Inheriting and extending .NET types

.NET has pre-built class libraries containing hundreds of thousands of types. Rather than creating your own completely new types, you can often get a head start by deriving from one of Microsoft’s types to inherit some or all its behavior, and then overriding or extending it.

Inheriting exceptions

As an example of inheritance, we will derive a new type of exception:

1. In the PacktLibrary project, add a new class file named PersonException.cs.
2. Modify the contents of the file to define a class named PersonException with three constructors, as shown in the following code:

   namespace Packt.Shared;
   public class PersonException : Exception
   {
     public PersonException() : base() { }
     public PersonException(string message) : base(message) { }
     public PersonException(string message, Exception innerException)
       : base(message, innerException) { }
   }
   

   Unlike ordinary methods, constructors are not inherited...