C# 3.0 Cookbook, 3rd Edition

7.7. Creating a New Exception Type

Problem

None of the built-in exceptions in the .NET Framework provide the implementation details that you require for an exception that you need to throw. You need to create your own exception class that operates seamlessly with your application, as well as other applications. Whenever an application receives this new exception, it can inform the user that a specific error occurred in a specific component. This report will greatly reduce the time required to debug the problem.

Solution

Create your own exception class. To illustrate, let's create a custom exception class, RemoteComponentException, that will inform a client application that an error has occurred in a remote server assembly.

Discussion

The exception hierarchy starts with the Exception class; from this are derived two classes: ApplicationException and SystemException. The SystemException class and any classes derived from it are reserved for the developers of the FCL. Most of the common exceptions, such as the NullReferenceException or the OverflowException, are derived from SystemException. The FCL developers created the ApplicationException class for other developers using the .NET languages to derive their own exceptions from. This partitioning allows for a clear distinction between user-defined exceptions and the built-in system exceptions. However, Microsoft now recommends deriving directly from Exception, rather than ApplicationException. Nothing actively prevents you from deriving ...