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

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.