C# 0 The Complete Reference

switch

 statement. As mentioned, because enumerations are integral 

types, they are perfectly valid for use in a 

switch

.

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13

Exception Handling

A

n

exception

 is an error that occurs at runtime. Using C#’s exception handling 

subsystem, you can, in a structured and controlled manner, handle runtime errors. 

A principal advantage of exception handling is that it automates much of the error-

handling code that previously had to be entered “by hand” into any large program. For 

example, in a computer language without exception handling, error codes must be returned 

when a method fails, and these values must be checked manually each time the method is 

called. This approach is both tedious and error-prone. Exception handling streamlines error-

handling by allowing your program to define a block of code, called an 

exception handler, 

that is executed automatically when an error occurs. It is not necessary to manually check 

the success or failure of each specific operation or method call. If an error occurs, it will be 

processed by the exception handler.

Exception handling is also important because C# defines standard exceptions for common 

program errors, such as divide-by-zero or index-out-of-range. To respond to these errors, 

your program must watch for and handle these exceptions. In the final analysis, to be a 

successful C# programmer means that you are fully capable of navigating C#’s exception-

handling subsystem.