When is it appropriate to use C# partial classes?

c# class architecture
Asterix picture Asterix · Aug 30, 2010 · Viewed 199.6k times · Source

I was wondering if someone could give me an overview of why I would use them and what advantage I would gain in the process.

Answer

JaredPar picture JaredPar · Aug 30, 2010

The biggest use of partial classes is to make life easier for code generators / designers. Partial classes allow the generator to simply emit the code they need to emit and they do not have to deal with user edits to the file. Users are likewise free to annotate the class with new members by having a second partial class. This provides a very clean framework for separation of concerns.

A better way to look at it is to see how designers functioned before partial classes. The WinForms designer would spit out all of the code inside of a region with strongly worded comments about not modifying the code. It had to insert all sorts of heuristics to find the generated code for later processing. Now it can simply open the designer.cs file and have a high degree of confidence that it contains only code relevant to the designer.

Related questions

Select distinct using linq

I have a class list of class public class LinqTest { public int id { get; set; } public string value { get; set; } } List<LinqTest> myList = new List<LinqTest>(); myList.Add(new LinqTest() { id = 1, value = "a" }); myList.Add(new …

Read More
When to use static classes in C#

Here's what MSDN has to say under When to Use Static Classes: static class CompanyInfo { public static string GetCompanyName() { return "CompanyName"; } public static string GetCompanyAddress() { return "CompanyAddress"; } //... } Use a static class as a unit of organization for methods not associated …

Read More
'namespace' but is used like a 'type'

This is my program the class uses it is called Time2 I have the reference added to TimeTest I keep getting the Error 'Time2' is a 'namespace' but is used like a 'type' Could someone please tell me what …

Read More