C# 0 The Complete Reference

Throwing an Exception

The preceding examples have been catching exceptions generated automatically by the 

runtime system. However, it is possible to throw an exception manually by using the 

throw

statement. Its general form is shown here:

throw 

exceptOb

;

The

exceptOb

 must be an object of an exception class derived from 

Exception

.

Here is an example that illustrates the 

throw

 statement by manually throwing a 

DivideByZeroException

:

// Manually throw an exception.

using System;

class ThrowDemo {

  static void Main() {

    try {

      Console.WriteLine("Before throw.");

      throw new DivideByZeroException();

    }

    catch (DivideByZeroException) {

      Console.WriteLine("Exception caught.");

    }

    Console.WriteLine("After try/catch statement.");

  }

}

The output from the program is shown here:

Before throw.

Exception caught.

After try/catch statement.

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