1. The Future of C# and Visual Basic
5/18/2018 3:17 AM
The Future of C# and Visual Basic
Anders Hejlsberg
Technical Fellow
Microsoft Corporation
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

2. C# and VB Evolution C# 4.0 + VB 10.0 Dynamic + Language Parity
Language Integrated Query
C# VB 8.0
Generics
C# VB 7.0
Managed Code

3. Trends
Declarative
Concurrent
Dynamic

4. Trends Increasingly connected applications Asynchronous programming
More latency
More UI responsiveness problems
More scalability issues
Asynchronous programming
Becoming the norm in responsive, scalable apps
Async-only APIs, e.g. JavaScript and Silverlight

5. C# and VB Evolution C# + VB v.Next Asynchronous Programming
Dynamic + Language Parity
C# VB 9.0
Language Integrated Query
C# VB 8.0
Generics
C# VB 7.0
Managed Code

6. Asynchrony in a Nutshell
Synchronous  Wait for result before returning
string DownloadString(...);
Asynchronous  Return now, call back with result
void DownloadStringAsync(..., Action<string> callback);
Asynchrony benefits
UI responsiveness: Frees UI thread for interaction
Server scalability: Thread can be reused for other requests

7. Synchronous vs. Asynchronous
var data = DownloadData(...);
ProcessData(data);
STOP
ProcessData
DownloadData
Thread
DownloadDataAsync(... , data => {
ProcessData(data);
});
Thread
DownloadDataAsync
ProcessData

8. Synchronous vs. Asynchronous
var data = DownloadData(...);
ProcessData(data);
STOP
ProcessData
DownloadData
STOP
Thread
DownloadDataAsync(... , data => {
ProcessData(data);
});
Thread
DownloadDataAsync
ProcessData

9. Asynchronous Responsive UI
5/18/2018 3:17 AM
Asynchronous Responsive UI
demo
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

10. Visual Studio Async CTP
5/18/2018 3:17 AM
Visual Studio Async CTP
announcing
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

11. Asynchronous Methods Framework: Use Task<T> for all asynchrony
Goal: Just like synchronous programming
You can have your cake and eat it too!
Framework: Use Task<T> for all asynchrony
Add Task<T> support to existing .NET and Silverlight APIs
Easy for you to do the same
Languages: Asynchronous Methods
“async” modifier marks method or lambda as asynchronous
“await” operator yields control until awaited task completes

12. Task<T> Represents “ongoing operation” Composable callback model
Could be async I/O, background worker, anything...
Single object for status, result and exceptions
Composable callback model
var task2 = task1.ContinueWith(t => … t.Result …);
The “await” operator rewrites to continuations
Combinators
WhenAll, WhenAny, Delay, etc.

13. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); }
Message Pump
UI Thread

14. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); }

15. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); }

16. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); }

17. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1

18. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2

19. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2

20. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2 

21. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2 

22. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2  

23. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2  

24. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2   

25. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2    

26. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2     

27. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2      

28. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2       

29. Asynchronous Control Flow
async void DoWorkAsync() {
var t1 = ProcessFeedAsync("
var t2 = ProcessFeedAsync("
await Task.WhenAll(t1, t2);
DisplayMessage("Done"); }
async Task ProcessFeedAsync(string url) {
var text = await DownloadFeedAsync(url);
var doc = ParseFeedIntoDoc(text);
await SaveDocAsync(doc);
ProcessLog.WriteEntry(url); } t1 t2       

30. How Does it Work? async Task<XElement> GetRssAsync(string url) {
var client = new WebClient();
var task = client.DownloadStringTaskAsync(url);
var text = await task;
var xml = XElement.Parse(text);
return xml; }

31. How Does it Work? Task<XElement> GetRssAsync(string url) {
var $builder = AsyncMethodBuilder<XElement>.Create();
var $state = 0;
TaskAwaiter<string> $a1;
Action $resume = delegate {
try {
if ($state == 1) goto L1;
var client = new WebClient();
var task = client.DownloadStringTaskAsync(url);
$state = 1;
$a1 = task.GetAwaiter();
if ($a1.BeginAwait($resume)) return;
L1: var text = $a1.EndAwait();
var xml = XElement.Parse(text);
$builder.SetResult(xml); }
catch (Exception $ex) { $builder.SetException($ex); } };
$resume();
return $builder.Task;
async Task<XElement> GetRssAsync(string url) {
var client = new WebClient();
var task = client.DownloadStringTaskAsync(url);
var text = await task;
var xml = XElement.Parse(text);
return xml; }

32. Asynchronous Web Servers
5/18/2018 3:17 AM
Asynchronous Web Servers
demo
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

33. Unifying Asynchrony An asynchronous scenario
Asynchronous Methods
Task
An asynchronous scenario
Scrape YouTube for video links
Download two or more videos concurrently
Create a mashup from downloaded videos
Save the resulting video
CPU
Network
I/O
Composite

34. Unifying Asynchrony Task CPU Network I/O Composite try {
string[] videoUrls = await ScrapeYoutubeAsync(url); // Network-bound
Task<Video> t1 = DownloadVideoAsync(videoUrls[0]); // Start two downloads
Task<Video> t2 = DownloadVideoAsync(videoUrls[1]);
Video[] vids = await Task.WhenAll(t1, t2); // Wait for both
Video v = await MashupVideosAsync(vids[0], vids[1]); // CPU-bound
await v.SaveAsync(textbox.Text); // IO-bound }
catch (WebException ex) {
ReportError(ex);

35. Download Visual Studio Async CTP today!
Asynchronous Methods
As simple as synchronous code
Unifies computational, network and I/O asynchrony
More scalable servers
More responsive UI
Download Visual Studio Async CTP today!

36. C# and VB Evolution C# + VB v.Next Asynchronous Programming
Dynamic + Language Parity
C# VB 9.0
Language Integrated Query
C# VB 8.0
Generics
C# VB 7.0
Managed Code

37. Compiler as a Service Compiler Compiler Meta-programming
Class
Field
public
Foo
private
string X
Meta-programming
Read-Eval-Print Loop
Language
Object Model
DSL Embedding
Compiler
Compiler
Source File
.NET Assembly
Source code
Source code
Source code
Source code

38. demo Compiler as a Service 5/18/2018 3:17 AM
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

39. More Information Visual Studio Async CTP Related Talks
Related Talks
LINQ, Take Two: Realizing the LINQ to Everything Dream
Programming Languages Panel
Building Web APIs for the Highly Connected Web
The Future of F#: Data and Services at your Finger Tips

40. 5/18/2018 3:17 AM
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
© 2009 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.