What's New in .Net 4.5

Improvements to
• WeakReferences

• ArraySegment

• Streams

• ReadOnlyDictionary

• Compression

• Bigger than 2GB Objects

Background Server GC
• Shorter pauses when doing Gen2 Collections

(Server GC) Scalable Marking for full blocking GCs

Large Object Heap Allocation Improvements
• Better use of free space on LOH

• Balancing the LOH allocations across processors (Server only)

• Up to 2GB Large Array on 32bit and more then 2GB on 64bit
Systems

public class SomeClass {

public void DownloadStringAsync() {

WebClient wc1 = new WebClient();

wc1.DownloadStringCompleted += (sender, e) => {
string res = e.Result;
};

wc1.DownloadStringAsync(new Uri("http://www.SomeWeb.../"));
}
}

public class SomeClass {

public async void DownloadStringAsync() {

WebClient web = new WebClient();

string res = await web.DownloadStringAsync("www.SomeWeb...");
}
}

Two keywords for asynchronous programming:
The method signature includes an Async or async
modifier.

The name of an async method, by convention, ends
with an "Async" suffix.

The return type is one of the following types:
 Task<TResult> if the method has a return statement in
which the operand has type TResult.
 Task if the method has no return statement or has a
return statement with no operand.
 Void (a Sub in Visual Basic) if its an async event handler.

The method usually includes at least one await
expression, which marks a point where the
method can't continue until the awaited
asynchronous operation is complete.
In the meantime, the method is suspended, and
control returns to the method's caller.

• These features add a task-based model for
performing asynchronous operations. To use
this new model, use the asynchronous methods
in the I/O classes.

• Asynchronous operations enable you to perform
resource-intensive I/O operations without
blocking the main thread.

• This performance consideration is particularly
important in a Windows Metro style app or
desktop app where a time-consuming stream
operation can block the UI thread and make your
app appear as if it is not working.

async void DisplayUserInfo(string userName) {
var image = FetchUserPictureAsync(userName);
var address = FetchUserAddressAsync(userName);
var phone = FetchUserPhoneAsync(userName);
await Task.WhenAll(image, address, phone);
DisplayUser(image.Result, address.Result,
phone.Result);
}
 Client UI Code
• Easy to write client UI code that doesn’t block
 Business logic
• Easy to write code that fetches data from multiple sources in
parallel
 Server code
• Better scalability – no need to have a thread per request.
 New APIs in BCL, ASP.NET, ADO.NET, WCF, XML, WPF

 Combinators
Task.WhenAll, Task.WhenAny
 Timer integration
Task.Delay(TimeSpan),
CancellationTokenSource.CancelAfter(TimeSpan)
 Task scheduling
ConcurrentExclusiveSchedulerPair
 Fine-grained control
DenyChildAttach, HideScheduler, LazyCancellation,
EnumerablePartitionerOptions
 ThreadLocal<T>.Values

 PERFORMANCE (“it’s just faster”)

The Managed Extensibility Framework (MEF)
provides the following new features:
 Support for generic types.
 Convention-based programming model that enables to
create parts based on naming conventions rather than
attributes.
 Multiple scopes.
 A subset of MEF that you can use when you create Metro
style apps. This subset is available as a downloadable
package from the NuGet Gallery.

 All your objects are MEF now
• Generics
• POCO
• Explicit Wiring (wire specific MEF parts the way YOU
want)

 MEF problems are easy to diagnose
• Break on First Chance Exceptions
• Visualize the exception
• Fix your problem!

Resource File Generator (Resgen.exe)
- enables you to create a .resw file for use in
Windows apps from a .resources file embedded in a
.NET Framework assembly.

Managed Profile Guided Optimization
(Mpgo.exe)
- enables you to improve application startup time,
memory utilization (working set size), and
throughput by optimizing native image assemblies.
The command-line tool generates profile data for
native image application assemblies.

Improved performance, increased control,
improved support for asynchronous
programming, a new dataflow library, and
improved support for parallel debugging and
performance analysis.
The performance of TPL, such that just by
upgrading to .NET 4, important workloads will
just get faster, with no code changes or even
recompilation required.

More queries in .NET 4.5 will now automatically
run in parallel. A prime example of this is a

ASP .NET 4.5 includes the following new
features:
• Support for new HTML5 form types.

