VB.NET

Introduction to The One ASP.NET Platform/Ecosystem

December 25, 2012 .NET, .NET Framework, .NET Framework 4.5, ADO.NET, All, ASP.NET, ASP.NET 4.5, ASP.NET AJAX, ASP.NET MVC, ASP.NET MVP, C#.NET, Community, HTML, HTML5, IIS, JavaScript, JavaScript, jQuery, JQuery Mobile, KnowledgeBase, LINQ, Microsoft, MSDN, SignalR, Updates, VB.NET, VisualStudio, VS2012, WCF, Web, Web API No comments

Introduction

ASP.NET has travelled a long way through evolutions. Earlier when ASP.NET 1.0 was released as part of .NET Framework 1.0 in Jan 2002, there was only ASP.NET – a framework for building dynamic web applications and it provided lots of flexibility web developers in building robust, dynamic web applications.  ASP.NET was and is the successor to Microsoft’s Active Server Pages (ASP) technology.

ASP.NET is built on the Common Language Runtime (CLR), allowing programmers to write ASP.NET code using any supported .NET language. The ASP.NET SOAP extension framework allows ASP.NET components to process SOAP messages.

From that, today we reached ASP.NET 4.5 and platform/web framework has changed a lot through the 10 years of journey.

Before going further lets go through a quick summery of additions in each releases:

ASP.NET 1.0 (January 16, 2002)

  • Object-oriented Web application development supporting inheritance, polymorphism and other standard OOP features
  • Support for generic HTML controls and ASP.NET dynamic web controls
  • Event based programming
  • The developer can make use of DLL class libraries and other features of the Web server to build more robust applications that do more than simply rendering HTML.
  • Integrated development support using Visual Studio .Net 2002

ASP.NET 1.1 (April 24, 2003)

  • With ASP.NET 1.1 – an update to .NET framework 1.0 called as .Net framework 1.1 – we received support for Mobile Web Controls, Automatic input validation
  • Integrated development support using Visual Studio .Net 2003

ASP.NET 2.0 (November 7, 2005)

ASP.NET 2.0 introduced major updates to ASP.NET framework with introduction of Master pages and new data controls.

The interesting features included in this release were:

  • Integrated development support using Visual Studio 2005
  • New data controls (GridView, FormView, DetailsView)
  • New technique for declarative data access (SqlDataSource, ObjectDataSource, XmlDataSource controls)
  • Navigation controls
  • Master pages
  • Login controls
  • Themes
  • Skins
  • Web parts
  • Personalization services
  • Full pre-compilation
  • New localization technique
  • Support for 64-bit processors
  • Provider class model
  • Web Sites projects are introduced. An alternative to Web Application project model in earlier versions.
  • ASP.NET AJAX has been introduced as a separate installer. Included ScriptManager, UpdatePanel etc.

ASP.NET 3.5 (November 19, 2007)

This was an incremental update to ASP.NET 2.0 and .NET Framework 2.0. Base level the Runtime was depending on .NET Framework 2.0 and set of additional runtime extension components been introduced in this release.

The interesting features included in this release were:

  • Integrated development support using Visual Studio 2008
  • New data controls (ListView, DataPager, LinqDataSource)
  • ASP.NET AJAX included as part of the framework
  • Support for HTTP pipelining and syndication feeds.
  • WCF support for RSS, JSON, POX and Partial Trust
  • All the .NET Framework 3.5 changes, like LINQ etc.

With .NET Framework 3.5 Service Pack 1, some more features been introduced

  • Integrated development support using Visual Studio 2008 – Service Pack 1
  • Incorporation of ASP.NET Dynamic Data
  • Entity Framework support
  • Support for controlling browser history in an ASP.NET AJAX application
  • Ability to combine multiple JavaScript files into one file for more efficient downloading
  • New namespaces System.Web.Abstractions and System.Web.Routing
  • JQuery is included as part of the template.
  • ASP.NET MVC is born

Now ASP.NET framework is spitted in to three based on the purpose

ASP.NET Core Services – all the major ASP.NET runtime components has been built in to this and will act as a base layer for all other ASP.NET components such as Web Forms, MVC, Dynamic Data etc.

Now we have three Presentation Frameworks/Components that utilizes the ASP.NET Core runtime components

  1. ASP.NET Web Forms – based on traditional ASP.NET web application model – dynamic *.aspx pages with code behind file.
  2. ASP.NET MVC – based on MVC model – *.aspx pages for View, no code behind file. Simply depended on Controller and model.
  3. ASP.NET Dynamic data – the quick and easy – rapid application development model with help of LINQ and Entity Framework. ASP.NET Dynamic Data helps you quickly build a fully customizable, data-driven application without writing code. Dynamic Data provides a rich scaffolding framework that is easily extensible by using the traditional ASP.NET programming model.

