A partial class, or partial type, is a class that can be split into two or more source code files and/or two or more locations within the same source file. Each partial class is known as a class part or just a part. Logically, partial classes do not make any difference to the compiler. The compiler puts the class together at compile time and treats the final class or type as a single entity exactly the same as if all the source code was in a single location.

Languages Focus

For languages that have implemented partial classes, you need to know usage details and restrictions. Can you split a class into two or more files? Can you split a class within a source code file into two or more locations? What are the details of inheritance? Does it apply to interfaces as well?

C#:  "Partial Classes" partial C# uses the keyword partial to specify a partial class. All parts must be in the same namespace. Syntax Example: class partial Cyborg: System.Object { }  C# Partial Classes (partial)

Cross Reference Examples:

Access VBA:  "Partial Classes" Not Supported	ASP Classic:  "Partial Classes" Not Supported
C++:  "Partial Classes" Not Supported In C++, you can split the implementation of a class among two or more source files. However, you must declare the member in the class declaration.	C++/CLI:  "Partial Classes" Not Supported C++/CLI does not yet support partial classes. My assumption is that it will soon because it is a .Net language�but only time will tell.
Corel Paradox:  "Partial Classes" Not Supported	Delphi:  "Partial Classes" Not Supported As of Delphi 2009, partial classes are not supported. The main reason given in the thread below was that the Delphi compiler is a single pass compiler. Here is a link to a discussion thread on the subject: Delphi language (partial classes)
Delphi Prism:  "Partial Classes" partial Prism supports both partial classes and partial methods using the keyword partial. A partial method is an empty method defined in a partial class. Syntax Example: //Organize a large class in multiple files. T800 = partial class(Cyborg, IHuman); end; T800 = partial class(ITalk); end; //Partial methods too:� T800 = public partial class private method Walk; partial; empty; method Run; partial; empty; end;  Delphi Prism Partial Classes (partial)	Java:  "Partial Classes" Not Supported
VB Classic:  "Partial Classes" Not Supported	VB.Net:  "Partial Classes" Partial VB.Net supports both partial classes and partial methods. Syntax Example: Partial Public Class Cyborg Inherits System.Object End Class  VB.Net Partial Classes (Partial)