Hi Dwight,

This example (in the DDL) defines two services HelloWorldService and
HelloWorldClient. When a message arrives at the queue corresponding to
HelloWorldService (that's ServiceQueue in the DDL) the stored procedure that
corresponds to the .NET method ServiceProc in the HelloWorldService.cs or
HelloWorldService.vb code. So its HelloWorldService's static method
ServiceProc() that is being called.

The first thing ServiceProc does is to create an instance of the
HelloWorldService class. Then it calls the HelloWorldService's Run method.
This method is available because HelloWorldService inherits from the class
Microsoft.Samples.SqlServer.Service class. The code for this class can be
found in the examples directory "ServiceBrokerInterface".

The Run method reads a message from the queue when one is available and
dispatches the message (in the DispatchMessage method using Invoke) to the
method in the HelloWorldService class derived class ("your" class) that
contains the attribute (.NET attribute) named BrokerMethod. The BrokerMethod
attribute "names" a message and message contract (in this case, "Request"
message and "Greeting" contract).

Put a little bit more simply, when a message arrives, a dispatcher in the
base class looks at an array of contract, message, method names and
dispatches the message to one method name that matches contract and message.
So that's how "SayHello" is called.

The thing that makes the sample non-intuitive is that the attribute
[BrokerMethod("Greeting", "Request")] in the code is pretty well hidden
because of the gratuitous SuppressMessage attributes. Scroll to the right on
the line with SuppressMessage to see the most important attribute on the
line!!

Hope this helps, write back if it doesn't,
Bob Beauchemin
SQLskills