Book Image

C# Programming Cookbook

By : Dirk Strauss
Book Image

C# Programming Cookbook

By: Dirk Strauss

Overview of this book

During your application development workflow, there is always a moment when you need to get out of a tight spot. Through a recipe-based approach, this book will help you overcome common programming problems and get your applications ready to face the modern world. We start with C# 6, giving you hands-on experience with the new language features. Next, we work through the tasks that you perform on a daily basis such as working with strings, generics, and lots more. Gradually, we move on to more advanced topics such as the concept of object-oriented programming, asynchronous programming, reactive extensions, and code contracts. You will learn responsive high performance programming in C# and how to create applications with Azure. Next, we will review the choices available when choosing a source control solution. At the end of the book, we will show you how to create secure and robust code, and will help you ramp up your skills when using the new version of C# 6 and Visual Studio
Table of Contents (21 chapters)
C# Programming Cookbook
Credits
About the Author
Acknowledgements
About the Reviewer
www.PacktPub.com
Preface
Index

Creating code contract ValueAtReturn method


The best example we can think of when using the code contract ValueAtReturn is out parameters. Personally, I do not use out parameters often, but there are times when you need to use them. Code contracts make provision for this, and you can check the value at the time it is returned.

Getting ready

We will create a simple method that subtracts a value from a parameter. The out parameter will be validated by the code contract, and the result will be output to the console window.

How to do it…

  1. Before you go on, ensure that you have added the code contracts using statement to the top of your Recipes.cs class file:

    using System.Diagnostics.Contracts;
  2. In the Recipes class, create a new method called ValidOutValue() and pass an out parameter called secureValue to it:

    public static void ValidOutValue(out int secureValue)
    {
        
    }
  3. Finally, add Contract.ValueAtReturn to the method. Interestingly, you will note that this needs to be contained in Contract.Ensures...