Everything Is an Object

In the .NET development you may hear that everything is an object. This is because all the types in the .NET Framework, including built-in and custom types, inherit from the System.Object class. Inheritance is a concept that is part of the object-oriented programming topic and that will be discussed later in the book. We can define it as a way for reusing and extending data types so that developers can create their hierarchy of types. System.Object provides the primary infrastructure that all .NET types must have. The .NET Framework ships with thousands of built-in data types that all derive from System.Object. But why is this class so important in the Common Type System? The answer is simple: the Common Type System ensures that all .NET types inherit from System.Object; particularly both value types and reference types inherit from System.Object. At this point an overview of value types and reference types is required, before delving into both categories.