As more and more Web Services are made available additional flexibility is needed when calling them. Applications that call Web Services may need to do so in an asynchronous (parallel) manner especially when calling multiple services or services that may take a longer amount of time to complete.

The code found in this sample demonstrates how to make synchronous and asynchronous calls to Web Services using features in .NET version 2.0. The included code demonstrates the following types of asynchronous calls:

• Callbacks
• WaitHandles
• Polling
• Asynchronous Events
• Asynchronous ASP.NET Pages

The code can be downloaded from http://www.xmlforasp.net/CodeSection.aspx?csID=119.