// DoWork expects an instance of ITokenSource.
// It can access Token because they're all in the same domain together.
objectInRemoteAppDomain.DoWork(interAppDomainCancellable);
