Asynchronous processing of functions and webservice calls. - The Code Project - VB.NET

Asynchronous processing of functions and webservice calls. - The Code Project - VB.NET

A project I have been working on has required the implementation of asynchronous processing, particularly for long running calls to web services, so I started to investigate the Microsoft Application Block for asynchronous processing, and reading articles on multi-threading and so on. One of the articles I came across was Roy Osherove's blog on implementing the Background Worker process from .NET 2.0 in .NET 1.1. This seemed exactly what I was after, especially once I had read the original article by Joval Löwy, except for three things. There was no mention of how to use this to call a webservice, it was only possible to pass in one argument, so for execution of more complex functions you would have to pass in the arguments as an array, or hashtable, and it was written in C# so I couldn't put it into my code, as the project is in VB.NET. Yes, I know I could reference a C# assembly or project in VB.NET, but it would be cleaner for my solution to port the entire code to VB.NET.
Background
The asynchronous call pattern has been explored many times now in .NET, and is described in detail in such articles as Creating a Simplified Asynchronous Call Pattern for Windows Forms Applications by David Hill.
Whidbey will introduce a component in the System.ComponentModel namespace called BackgroundWorker which encapsulates the complexities of asynchronous calls in a simple component which can be invoked from code, or dropped onto Form in the designer. It exposes methods and events for executing the asynchronous function, updating progress, canceling the execution, and completion of the execution.
As mentioned above, Joval Löwy and Roy Osherove have implemented a version of this class in C# for .NET v1.1, which will be sufficient for many people. I have ported in into VB.NET, and added a few tweaks to throw similar exceptions to the Whidbey version, when it is sub-classed. Then I extended it, and demonstrates how to use this to call webservices asynchronously.