ASP.NET 4.0 (April 12, 2010)

The .NET Framework version 4 includes enhancements for ASP.NET 4 in targeted areas. Visual Studio 2010 and Microsoft Visual Web Developer Express also include enhancements and new features for improved Web development.

The interesting features included in this release were:

  • Integrated development support using Visual Studio 2010
  • jQuery Included with Web Forms and MVC
  • Content Delivery Network Support
  • Setting Meta Tags with the Page.MetaKeywords and Page.MetaDescription Properties
  • ASP.NET MVC 3.0 with Web Pages and razor support
  • IISExpress Support through Service Pack1
  • and more… You can read about it in detail on the MSDN page What’s New in ASP.NET 4 and Visual Web Developer

 

ASP.NET 4.5 (August 15, 2012)

This was a long awaited release since ASP.NET 4.0, which includes the new improved support for Web Pages, MVC and new Web API support. With the release of .NET Framework 4.5 and Visual Studio 2012, decided to go away from Service Packs and release incremental updates whenever available.

The interesting features included in this release were:

  • Async support – HttpRequest, Response, HTTP Modules and Handlers are capable of handling Async request and responses.
  • AntiXSS library is integrated
  • WebSockets protocol support
  • Lazy request validation
  • ASP.NET Web Forms – Model binding similar to ASP.NET MVC
  • HTML5 support
  • ASP.NET MVC 4, Web Pages 2.0, Web API, ASP.NET MVC 4 – Mobile Web Templates using jQuery Mobile
  • and more… You can read about it in detail on the MSDN page What’s New in ASP.NET 4.5 and Visual Web Developer

ASP.NET and Web Tools 2012.2 update

This .2 update adds a number of new templates and features including:

  • Enhancements to Web Publishing
  • New Web API functionality
  • New templates for Facebook Application and Single Page Application
  • Real-time communication via ASP.NET SignalR
  • Extensionless Web Forms via ASP.NET Friendly URLs
  • Support for the new Windows Azure Authentication
  • and more… You can read about it in detail on the MSDN page What’s New in ASP.NET and Web Tools 2012.2 Update

SignalR

SignalR is a new member of the ASP.NET family that facilitates adding real-time functionality to web applications using WebSockets and other down-level transports. SignalR is a self-contained library installed via NuGet that is targeting a 1.0 RTW as part of the Fall Update. This will include item templates for adding SignalR connections and hubs to an ASP.NET application as well as a full project template that integrates with ASP.NET MVC and ASP.NET Web API.

[ Quoted from http://aspnet.codeplex.com  ]

THE ONE ASP.NET PLATFORM

Now the ASP.NET ecosystem would look as in the image, with 2012.2 release: Single platform – multiple, extensible solutions

All the parts of ASP.NET, all the subsystems are all part of the larger ASP.NET community 

[Image courtesy Scott Hanselman’s blog]

Scott Hanselman of Microsoft Quotes:

The idea behind One ASP.NET is that we want folks to be able to make apps that have real-time components with SignalR, clean, simple APIs with Web API, all in one pages with KnockoutJS, pages with MVC, Web Forms or Web Pages, as well as existing ASP.NET systems like OData, ASMX, and more.

We want open source projects like JSON.NET, KnockoutJS, SignalR, Backbone, MongoDB, Scaffolding, NHIbernate, Ninject (and the list goes on) to all play in the same ASP.NET LEGO sandbox.

We’ll put all these subcomponents on NuGet and they’ll live alongside community components and you’ll be able to build ASP.NET applications starting from some base template and add just the pieces you want. We are getting there. We want folks to use the parts they want, and swap out the parts they don’t. Everything should work together.

ScottGu Quotes
The new runtime functionality is delivered to ASP.NET via additional NuGet packages. This means that installing this update does not make any changes to the existing ASP.NET binaries, and thus does not cause any compatibility issues with existing projects. New projects will contain the new functionality and existing projects can be updated with the new NuGet packages.

You can further read about it through Scott Hanselman’s article and ScottGu’s blog 
 

Conclusion

Now with ASP.NET 4.5 and Updates we reached a place where we have a vast variety of technologies to choose from, to develop rich, dynamic web applications for Desktop browsers as well as for mobile browsers.

ASP.NET Ecosystem is growing and is moving in the right pace with the release to open source development of most of the components through http://aspnet.codeplex.com/ 

It is challenging and interesting for ASP.NET developers to be able to develop using such cutting edge technologies.

