COM Clients Without Notifying Your Code Your Code

摘要

Many developers who still use ASP pages for presentation services are integrating COM and .NET objects to provide the business services of the application. Using .NET objects from ASP can help developers gain experience with the .NET Framework before migrating to ASP.NET. Their ASP pages make use of the new .NET components through COM-callable wrappers (CCW). But how do they handle exceptions? Whenever a .NET exception is thrown from .NET components to the ASP page, it's converted into an Err object that contains information on the error. Unfortunately, a wealth of information such as the stack trace, all inner exceptions, and other properties within the .NET exception are lost; only the string description and a number are returned to the ASP page. To allow .NET exceptions thrown to COM clients to be added to the event log, I've written a component that uses techniques such as hooking.