我正在尝试将一些旧的。net Remoting IPC代码移植到WCF Named Pipes,我知道我可能在这里做了一些愚蠢的事情…
我有一个Windows服务使用ServiceHost/NetNamedPipeBinding端点。
我有一个WinForms UI连接到它与ChannelFactory/NetNamedPipeBinding。
无论Windows Server是否正在运行,在客户端执行CreateChannel
之后,ChannelFactory对象状态为Opened。如果服务没有运行,我希望它不是"已打开"。直到我尝试调用远程方法时才收到异常。检测连接是否成功的最好方法是什么?
如果服务实际上正在运行,我的代码工作得很好,但是当它不是(或连接被丢弃),我似乎无法使客户端状态从打开更改。
下面是我的服务助手代码:
public class WcfServerHelper
{
public static ServiceHost RemoteServiceHost { get; set; }
public static void Start(Type remotingType)
{
RemoteServiceHost = new ServiceHost(remotingType, new Uri[] {
new Uri("net.pipe://localhost")
});
RemoteServiceHost.AddServiceEndpoint(typeof(ICardPrinterRemoting), new NetNamedPipeBinding(), "LifeMedPrinter");
RemoteServiceHost.Open();
}
public static void Stop()
{
if (RemoteServiceHost != null && RemoteServiceHost.State == CommunicationState.Opened)
{
RemoteServiceHost.Close();
}
}
}
Windows服务:public partial class Service1 : ServiceBase
{
public Service1()
{
InitializeComponent();
}
protected override void OnStart(string[] args)
{
WcfServerHelper.Start(typeof(CardPrinterRemoting));
}
protected override void OnStop()
{
WcfServerHelper.Stop();
}
}
客户端帮助代码:
public class WcfClientHelper
{
public static ICardPrinterRemoting RemotingObject { get; set; }
public static ChannelFactory<ICardPrinterRemoting> PipeFactory { get; set; }
public static void ConnectIpc()
{
PipeFactory = new ChannelFactory<ICardPrinterRemoting>(new NetNamedPipeBinding(), new EndpointAddress("net.pipe://localhost/LifeMedPrinter"));
RemotingObject = PipeFactory.CreateChannel();
}
}
Windows UI (Service Client)代码:
private void btnConnect_Click(object sender, EventArgs e)
{
WcfClientHelper.ConnectIpc();
// The event handlers never get called, even if a successfully connection is made and then the Windows Service is stopped
WcfClientHelper.PipeFactory.Closing += PipeFactory_Closing;
WcfClientHelper.PipeFactory.Faulted += PipeFactory_Faulted;
WcfClientHelper.PipeFactory.Closed += PipeFactory_Closed;
if (WcfClientHelper.PipeFactory.State == CommunicationState.Opened)
{
LifeMedPrinterSettings lifeMedPrinterSettings = new LifeMedPrinterSettings();
lifeMedPrinterSettings.PrinterName = "Hello World";
// It always falls into this IF statement, but will blow up on this method call if the service isn't actually running:
WcfClientHelper.RemotingObject.SaveSettings(lifeMedPrinterSettings);
}
else
{
MessageBox.Show("No can-do");
}
}
当服务没有运行时,当我调用远程方法时,我收到的异常是:
System.ServiceModel.EndpointNotFoundException was unhandled
HResult=-2146233087
Message=There was no endpoint listening at net.pipe://localhost/LifeMedPrinter that could accept the message. This is often caused by an incorrect address or SOAP action. See InnerException, if present, for more details.
Source=mscorlib
StackTrace:
Server stack trace:
at System.ServiceModel.Channels.PipeConnectionInitiator.GetPipeName(Uri uri, IPipeTransportFactorySettings transportFactorySettings)
at System.ServiceModel.Channels.NamedPipeConnectionPoolRegistry.NamedPipeConnectionPool.GetPoolKey(EndpointAddress address, Uri via)
at System.ServiceModel.Channels.ConnectionPoolHelper.TakeConnection(TimeSpan timeout)
at System.ServiceModel.Channels.ConnectionPoolHelper.EstablishConnection(TimeSpan timeout)
at System.ServiceModel.Channels.ClientFramingDuplexSessionChannel.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at System.ServiceModel.Channels.ServiceChannel.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at System.ServiceModel.Channels.ServiceChannel.CallOnceManager.CallOnce(TimeSpan timeout, CallOnceManager cascade)
at System.ServiceModel.Channels.ServiceChannel.EnsureOpened(TimeSpan timeout)
at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)
Exception rethrown at [0]:
at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
at LifeMed.CardPrinter.Remoting.Interfaces.ICardPrinterRemoting.SaveSettings(LifeMedPrinterSettings printerSettings)
InnerException: System.IO.PipeException
HResult=-2146232800
Message=The pipe endpoint 'net.pipe://localhost/LifeMedPrinter' could not be found on your local machine.
ErrorCode=-2146232800
InnerException:
谢谢!
经过一番研究,我找到了一个答案,但不是我想要的。显然,查看服务是否可用的唯一方法是调用它-例如通过通用Ping方法,然后处理异常(就像我在我的问题中遇到的异常)。
所以我想这就是答案了。
我唯一的另一个问题是:国有财产的目的是什么?我希望State == Opened表示与该服务有一个打开的连接。
不管怎样,我有我的解决办法了。
谢谢!