1. Chapter 13 Exception Handling: A Deeper Look

2. Things Happen

3. Terminology

4. Exception Keywords

5. Running example namespace UsingExceptions { class Program
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace UsingExceptions {
class Program
static void Main(string[] args)
int x = 10;
int y = 5;
int result;
try
result = x / y;
Console.WriteLine("The result is: {0}", result); }
catch
Console.WriteLine("An error occurred! Better check the code!");
finally
Console.WriteLine("Just proving that this code always runs.");
Console.ReadLine();
}}}

6. Catching Specific Exceptions

7. Hierarchy try { result = x / y;
Console.WriteLine("The result is: {0}", result); }
catch (System.DivideByZeroException e)
Console.WriteLine("Whoops! You tried to divide by zero!");
Console.WriteLine(e.Message);
catch (System.ArithmeticException e)

8. More Specific First try { result = x / y;
Console.WriteLine("The result is: {0}", result); }
catch (System.ArithmeticException e)
Console.WriteLine("Whoops! You tried to divide by zero!");
Console.WriteLine(e.Message);
catch (System.DivideByZeroException e)
finally
Console.WriteLine("Just proving that this code always runs.");
Console.ReadLine();

9. Exceptions are Objects
System.Exception
Constructors
Properties
Hierarchy
System.ApplicationException (non fatal exceptions)

10. Custom Exceptions

11. using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace CustomExceptions {
public class MyOwnException : Exception
public MyOwnException()
: base("Sergey is not welcomed here!") //Exception(string)
//this.HelpLink = " }
class Program
static string GetName()
string s = Console.ReadLine();
if (s.Equals("Sergey"))
throw new MyOwnException();
return s;

12. static void Main(string[] args){
string theName;
try
theName = GetName();
Console.WriteLine("Hello {0}", theName); }
catch (MyOwnException nje)
Console.WriteLine(nje.Message);
Console.WriteLine("For help, visit: {0}", nje.HelpLink);
finally
Console.WriteLine("Have a nice day!");
Console.ReadLine();

13. 13.2 Example: Divide by Zero without Exception Handling

14. Re-throwing Exceptions
class Program {
static void DoSomeMath()
int x = 10, y = 0;
int result;
try
result = x / y;
Console.WriteLine("Result is {0}", result); }
catch
Console.WriteLine("Error in DoSomeMath()");
throw new ArithmeticException();
static void Main(string[] args)
DoSomeMath();
catch (ArithmeticException e)
Console.WriteLine("Hmm, there was an error in there, be careful!");
Console.ReadLine();

16. 13.3 Example: Handling DivideByZeroExceptions and FormatExceptions

21. 13.4 .NET Exception Hierarchy

22. 13.5 finally Block

32. 13.7 Exception Properties

38. 13.8 User-Defined Exception Classes