C# 0 The Complete Reference

DivideByZeroException

exception is generated. As you will see later in this chapter, you can create your own 

exception classes by deriving them from 

Exception

.

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P a r t   I :  

T h e   C #   L a n g u a g e

Exception Handling Fundamentals

C# exception handling is managed via four keywords: 

try

,

catch

,

throw

, and 

finally

.

They form an interrelated subsystem in which the use of one implies the use of another. 

Throughout the course of this chapter, each keyword is examined in detail. However, it 

is useful at the outset to have a general understanding of the role each plays in exception 

handling. Briefly, here is how they work.

Program statements that you want to monitor for exceptions are contained within a 

try

 block. If an exception occurs within the 

try

 block, it is 

thrown.

 Your code can catch this 

exception using 

catch

 and handle it in some rational manner. System-generated exceptions 

are automatically thrown by the runtime system. To manually throw an exception, use the 

keyword 

throw

. Any code that absolutely must be executed upon exiting from a