Chapter 13. Exception handling

If you are a Java developer, C#'s exception handling mechanism is very similar to Java's, and you will feel very comfortable. ^[1] There are, of course, new things to learn – C# has done away with checked exceptions and built in something called inner exceptions, as well as other minor improvements.

^[1] VB 6 developers will find exception handling a totally new thing to pick up when they move over to VB .NET. VB 6 has no proper exception handling mechanism, and developers rely on the ancient On Error Goto construct to handle errors.

C# has four keywords for exception handling – try, catch, finally, and throw. Notice that C# does not have the throws keyword which Java developers use when declaring methods.

I shall start with a general example of exception handling in C# just to warm up a bit. This will be followed by examples on nested try blocks and user-defined exceptions. ^[2] Then I will discuss the following topics:

^[2] User-defined exceptions are exception classes written by the developer.

• The C# exception class hierarchy;

• System.Exception class;

• inner exceptions;

• general catch block;

• catching generic exceptions.