What is the use of a partial class?

Question

How can a partial class be useful in coding? Can anyone explain in detail with examples?

Answer 1

The main use is to separate designer-generated code (e.g. a UI, or entities) from hand-written code; the two are mashed together at compile time, so you still just get a single class, but you don't see the designer cruft when looking at code.

It's not the only useful situation, but it's the main one I've come across.

Answer 2

A partial class is used when you want to define a class over one or more files.

Usually this is used to separate the code that generates the UI from the code that does contains the UI's logic. C# does this for example.

Sometimes when I have a huge class that cannot be broken down in other ways I used partial classes to separate groups of methods together although I do this very very rarely.

Answer 3

Partial classes are very useful in scenarios , when two or more developers are working on same class. If the Class is not partial then only one developer can be working on the class at a time. But in case of partial classes, you can create a number of files with same class name(full qualified name).

partial classes declaration goes like this..

public partial class MyFirstPartialClass
{

}

Answer 4

In addition to @Jon post: it provides you possibility to destribute same class among different files. So, for example, different developers can work on same big class, without jumping into the conflicts on any source control system.

We used it often, in case of big classes, bascially Facades, to leave dev group to "breath".

Regards.