Learning C#

Exception Class Methods and Properties

So far you’ve been using the exception as a sentinel — that is, the presence of the exception signals the errors — but you haven’t touched or examined the Exception object itself. The System.Exception class provides a number of useful methods and properties.

The Message property provides information about the exception, such as why it was thrown. The Message property is read-only; the code throwing the exception can pass in the message as an argument to the exception constructor, but the Message property cannot be modified by any method once set in the constructor.

The HelpLink property provides a link to a help file associated with the exception. This property is read/write. In Example 18-6, the Exception.HelpLink property is set and retrieved to provide information to the user about the DivideByZeroException. It is generally a good idea to provide a help file link for any exceptions you create, so that the user can learn how to correct the exceptional circumstance.

The read-only StackTrace property is set by the CLR. This property is used to provide a stack trace for the error statement. A stack trace is used to display the call stack: the series of method calls that lead to the method in which the exception was thrown.

Example 18-6. Inside the Exception class

using System; namespace ExceptionHandling { class Tester { public void Run() { try { Console.WriteLine("Open file here"); double a = 12; double b = 0; Console.WriteLine ("{0} ...