Derived exceptions must appear before base class exceptions. : Custom Exception « Language Basics « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Language Basics
3. Custom Exception

using System; 
 
class MyException : ApplicationException { 
  public MyException() : base() { } 
  public MyException(string str) : base(str) { } 
 
  public override string ToString() { 
    return Message; 
  } 
} 
 
class MyDerivedException : MyException { 
  public MyDerivedException() : base() { } 
  public MyDerivedException(string str) : base(str) { } 
 
  public override string ToString() { 
    return Message;  
  } 
} 
 
class MainClass { 
  public static void Main() { 
    for(int x = 0; x < 3; x++) { 
      try { 
        if(x==0) 
           throw new MyException("Caught an MyException exception"); 
        else if(x==1) 
           throw new MyDerivedException("Caught an MyDerivedException exception"); 
        else 
           throw new Exception(); 
      } 
      catch (MyDerivedException exc) { 
        // catch the exception 
        Console.WriteLine(exc); 
      } 
      catch (MyException exc) { 
        // catch the exception 
        Console.WriteLine(exc); 
      } 
      catch (Exception exc) { 
        Console.WriteLine(exc); 
      } 
    } 
  } 
}

Caught an MyException exception
Caught an MyDerivedException exception
System.Exception: Exception of type 'System.Exception' was thrown.
   at MainClass.Main()