public MarshalByValType MethodWithReturn() { Console.WriteLine("Executing in " + Thread.GetDomain().FriendlyName); MarshalByValType t = new MarshalByValType(); return(t); }
private static void Marshalling() { AppDomain adCallingThreadDomain = Thread.GetDomain(); String callingDomainName = adCallingThreadDomain.FriendlyName; Console.WriteLine("Default AppDomain’s friendly name={0}", callingDomainName); String exeAssembly = Assembly.GetEntryAssembly().FullName; Console.WriteLine("Main assembly={0}", exeAssembly); AppDomain ad2 = null; // *** DEMO 1: Cross-AppDomain Communication using Marshal-by-Reference *** Console.WriteLine("{0}Demo #1", Environment.NewLine); // Create new AppDomain (security & configuration match current AppDomain) ad2 = AppDomain.CreateDomain("AD #2", null, null); MarshalByRefType mbrt = null; // Load our assembly into the new AppDomain, construct an object, marshal // it back to our AD (we really get a reference to a proxy) mbrt = (MarshalByRefType)ad2.CreateInstanceAndUnwrap(exeAssembly, "AppDomains.MarshalByRefType"); Console.WriteLine("Type={0}", mbrt.GetType()); // The CLR lies about the type // Prove that we got a reference to a proxy object Console.WriteLine("Is proxy={0}", RemotingServices.IsTransparentProxy(mbrt)); // This looks like we’re calling a method on MarshalByRefType but, we’re not. // We’re calling a method on the proxy type. The proxy transitions the thread // to the AppDomain owning the object and calls this method on the real object. mbrt.SomeMethod(); // Unload the new AppDomain AppDomain.Unload(ad2); // mbrt refers to a valid proxy object; the proxy object refers to an invalid AppDomain try { // We’re calling a method on the proxy type. The AD is invalid, exception is thrown mbrt.SomeMethod(); Console.WriteLine("Successful call."); } catch (AppDomainUnloadedException) { Console.WriteLine("Failed call."); } // *** DEMO 2: Cross-AppDomain Communication using Marshal-by-Value *** Console.WriteLine("{0}Demo #2", Environment.NewLine); // Create new AppDomain (security & configuration match current AppDomain) ad2 = AppDomain.CreateDomain("AD #2", null, null); // Load our assembly into the new AppDomain, construct an object, marshal // it back to our AD (we really get a reference to a proxy) mbrt = (MarshalByRefType)ad2.CreateInstanceAndUnwrap(exeAssembly, "AppDomains.MarshalByRefType"); // The object’s method returns a COPY of the returned object; // the object is marshaled by value (not be reference). MarshalByValType mbvt = mbrt.MethodWithReturn(); // Prove that we did NOT get a reference to a proxy object Console.WriteLine("Is proxy={0}", RemotingServices.IsTransparentProxy(mbvt)); // This looks like we’re calling a method on MarshalByValType and we are. Console.WriteLine("Returned object created " + mbvt.ToString()); // Unload the new AppDomain AppDomain.Unload(ad2); // mbvt refers to valid object; unloading the AppDomain has no impact. try { // We’re calling a method on an object; no exception is thrown Console.WriteLine("Returned object created " + mbvt.ToString()); Console.WriteLine("Successful call."); } catch (AppDomainUnloadedException) { Console.WriteLine("Failed call."); } // DEMO 3: Cross-AppDomain Communication using non-marshalable type *** Console.WriteLine("{0}Demo #3", Environment.NewLine); // Create new AppDomain (security & configuration match current AppDomain) ad2 = AppDomain.CreateDomain("AD #2", null, null); // Load our assembly into the new AppDomain, construct an object, marshal // it back to our AD (we really get a reference to a proxy) mbrt = (MarshalByRefType) ad2.CreateInstanceAndUnwrap(exeAssembly, "AppDomains.MarshalByRefType"); // The object’s method returns an non-marshalable object; exception NonMarshalableType nmt = mbrt.MethodArgAndReturn(callingDomainName); // We won’t get here... }