The CTS and CLS

Having seen the importance of metadata and IL, let’s examine the CTS and the CLS. Both the CTS and the CLS ensure language compatibility, interoperability, and integration.

The Common Type System (CTS)

Because .NET treats all languages as equal, a class written in C# should be equivalent to a class written in VB.NET, and an interface defined in Managed C++ should be exactly the same as one that is specified in managed COBOL. Languages must agree on the meanings of these concepts before they can integrate with one another. In order to make language integration a reality, Microsoft has specified a common type system to which every .NET language must abide. In this section, we outline the common types that have the same conceptual semantics in every .NET language. Microsoft .NET supports a rich set of types, but we limit our discussion to the important ones, including value types, reference types, classes, interfaces, and delegates.

Value types

In general, the CLR supports two different types: value types and reference types. Value types represent values allocated on the stack. They cannot be null and must always contain some data. When value types are passed into a function, they are passed by value, meaning that a copy of the value is made prior to function execution. This implies that the original value won’t change, no matter what happens to the copy during the function call. Since intrinsic types are small in size and don’t consume much memory, the resource cost ...

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