如何知道是否在.NET Remoting中內部或遠程調用類方法？

Question

我有一個類需要在通過.Net遠程調用進行遠程調用時有不同的表現。如何在課堂內確定是否屬於這種情況？

class RemoteClass : MarshalByRefObject 
{ 
public void SomeMethod() 
{ 
    if (ConditionWhatINeed) //If this method was called internally/remotely 
    { 
    //Do one stuff 
    } 
    else 
    { 
    //Do another suff 
    } 
} 

Answer 1

你可能想看看RemotingServices.IsObjectOutOfContext Method。它也有你可能會覺得有用的例子。當然，因爲你將在'this'上調用服務器端的這個方法，它永遠不會被視爲遠程對象，但是如果向方法中添加一個參數，那麼該參數將在本地上下文中，如果不是遠程處理，上下文當遠程處理（PS這是一個未經驗證的假設在我的帳戶）。另一個有用的幫手可能是RemotingServices.IsTransparentProxy Method。

Answer 2

可能會使用System.Runtime.Remoting層次結構下的*Services對象之一，如mtijn所示。但是，您的對象模型中存在深層問題。對物體承擔雙重責任是不好的做法，難以保持和難以理解。爲什麼不公開一個專用的'遠程'對象;下面的示例演示了：

class Program 
{ 
    static void Main(string[] args) 
    { 
     InitializeRemoting(); 
     var remote = GetRemotingObject("localhost"); 
     var local = new LocalClass(); 

     remote.SomeMethod(); 
     local.SomeMethod(); 

     Console.ReadLine(); 
    } 

    static void InitializeRemoting() 
    { 
     var c = new TcpServerChannel(9000); 
     ChannelServices.RegisterChannel(c, false); 
     WellKnownServiceTypeEntry entry = new WellKnownServiceTypeEntry 
     (
      typeof(RemoteClass), 
      "LocalClass", // Lie about the object name. 
      WellKnownObjectMode.Singleton 
     ); 

     RemotingConfiguration.RegisterWellKnownServiceType(entry); 
    } 

    static LocalClass GetRemotingObject(string serverName) 
    { 
     TcpClientChannel channel = new TcpClientChannel("tcp-client", new BinaryClientFormatterSinkProvider()); 
     ChannelServices.RegisterChannel(channel, false); 

     return (LocalClass)Activator.GetObject 
     (
      typeof(LocalClass), // Remoting will happily cast it to a type we have access to. 
      string.Format("tcp://{0}:9000/LocalClass", serverName) 
     ); 
    } 
} 

public class LocalClass : MarshalByRefObject 
{ 
    public void SomeMethod() 
    { 
     OnSomeMethod(); 
    } 

    protected virtual void OnSomeMethod() 
    { 
     // Method called locally. 
     Console.WriteLine("Local!"); 
    } 
} 

// Note that we don't need to (and probably shouldn't) expose the remoting type publicly. 
class RemoteClass : LocalClass 
{ 
    protected override void OnSomeMethod() 
    { 
     // Method called remotely. 
     Console.WriteLine("Remote!"); 
    } 
} 

// Output: 
// Remote! 
// Local! 

編輯：直接回答你的問題，即使你正在努力實現的是不好的做法，複製我的代碼，只需提供virtual bool IsLocal { get { return true; } }上的本地類並覆蓋其在遠程類上。然後，您可以在if語句中使用該屬性。

編輯：如果你的服務器和你的客戶需要共享完全相同的類的實例，你應該使用Facade Pattern。例如：

class CommonImplementation 
{ 
    public static readonly CommonImplementation Instance = new CommonImplementation(); 
    private CommonImplementation() { } 

    public void SomeMethod(string someArg, bool isServerCall) 
    { 
     if (isServerCall) 
     { 
      Console.WriteLine("Remote! {0}", someArg); 
     } 
     else 
     { 
      Console.WriteLine("Local! {0}", someArg); 
     } 
    } 
} 

// These two classes are the facade. 
public class LocalClass : MarshalByRefObject 
{ 
    public virtual void SomeMethod(string someArg) 
    { 
     CommonImplementation.Instance.SomeMethod(someArg, false); 
    } 
} 
class RemoteClass : LocalClass 
{ 
    public override void SomeMethod(string someArg) 
    { 
     CommonImplementation.Instance.SomeMethod(someArg, true); 
    } 
}