C# Tutorials - Herong's Tutorial Examples

∟Async Feature from C# 5

Tutorial notes and examples are provided on the Async feature introduced in C# 5. Topics include introduction of Async feature; Asynchronous operations from the HttpClient class; 'await' expression examples; 'async' function examples.

What Is Async Feature?

GetStringAsync() Method in HttpClient Class

GetStringAsync() Method Example Program

Watching Asynchronous Operation Execution Status

"await" Expression and Child Thread

"await" Expression Thread Example

"async" Function Example

Takeaways:

• The Async feature allows us to create asynchronous tasks with child threads with 2 keywords: "await" and "async".
• "await" represents an "await" expression on an awaitable task.
• Evaluation of an "await" expression launches a new child thread to wait for the task to finish and continue with remaining statement of the current method.
• The calling thread of an "await" expression exits the current method immediately.
• "async" represents an "async" function that contains "await" expressions.
• "async" functions can not have any "ref" or "out" parameters.
• "async" functions must use void or Task<T> as the return type.

Table of Contents

 About This Book

 Introduction of C# (C Sharp)

 Data Type and Variables

 Logical Expressions and Conditional Statements

 Arrays and Loop Statements

 Data Type Features

 Floating-Point Data Types

 Passing Parameters to Methods

 Execution Environment Class

 Visual C# 2010 Express Edition

 Class Features

 C# Compiler and Intermediate Language

 Compiling C# Source Code Files

 MSBuild - Microsoft Build Engine

 Memory Usages of Processes

 Multithreading in C#

►Async Feature from C# 5

 System.IO.FileInfo Class

 System.Diagnostics.FileVersionInfo Class

 WPF - Windows Presentation Foundation

 Partial Classes and Partial Methods

 Archived Tutorials

 References

 Full Version in PDF/ePUB

Async Feature from C# 5 - Updated in 2022, by Herong Yang