LINQ to Objects Using C# 4.0 Using and Extending LINQ to Objects and Parallel LINQ (PLINQ)

by Magennis, Troy

• ISBN13: 9780321637000
• ISBN10: 0321637003
• Edition: 1st
• Format: Paperback
• Copyright: 2010-03-02
• Publisher: Addison-Wesley Professional

Summary

TheOnlyComplete, Realistic, Example-Rich Guide toLINQ to Objects, PLINQ, and C# 4.0 Using LINQ to Objects, .NET developers can write queries over object collections with the same deep functionality that was once available only with SQL and relational databases. Now, for the first time, developers have a comprehensive and authoritative guide to applying LINQ to Objects in real-world software. Microsoft MVP Troy Magennis introduces state-of-the-art techniques for working with objects more elegantly and efficientlyand writing code that is exceptionally powerful, robust, and flexible. Drawing on his unsurpassed experience coding LINQ software and hosting the popular HookedonLINQ.com site, Magennis presents timely, realistic solutions to a wide spectrum of development challenges. Yours"ll begin with five-minute quick-starts that walk you through LINQ to Objectsrs" key features. Next, yours"ll drill down to detailed techniques for applying these features with C# 4.0 and C# 3.0including code examples that reflect the realities of production development. Coverage includes: Writing basic LINQ queries with C#: filtering, projecting, and sequencing data from in-memory collections Mastering advanced techniques for grouping and joining data Taking full advantage of LINQrs"s standard query and set-based operators Creating all four main types of custom operators Including standard error handling in custom operators Writing more fluent, readable LINQ queries with C# 4.0rs"s dynamic language features Combining LINQ with COM-Interop to access data sources such as Microsoft Excel Using Parallel LINQ to Objects (PLINQ) to optimize queries for multi-core processors Integrating the best LINQ to Objects patterns into your day-to-day coding

Author Biography

Troy Magennis is a Microsoft C# MVP and a keen traveler who currently works for Travelocity, which manages the travel and leisure websites travelocity.com, lastminute.com, and zuji. As Vice President of Architecture, he leads a talented team of architects spread across four continents, committed to being the traveler’s champion. Technology has always been a passion. After cutting his teeth on early 8-bit personal computers, Troy moved into electronic engineering (assembly language coding), which later led to positions in software application development and architecture for some of the most prominent corporations in automotive, banking, and online commerce. Troy’s first exposure to LINQ was in 2006 when he took a sabbatical to learn it and became hooked, ultimately leading him to publish the popular HookedOnLINQ website.

Table of Contents

Foreword . . . x

Preface . . . xii

Acknowledgments . . . xix

About the Author . . . xx

Chapter 1: Introducing LINQ . . . 1

What Is LINQ? . . . 1

The (Almost) Current LINQ Story . . . 3

LINQ Code Makeover–Before and After Code Examples . . . 5

Benefits of LINQ . . . 12

Summary . . . 15

References . . . 15

Chapter 2: Introducing LINQ to Objects . . . 17

LINQ Enabling C# 3.0 Language Enhancements . . . 17

LINQ to Objects Five-Minute Overview . . . 30

Summary . . . 39

References . . . 39

Chapter 3: Writing Basic Queries . . . 41

Query Syntax Style Options . . . 41

How to Filter the Results (Where Clause) . . . 49

How to Change the Return Type (Select Projection) . . . 54

How to Return Elements When the Result Is a Sequence (Select Many) . . . 59

How to Get the Index Position of the Results . . . 61

How to Remove Duplicate Results . . . 62

How to Sort the Results . . . 63

Summary . . . 73

Chapter 4: Grouping and Joining Data . . . 75

How to Group Elements . . . 75

How to Join with Data in Another Sequence . . . 93

Summary . . . 119

Chapter 5: Standard Query Operators . . . 121

The Built-In Operators . . . 121

Aggregation Operators–Working with Numbers . . . 123

Conversion Operators–Changing Types . . . 131

Element Operators . . . 144

Equality Operator–SequenceEqual . . . 153

Generation Operators–Generating Sequences of Data . . . 155

Merging Operators . . . 159

Partitioning Operators–Skipping and Taking Elements . . . 160

Quantifier Operators–All, Any, and Contains . . . 164

Summary . . . 171

Chapter 6: Working with Set Data . . . 173

Introduction . . . 173

The LINQ Set Operators . . . 174

The HashSet<T> Class . . . 185

Summary . . . 192

Chapter 7: Extending LINQ to Objects . . . 195

Writing a New Query Operator . . . 195

Writing a Single Element Operator . . . 196

Writing a Sequence Operator . . . 208

Writing an Aggregate Operator . . . 216

Writing a Grouping Operator . . . 222

Summary . . . 232

Chapter 8: C# 4.0 Features . . . 233

Evolution of C# . . . 233

Optional Parameters and Named Arguments . . . 234

Dynamic Typing . . . 243

COM-Interop and LINQ . . . 251

Summary . . . 260

References . . . 260

Chapter 9: Parallel LINQ to Objects . . . 261

Parallel Programming Drivers . . . 261

Multi-Threading Versus Code Parallelism . . . 264

Parallelism Expectations, Hindrances, and Blockers . . . 267

LINQ Data Parallelism . . . 271

Writing Parallel LINQ Operators . . . 289

Summary . . . 301

References . . . 301

Glossary . . . 303

Index . . . 307