Returning a custom exception

Question

I am trying to implement my own Exception class in C#. For this purpose I have created a CustomException class derived from Exception.

class CustomException : Exception {     public CustomException()         : base() { }      public CustomException(string message)         : base(message) { }      public CustomException(string format, params object[] args)         : base(string.Format(format, args)) { }      public CustomException(string message, Exception innerException)         : base(message, innerException) { }      public CustomException(string format, Exception innerException, params object[] args)         : base(string.Format(format, args), innerException) { } } 

Then I use it

static void Main(string[] args) {     try     {         var zero = 0;         var s = 2 / zero;     }     catch (CustomException ex)     {         Console.Write("Exception");         Console.ReadKey();     } } 

I'm expecting I will get my exception but all I get is a standard DivideByZeroException. How can I catch a divide by zero exception using my CustomException class? Thanks.

Answer 1

You can't magically change type of exception thrown by existing code.

You need to throw your exception to be able to catch it:

try  {    try     {         var zero = 0;         var s = 2 / zero;     }     catch (DivideByZeroException ex)     {          // catch and convert exception         throw new CustomException("Divide by Zero!!!!");     } } catch (CustomException ex) {     Console.Write("Exception");     Console.ReadKey(); } 

Answer 2

First of all, if you want to see your own exception, you should throw it somewhere in your code:

public static int DivideBy(this int x, int y) {     if (y == 0)     {         throw new CustomException("divide by zero");     }     return x/y;   } 

then:

int a = 5; int b = 0; try {       a.DivideBy(b); } catch(CustomException) { //.... }