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.NET Design Patterns
.NET Design Patterns

.NET Design Patterns: Learn to Apply Patterns in daily development tasks under .NET Platform to take your productivity to new heights.

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Profile Icon Praseed Pai Profile Icon Shine Xavier
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Full star icon Full star icon Full star icon Half star icon Empty star icon 3.6 (5 Ratings)
Paperback Jan 2017 314 pages 1st Edition
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Arrow left icon
Profile Icon Praseed Pai Profile Icon Shine Xavier
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€32.99
Full star icon Full star icon Full star icon Half star icon Empty star icon 3.6 (5 Ratings)
Paperback Jan 2017 314 pages 1st Edition
eBook
€8.99 €26.99
Paperback
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Renews at €18.99p/m
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.NET Design Patterns

Chapter 2. Why We Need Design Patterns?

In this chapter, we will try to understand the necessity of choosing a pattern-based approach to software development. We start with some principles of software development, that one might find useful while undertaking large projects. The working example in this chapter starts with a requirements specification and progresses toward a preliminary implementation. We will then try to iteratively improve the solution using patterns and idioms, and come up with a good design that supports a well-defined programming Interface. During this process, we will learn about some software development principles that one can adhere to, including the following:

  • SOLID principles for OOP
  • Three key uses of design patterns
  • Arlow/Nuestadt archetype patterns
  • Entity, value, and data transfer objects
  • Command pattern and factory method pattern
  • Design by contract idiom and the template method pattern
  • Facade pattern for API
  • Leveraging the .NET Reflection API for plugin architecture...

Some principles of software development

Writing quality production code consistently is not easy without some foundational principles under your belt. The purpose of this section is to whet the developer's appetite, and towards the end, some references are given for detailed study. Detailed coverage of these principles warrants a separate book on its own scale. The authors have tried to assimilate the following key principles of software development, which help one write quality code:

  • KISS: Keep it simple, stupid
  • DRY: Don't repeat yourself
  • YAGNI:You aren't gonna need it
  • Low coupling: Minimize coupling between classes
  • SOLID principles: Principles for better OOP

Note

William of Ockham framed the maxim Keep it simple, stupid (KISS). It is also called the law of parsimony. In programming terms, it can be translated as "writing code in a straightforward manner, focusing on a particular solution that solves the problem at hand".

This maxim is important because, most often, developers...

Why are patterns required?

According to the authors, the three key advantages of pattern-oriented software development that stand out are as follows:

  • A language/platform-agnostic way to communicate about software artifacts
  • A tool for refactoring initiatives (targets for refactoring)
  • Better API design

With the advent of the pattern movement, the software development community got a canonical language to communicate about software design, architecture, and implementation. Software development is a craft that has got trade-offs attached to each strategy, and there are multiple ways to develop software. The various pattern catalogs brought some conceptual unification for this cacophony in software development.

Most developers around the world today who are worth their salt can understand and speak this language. We believe you will be able to do the same by the end of the chapter. Imagine yourself stating the following about your recent implementation:

Tip

For our tax computation example, we have...

A quick foray into the .NET Reflection API

When we write non-trivial software that should go to production, it is mandatory to have the ability to load and execute modules on the fly. This is useful when you are planning to provide user defined extensions as a mechanism to add new features to the existing software. The .NET Reflection API is a nifty mechanism supported by the Microsoft Corporation to help developers to write code that can be loaded dynamically, after the base software has been written. The platform technologies, such as ASP.net, WCF,EF, and WPF, use reflection extensively:

     public class Test 
     { 
       //---- Only Property this class has  
       public int X { get; set; } 
       //----- This method will be invoked dynamically 
       public void Spit() 
       { 
         Console.WriteLine(" X is " + X); 
       } 
     } 

We will write a simple program that will instantiate the object using the new keyword, and after the object instantiation, a...

Personal income tax computation - A case study

Rather than explaining the advantages of patterns, the following example will help us to see things in action. Computation of annual income tax is a well-known problem domain across the globe. We have chosen an application domain that is well known for focusing on software development issues.

Note

The application should receive inputs regarding the demographic profile (UID, Name, Age, Sex, Location) of a citizen and the income details (Basic, DA, HRA, CESS, Deductions) to compute their tax liability. The system should have discriminants based on the demographic profile, and have a separate logic for senior citizens, juveniles, disabled people, female senior citizens, and others. By discriminant we mean that demographic parameters such as age, sex, and location should determine the category to which a person belongs and therefore apply category-specific computation for that individual. As a first iteration, we will implement logic for the...

Some principles of software development


Writing quality production code consistently is not easy without some foundational principles under your belt. The purpose of this section is to whet the developer's appetite, and towards the end, some references are given for detailed study. Detailed coverage of these principles warrants a separate book on its own scale. The authors have tried to assimilate the following key principles of software development, which help one write quality code:

  • KISS: Keep it simple, stupid
  • DRY: Don't repeat yourself
  • YAGNI:You aren't gonna need it
  • Low coupling: Minimize coupling between classes
  • SOLID principles: Principles for better OOP

Note

William of Ockham framed the maxim Keep it simple, stupid (KISS). It is also called the law of parsimony. In programming terms, it can be translated as "writing code in a straightforward manner, focusing on a particular solution that solves the problem at hand".

This maxim is important because, most often, developers fall into the trap...

Why are patterns required?


