C# 4 and .NET 4

OC226 ❘ ChaPTer 54 .net remOtinG
Take a look at an example. To see all the parts of event handling with .NET Remoting, create five classes:
Server, Client, RemoteObject, EventSink, and StatusEventArgs. The dependencies of these classes are
shown in Figure 54-5.
«serializable»
StatusEventArgs
+Message
call handler
on event
«remotable»
EvenSink
+StatusHandler()
«remotable»
RemoteObject
+LongWorking()
Client
Server
+Main()
figure 54-5
+Main()
The Server class is a remoting server such as the one you are already familiar with. The Server class
will create a channel based on information from a configuration file and register the remote object that’s
implemented in the RemoteObject class in the remoting runtime. The remote object declares the arguments
of a delegate and fires events in the registered handler functions. The argument that’s passed to the handler
function is of type StatusEventArgs. The class StatusEventArgs must be serializable so that it can be
marshaled to the client.
The Client class represents the client application. This class creates an instance of the EventSink class
and registers the StatusHandler() method of this class as a handler for the delegate in the remote object.
EventSink must be remotable like the RemoteObject class, because this class will also be called across
the network.
remote object
The remote object class is implemented in the file RemoteObject.cs. The remote object class must
be derived from MarshalByRefObject, as you already know from the previous examples. To enable
the client to register an event handler that can be called from within the remote object, you have to
declare an external function with the delegate keyword. Declare the delegate StatusEvent() with two
arguments: the sender (so the client knows about the object that fired the event) and a variable of type
StatusEventArgs. Into the argument class you can put all the additional information that you want to send
to the client.
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