Partial Classes in c#

The main purpose of partial classes is to allow two (or more) programmers to work on the class at the same time. The compiler then combines the partial classes into a single class.

It is common for one of these programmers to be non-human i.e. a code generating tool.

An example of the latter is a Form class in a Visual Studio Windows Forms application. Here, a Form is split into two partial classes. The code for one of these is generated by the Visual Studio designer and reflects the controls you place on the form and their properties.

The code for the other is largely added by the (human) programmer though the designer can also add 'skeleton' code to this partial class for handling events.