According to the authors, the three key advantages of pattern-oriented software development that stand out are as follows:

  • A language/platform-agnostic way to communicate about software artifacts
  • A tool for refactoring initiatives (targets for refactoring)
  • Better API design

With the advent of the pattern movement, the software development community got a canonical language to communicate about software design, architecture, and implementation. Software development is a craft that has got trade-offs attached to each strategy, and there are multiple ways to develop software. The various pattern catalogs brought some conceptual unification for this cacophony in software development.

Most developers around the world today who are worth their salt can understand and speak this language. We believe you will be able to do the same by the end of the chapter. Imagine yourself stating the following about your recent implementation:

Tip

For our tax computation example, we have used...

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Download code icon Download Code

Key benefits

  • • Dive into the powerful fundamentals of .NET framework for software development
  • • The code is explained piece by piece and the application of the pattern is also showcased.
  • • This fast-paced guide shows you how to implement the patterns into your existing applications

Description

Knowing about design patterns enables developers to improve their code base, promoting code reuse and making their design more robust. This book focuses on the practical aspects of programming in .NET. You will learn about some of the relevant design patterns (and their application) that are most widely used. We start with classic object-oriented programming (OOP) techniques, evaluate parallel programming and concurrency models, enhance implementations by mixing OOP and functional programming, and finally to the reactive programming model where functional programming and OOP are used in synergy to write better code. Throughout this book, we’ll show you how to deal with architecture/design techniques, GoF patterns, relevant patterns from other catalogs, functional programming, and reactive programming techniques. After reading this book, you will be able to convincingly leverage these design patterns (factory pattern, builder pattern, prototype pattern, adapter pattern, facade pattern, decorator pattern, observer pattern and so on) for your programs. You will also be able to write fluid functional code in .NET that would leverage concurrency and parallelism!

Who is this book for?

This book is for those with familiarity with .NET development who would like to take their skills to the next level and be in the driver’s seat when it comes to modern development techniques. Basic object-oriented C# programming experience and an elementary familiarity with the .NET framework library is required.

What you will learn

  • • Put patterns and pattern catalogs into the right perspective
  • • Apply patterns for software development under C#/.NET
  • • Use GoF and other patterns in real-life development scenarios
  • • Be able to enrich your design vocabulary and well articulate your
  • design thoughts
  • • Leverage object/functional programming by mixing OOP and FP
  • • Understand the reactive programming model using Rx and RxJs
  • • Writing compositional code using C# LINQ constructs
  • • Be able to implement concurrent/parallel programming techniques
  • using idioms under .NET
  • • Avoiding pitfalls when creating compositional, readable, and
  • maintainable code using imperative, functional, and reactive code.
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Length: 314 pages
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Language : English
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Table of Contents

14 Chapters
1. An Introduction to Patterns and Pattern Catalogs Chevron down icon Chevron up icon
2. Why We Need Design Patterns? Chevron down icon Chevron up icon
3. A Logging Library Chevron down icon Chevron up icon
4. Targeting Multiple Databases Chevron down icon Chevron up icon
5. Producing Tabular Reports Chevron down icon Chevron up icon
6. Plotting Mathematical Expressions Chevron down icon Chevron up icon
7. Patterns in the .NET Base Class Library Chevron down icon Chevron up icon
8. Concurrent and Parallel Programming under .NET Chevron down icon Chevron up icon
9. Functional Programming Techniques for Better State Management Chevron down icon Chevron up icon
10. Pattern Implementation Using Object/Functional Programming Chevron down icon Chevron up icon
11. What is Reactive Programming? Chevron down icon Chevron up icon
12. Reactive Programming Using .NET Rx Extensions Chevron down icon Chevron up icon
13. Reactive Programming Using RxJS Chevron down icon Chevron up icon
14. A Road Ahead Chevron down icon Chevron up icon

Customer reviews

Rating distribution
Full star icon Full star icon Full star icon Half star icon Empty star icon 3.6
(5 Ratings)
5 star 60%
4 star 0%
3 star 0%
2 star 20%
1 star 20%
Viby Abraham Jul 07, 2017
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Window to the broad world of patterns!
Amazon Verified review Amazon
DocTRex Jan 21, 2018
Full star icon Full star icon Full star icon Full star icon Full star icon 5
This book is quite informative, and I did enjoy it, however, it feels dumbed down and of lesser quality when compared to other publishers. Firstly, it follows no code style and C# naming convention (camel case method names and such). Additionally, I discovered small inconsistencies in code, which make me feel like no attention was given (ex. "{get;set;}," "{ get; set;}," and "{ get; set; }" all in the same example). Regardless, I'm happy I bought it, and I don't want to give a poor review for minor errors.
Amazon Verified review Amazon
stathis Feb 01, 2019
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Perfect book
Amazon Verified review Amazon
Sreeraj N R Sep 06, 2018
Full star icon Full star icon Empty star icon Empty star icon Empty star icon 2
Difficult to follow for a medium level user and the book is little expensive compared to available books for the same topics in the market
Amazon Verified review Amazon
Mr M Hill Feb 28, 2017
Full star icon Empty star icon Empty star icon Empty star icon Empty star icon 1
This book starts out by regurgitating multiple pages of acronyms and pattern names without actually explaining anything. There was no point to these pages. The same lack of care is found throughout the book; code is poorly formatted, variables unclearly named, and comments chewing up all the whitespace. Add to this the atrocious grammar and you've got yourself a book that struggles to convey meaning. The exact opposite of what you need when dealing with the complexities of design.
Amazon Verified review Amazon
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