Metaprogramming in C#: Automate your .NET development and simplify overcomplicated code

Cover....1

Title Page....2

Copyright and Credits....3

Contributors....4

Table of Contents....6

Preface....12

Part 1: Why Metaprogramming?....18

Chapter 1: How Can Metaprogramming Benefit You?....20

Reasoning about your code....20

Developer concerns....21

Automation....22

Metaprogramming....22

Removing manual structure and process....24

Maintaining software....25

Generating code....25

Compile time safety....27

Summary....28

Chapter 2: Metaprogramming Concepts....30

Technical requirements....30

Implicit – using what is already there....31

Leveraging the power of reflection....32

Explicit – additional adornment of code....35

Creating custom attributes....36

Domain-specific languages....38

Gherkin – technical sample....39

Summary....41

Chapter 3: Demystifying through Existing Real-World Examples....42

Technical requirements....42

Prerequisites for your system....43

ASP.NET controllers....43

Custom HTTP Get handler....44

Controller....46

ASP.NET validation....47

Automatically hooking up model state handling....50

Summary....52

Part 2: Leveraging the Runtime....54

Chapter 4: Reasoning about Types Using Reflection....56

Technical requirements....56

Assembly discovery in the running process....57

Assembly....57

Leveraging library metadata to get project referenced assemblies....58

Reusable fundamentals....59

Business app....62

Discovering types....63

Back to business....64

Domain concepts....66

Cross-cutting concerns....68

Open/closed principle applied....70

Summary....71

Chapter 5: Leveraging Attributes....72

Technical requirements....72

What is an attribute and how can it be applied?....72

Limiting attribute usage....74

Sealing your attribute class....76

Finding types with specific attributes....77

Personal Identifiable Information (PII)....77

Generic attributes....81

Summary....83

Chapter 6: Dynamic Proxy Generation....84

Technical requirements....84

An introduction to IL and Reflection.Emit....84

Creating a dynamic assembly and module....85

Virtual members and overrides....91

Implementing an interface....92

NotifyObjectWeaver class....94

Summary....105

Chapter 7: Reasoning about Expressions....106

Technical requirements....106

What are expressions?....107

Expression....109

Lambda expression....111

Traversing an expression tree....112

Using expressions as descriptors of members on types....115

Summary....118

Chapter 8: Building and Executing Expressions....120

Technical requirements....120

Creating your own expressions....121

Creating expressions as delegates and executing them....122

Creating a query engine....123

A MongoDB-like database....124

Building a simple query engine....125

Summary....132

Chapter 9: Taking Advantage of the Dynamic Language Runtime....134

Technical requirements....134

Understanding the DLR....135

The CLR at a glance....135

The DLR building blocks....136

Call sites and binders....138

Reasoning about a dynamic type....138

Creating DynamicObject and providing metadata....141

Building a JSON schema type....142

Summary....150

Part 3: Increasing Productivity, Consistency, and Quality....152

Chapter 10: Convention over Configuration....154

Technical requirements....154

Inversion of control and its role....155

Refactoring the code....160

Automatic ServiceCollection registrations by convention....166

Further refactoring....167

Composing....171

Summary....175

Chapter 11: Applying the Open-Closed Principle....178

Technical requirements....179

Encapsulating type discovery....180

Encapsulating the discovery of instances....182

Hooking up with the service collection....183

Practical use case....184

Helping the developer....187

Supporting properties....189

Using the GDPR infrastructure....191

Adding more providers....195

Summary....197

Chapter 12: Go Beyond Inheritance....198

Technical requirements....198

Method signature conventions....198

Infrastructure....202

Using the infrastructure....211

Summary....215

Chapter 13: Applying Cross-Cutting Concerns....216

Technical requirements....216

What are cross-cutting concerns?....217

Leveraging the ASP.NET pipeline....218

Building consistent result objects....218

CommandResult....220

Authorization based on metadata or structure....229

Summary....240

Chapter 14: Aspect-Oriented Programming....242

Technical requirements....242

What is AOP?....242

Aspects....243

Pointcuts....243

Join points....244

Logging....245

Creating a logging sample....246

Adding the Microsoft logger....247

Interceptors....249

Trying out the interceptor....252

Mixins....255

Mixing it up....256

Authorization....262

Using pointcuts....263

Summary....269

Part 4: Compiler Magic Using Roslyn....270

Chapter 15: Roslyn Compiler Extensions....272

Technical requirements....272

How to set up a project and its moving parts....272

What can they do?....273

Setting it up....274

Adding common rules....276

Common project settings....278

How to package your extension for reuse....280

Common package properties....281

Analyzer....282

Summary....284

Chapter 16: Generating Code....286

Technical requirements....287

Generating additional code for the Roslyn compiler....287

ASTs....287

Application metrics....288

Improving the developer experience....292

(Ab)using the compiler to generate not just C# code....305

Building the generator....306

Improving the developer experience....311

Debugging....311

Optimization....312

Summary....312

Chapter 17: Static Code Analysis....314

Technical requirements....315

What is static code analysis?....315

How to write an analyzer....316

Fleshing out an analyzer....316

Handling the syntax nodes....319

Release tracking....320

Trying out the analyzer....322

How to write a code fix for an analyzer....324

How to write automated tests....327

Analyzer tests....328

Code fix tests....330

Summary....332

Chapter 18: Caveats and Final Words....334

Performance implications....334

Hidden magic – handle with care....335

When to use what....336

Summary....337

Index....338

Other Books You May Enjoy....347

Metaprogramming is an advanced technique that helps developers to automate repetitive tasks, generate scalable code, and enhance productivity in software development. Metaprogramming in C# is a comprehensive guide that will help you reap the full potential of metaprogramming in .NET runtime.

You'll start by learning about the .NET runtime environment and how you can use it to become a more productive developer. You'll learn how to infer types using reflection, use attributes, and create dynamic proxies. You'll also explore the use of expressions to create and execute code and how to take advantage of Dynamic Language Runtime.

But that's not all! You'll also learn to go beyond inheritance and use method signature conventions to create easily maintainable code. Finally, you'll dive into the world of compiler magic with Roslyn, where you'll discover how to use Roslyn to generate code, perform static code analysis, and write your own compiler extensions.

By the end of this book, you'll have a deep understanding of metaprogramming concepts and how to apply them to your C# code. You'll be able to think about types, use attributes and expressions to generate code, and apply crosscutting concerns to improve code quality.

What You Will Learn:

• Explore how to leverage the .NET runtime
• Improve code quality and increase productivity
• Write adaptable code for changing requirements
• Learn Roslyn for code generation and static analysis
• Master metaprogramming and its practical implementations
• Use Dynamic Language Runtime for flexible and expressive programming

Who this book is for:

 This book is for C# developers interested in learning about the .NET runtime and how to leverage it for writing maintainable, scalable, and secure code. Software architects who are responsible for designing and managing complex software solutions will also benefit from the book.