• Support for model binders in Web Forms. These let you
bind data controls directly to data-access methods, and
automatically convert user input to and from .NET
Framework data types.
• Support for unobtrusive JavaScript in client-side
validation scripts.
• Improved handling of client script through bundling and
minification for improved page performance.
• Integrated encoding routines from the AntiXSS library

• Support for WebSockets protocol.

• Support for reading and writing HTTP
requests and responses asynchronously.

• Support for asynchronous modules and
handlers.

• Support for content distribution network
(CDN) fallback in the ScriptManager
control.

The ASP.NET Web API takes the best features from WCF Web
API and merges them with the best features from MVC.

The integrated stack supports the following
features:












From 353,5 KB
+ multiple call
overhead

+84% improvement
To 59.83 KB
+ one call
overhead

 Two ways to run ASP.NET
• Start app, keep it running
• Start when a request comes in (e.g. Hosters)

 35% faster cold start
• Multi-core JIT
• Windows Server 8 pre-fetch option

 Working set improvements

 Even more support for SQL Server 2008 2012
• Null bit compression for sparse columns

 Support for new Denali features
• Support for High Availability
 Just set the correct keyword in the connection string
 Fast Failover across multiple subnets
• Support for new Spatial Types (GIS)

 More good stuff
• Passwords encrypted in memory
• Async support

• Spatial data support

• Table valued functions

• Stored procs with multiple result sets

• Automatic compiled LINQ queries

• Query optimization

• Runs on it’s own cadence – so more features &
improvements more often

• Enum support throughout

• Support for localdb

• Designer improvements!
(Multiple diagrams per model)

 Improve Developer Productivity
• Enums
• Migrations
• Batch Sproc Import
• Designer highlighting and coloring

 Enable SQL Server and Azure Features
• Spatial (Geometry and Geography)
• Table-valued functions
• Sprocs with multiple result sets

 Increase Enterprise Readiness
• Multiple diagrams per model
• TPT query optimizations
• Automatic compiled LINQ queries

The .NET Framework 4.5 provides a new programming
interface for HTTP applications.
New System.Net.Http and System.Net.Http.Headers namespa
ces.
A new programming interface for accepting and interacting
with a WebSocket connection by using the
existing HttpListener and related classes
The .NET Framework 4.5 includes the following networking
improvements:
• RFC-compliant URI support. For more information,
see Uri and related classes.
• Support for Internationalized Domain Name (IDN) parsing.

 Simplified Generated Configuration Files
• New Transport Default Values
• XmlDictionaryReaderQuotas

 Contract-First Development
 WCF Configuration Validation
• XML Editor Tooltips
• Configuration Intellisense

 ASP.NET Compatibility Mode Default Changed
 Simplifying Exposing an Endpoint Over HTTPS with
IIS
 Generating a Single WSDL Document
 Streaming Improvements
• Async Streaming

 WebSocket Support
 ChannelFactory Caching

 Scalable modern communication stack
• Interoperable UDP multi-cast channel
• TCP support for high-density scenarios (partial
trust)
• Async
• Improved streaming support

 Continued commitment to simplicity
• Further config simplification, making WCF
throttles/quotas smarter & work for you by default!
• Better manageability via rich ETW & e2e tracing

 The New Ribbon Controls
 Validating data asynchronously and synchronously
 Data Binding Changes
• Improved performance when displaying large sets of
grouped data
• Delay property binding
• Accessing collections on non-UI Threads
• Binding to static properties
• And more!
 Markup extensions for events
 ItemsControl Improvements
 New features for the VirtualizingPanel
 Improved Weak Reference Mechanism

OOM
at 7
min

24.5s
2.3s

 .NET 4.5 is an in-place update that helps us make
sure it is highly compatible.
 .NET 4.5 makes it easy and natural to write Metro
style apps using C# and VB
 .NET 4.5 makes your apps run faster: Faster ASP.NET
startup, fewer pauses due to Server GCs, and great
support for Asynchronous programming
 .NET 4.5 gives you easy, modern access to your data,
with support for Entity Framework Code First, and
recent SQL Server features, and WebSockets
 .NET 4.5 addresses the top developer requests in
WPF, Workflow, BCL, MEF, and ASP.NET

What's New in .Net 4.5

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