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An Introduction to New Features in C# 5.0

An Introduction to New Features in C# 5.0

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Introduction of New Features in C# 5.0

 

1. C# Evolution Matrix

Microsoft just published a new version of C# : 5.0 beta with CLR version 4.5 (Visual Studio 11 beta).
In order to get a big picture of the whole evolution of C# language, I summarized all the key features
into a C# Evolution Matrix for your reference as below diagram shows:



In C# version 5.0, there are two key features: Async Programming and Caller Information.

2. Async Feature

Two new key words are used for Async feature: async modifier and await operator. Method marked
with async modifier is called async method. This new feature will help us a lot in async programming.
For example, in the programming of Winform, the UI thread will be blocked while we use
HttpWebRequest synchronously request any resource in the Internet. From the perspective of user
experience, we cannot interact with the form before the request is done.

private void
btnTest_Click(object sender, EventArgs e)

{

var request = WebRequest.Create(txtUrl.Text.Trim());

var content=new MemoryStream();

using (var response = request.GetResponse())

{

using (var responseStream = response.GetResponseStream())

{

responseStream.CopyTo(content);

}

}

txtResult.Text = content.Length.ToString();

}




In the above example, after we clicked the Test button, we cannot not make any change to the form
before the txtResult textbox shows the result.

In the past, we can also use BeginGetResponse method to send async request as this sample in MSDN
shows:
http://msdn.microsoft.com/zh-cn/library/system.net.httpwebrequest.begingetresponse(v=vs.80).aspx. But it
will takes us a lot effort to realize it.

Now, we can simply use below code to do request asynchronously :

private async void
btnTest_Click(object sender, EventArgs e)

{

var request = WebRequest.Create(txtUrl.Text.Trim());

var content = new MemoryStream();

Task<WebResponse> responseTask = request.GetResponseAsync();

using (var response = await responseTask)

{

using (var
responseStream = response.GetResponseStream())

{

Task copyTask = responseStream.CopyToAsync(content);

//await operator to supends the excution of the method until the task is completed. In the meantime,
the control is returned the UI thread.

await copyTask;

}

}

txtResult.Text = content.Length.ToString();

}

The await operator is applied to the returned task. The await operator suspends execution of the
method until the task is completed. Meanwhile, control is returned to the caller of the suspended
method.

3. Caller Information

Caller Information can help us in tracing, debugging and creating diagnose tools. It will help us
to avoid duplicate codes which are generally invoked in many methods for same purpose, such
as logging and tracing.

We could get the below information of caller method :

Below example are a common practice prior to the new feature of Caller Information:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace
ConsoleApplicationTest

{

class Program

{

static void Main(string[] args)

{

InsertLog("Main");

MethodB();

Console.ReadLine();

}

static void MethodA()


{

InsertLog("MethodA");

MethodB();

}

static void MethodB()


{ }

static void
InsertLog(string methodName)

{

Console.WriteLine("{0} called method B at {1}", methodName,
DateTime.Now);

}

}

}

In both Main and MethodA methods, method InsertLog is invoked for logging. Now we can change the
codes to be as per below lines:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Runtime.CompilerServices;

using System.Text;

using System.Threading.Tasks;

namespace
ConsoleApplicationTest

{

class Program

{

static void Main(string[] args)

{

//InsertLog("Main");

MethodB();

Console.ReadLine();

}

static void MethodA()


{

//InsertLog("MethodA");

MethodB();

}

static void MethodB(

[CallerMemberName] string memberName = "",

[CallerFilePath] string sourceFilePath = "",

[CallerLineNumber] int sourceLineNumber = 0)

{

InsertLog(memberName);

}

static void
InsertLog(string methodName)

{

Console.WriteLine("{0} called method B at {1}", methodName,
DateTime.Now);

}

}

}

4. Summary

The new features in C# 5.0 will help us to code more easily and improve the productivity. Have a nice
experience with the new release of Visual Studio 11!

 

Author's Bio

Fahao Tang, Visual C# MVP, majored in Environment Engineering. In 2008, he joined
Microsoft
MSDN forums and became a moderator one year later.  Through these
forums, he helped a lot of users to resolve all kinds of questions and issues. In 2012,
he successfully joined one of the GSO hubs of the
Australia and New Zealand Banking
Group in Chengdu. The new role as Senior MIS
Developer as well as the youngest
senior developer in the department, brings
him a lot challenges with opportunities. 
Beside the improvement in work,
he also helped to organize offline technique sharing
meetings.  He is
currently a programmer and an information participator and initiator. 

MVP Mondays

The MVP Monday Series is created by Melissa Travers. In this series we work to
provide readers with a guest post from an MVP every Monday. Melissa is a
Community Program Manager for Dynamics, Excel, Office 365, Platforms and
SharePoint in the United States. She has been working with MVPs since her
early days as Microsoft Exchange Support Engineer when MVPs would answer
all the questions in the old newsgroups before she could get to them.

 

Leave a Comment
  • Please add 1 and 3 and type the answer here:
  • Post
  • The blog software is poor in handling source code. Improve this, Microsoft!

  • is this visual studio 2011 r 2012?

  • Oh, Microsoft had VS 2011 ? I never knew that.

    Guess it should have been VS 2012.

  • excellent artical.......

  • Good information..

  • Thanks for sharing. Very use full information.

  • That's all? Boring...

  • MSDN should provide proofreaders to bloggers with poor English.

  • Async and await is working with VS2010 as well

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