Refactoring code in .net

About me • Nguyen Thanh Tung • Software architect at MISA JSC • Microsoft Certified Professional Developer • Technologies: • Windows/Windows Phone • ASP.NET • XAML/Silverlight • Windows Forms • … • Blog at: http://tungnt.net • Facebook Page: https://www.facebook.com/tungnt185 • Meetup group: http://www.meetup.com/Ha-Noi-NET-Meetup/

http://tungnt.net Table of contents • Refactoring General – What is refactoring? – Who will refactor code? – Why we need refactor code? – When to refactor code? – Where to refactor code? • How to refactor code?

http://tungnt.net What is refactoring? Refactoring means "to improve the design and quality of existing source code without changing its external behavior". Martin Fowler Bad Code Good CodeRefactoring

http://tungnt.net Who will refactor code? • You - Developers

http://tungnt.net Why we need refactor code? • Code constantly changes and its quality constantly degrades (unless refactored) • Requirements often change and code needs to be changed to follow them

http://tungnt.net When to refactor code? • Bad smells in the code indicate need of refactoring • Refactor when you – Add a new method or class – Fix an existing bug – Reviewing someone else’s code – Implement TDD (Test-Driven-Development) • Unit tests guarantee that refactoring does not change the behavior – If there are no unit tests, write them

http://tungnt.net Where to refactor code? • Code smells - certain code structures have possibility of refactoring • Types of code smells: • Duplicated code • Long method • Large class • Long parameter list • Switch statements • Improper naming • Data members are public • …

http://tungnt.net Naming • Should be proper, descriptive and consistent for readability and maintainability

http://tungnt.net Duplicated code • Violates the DRY (Don’t repeat yourself) principle • Result of copy-pasted code • Solutions: Extract method, extract class, pull-up method for maintainability

http://tungnt.net Long Method Extract method to small methods are always better (easy naming, understanding, less duplicate code)

http://tungnt.net Conditional complexity • Extract method

http://tungnt.net Loosely Couple Code • Extract Interface, Extract factory for extensibility

http://tungnt.net Return value instead of exception • Increase performance and readability

http://tungnt.net Switch statement • Can be replaced with polymorphism for extensibility

http://tungnt.net Remove multiple if • Return ASAP (as soon as possible) For readability

http://tungnt.net Parameter object • For readability and extensibility

http://tungnt.net References • “Refactoring: Improving the Quality of Existing Code“ by Telerik Academy • 31 days of refactoring - lostechies.com

Refactoring code in .net

More Related Content

What's hot

Viewers also liked

Similar to Refactoring code in .net

More from Tung Nguyen Thanh

Recently uploaded

Refactoring code in .net