Information Sources & Courtesy: Wikipedia, MSDN and Microsoft Developer blogs

Zip(Archive) API’s in .NET Framework 4.5 – Part 2 – ZipFile Class

October 22, 2012 .NET, .NET Framework, .NET Framework 4.5, All, Back-2-Bascis, BCL(Base Class Library), C#.NET, Codes, CodeSnippets, DevLabs, Foundations, Help Articles, KnowledgeBase, Microsoft, Updates, VB.NET, VisualStudio, VS2012, Windows No comments

In my previous post I shared some information on API’s/Classes included as part of System.IO.Compression namespace in .NET Framework 4.5, and given on overview of ZipArchive class. Once such class I would be sharing some insight with post today would be ‘ZipFile‘ class. The ZipFile class provides convenient static methods for working with zip archives:

  1. CreateFromDirectory (3 overloads) – Creates a zip archive that contains the files and directories from the specified directory, uses the specified compression level and character encoding for entry names, and optionally includes the base directory.
  2. ExtractToDirectory ( 3 overloads) – Extracts all the files in the specified zip archive to a directory on the file system and uses the specified character encoding for entry names.
  3. Open (2 overloads) – Opens a zip archive at the specified path, in the specified mode, and by using the specified character encoding for entry names.
  4. OpenRead  – Opens a zip archive for reading at the specified path.

 

To use these methods, you must reference the System.IO.Compression.FileSystem assembly in your project.

image

NB:

  • The System.IO.Compression.FileSystem assembly is not available for Windows Store apps. Therefore, the ZipFile class and ZipFileExtensions class (which is also in the System.IO.Compression.FileSystem assembly) are not available in Windows Store apps.
  • In Windows Store apps, you work with compressed files by using the methods in the ZipArchive, ZipArchiveEntry, DeflateStream, and GZipStream classes.

 

Now the time for creating some sample application.

For the purpose of explaining how to use the above methods – I followed the below steps :

  1. Created a console application in visual studio.
  2. Added Reference to System.IO.Compression and System.IO.Compression.FileSystem assemblies which is part of .NET Framework 4.5.
  3. Created a folder called “Files” and created some plain text files(.txt extension) , this would be out source folder to zip. And created two additional folder for storing zip files(Output) and ExtractLocation folder to extract the zip files.
  4.  image image
  5. and the below sample code snippet is the implementation/usage.
<code>&lt;p&gt;Sample code snippet:&lt;/p&gt; &lt;div&gt; &lt;pre class="brush: c#;"&gt;
</code>

namespace ConsoleApp02
{
class Program
{
static void Main(string[] args)
{
// AppDomain.CurrentDomain.BaseDirectory refers to the
//folder in which the executable or binaries are executing.
// E.g. ConsoleApp02ConsoleApp02binDebug
string startPath = AppDomain.CurrentDomain.BaseDirectory + "\Files";
string zipPath = AppDomain.CurrentDomain.BaseDirectory + "\Output";
string zipFilePath = zipPath + "\" + System.Guid.NewGuid().ToString() + ".zip";

<code>        string extractPath = AppDomain.CurrentDomain.BaseDirectory + &amp;quot;\ExtractLocation&amp;quot;;

        //just a fail-safe to create folders if not exists.
        if (!Directory.Exists(zipFilePath))
            Directory.CreateDirectory(zipFilePath);

        if (!Directory.Exists(extractPath))
            Directory.CreateDirectory(extractPath);

        //Creating a zipFile from folder
        ZipFile.CreateFromDirectory(startPath, zipFilePath);

        //Unzipping a zipFile to a folder
        ZipFile.ExtractToDirectory(zipFilePath, extractPath);

        //
        Console.WriteLine(&amp;quot;Press Any key to exit...&amp;quot;);

        Console.ReadKey();
    }
}
</code>

}

Hope this post is informative. Please keep share this post and give your comments/feedback. Happy coding!

Zip(Archive) API’s in .NET Framework 4.5 – ZipArchive Class

October 22, 2012 .NET, .NET Framework, .NET Framework 4.5, All, Back-2-Bascis, C#.NET, Codes, CodeSnippets, General, Help Links, KnowledgeBase, Microsoft, Samples, VB.NET, VisualStudio, VS2012 1 comment

With release of .NET Framework 4.5, Microsoft has introduced new classes in to System.IO.Compression namespace. These classes will add the necessary programming support for Zipping(Achiving), and Extracting support for Zip Files in your .NET Source Code.

Below are the newly introduced classes as part of .NET Framework 4.5:

ZipArchive – Represents a package of compressed files in the zip archive format.

ZipArchiveEntry – Represents a compressed file within a zip archive.

ZipFile – Provides static methods for creating, extracting, and opening zip archives.

ZipFileExtensions – Provides extension methods for the ZipArchive and ZipArchiveEntry classes.

In this blog post I am going to discuss about ZipArchive class which will help you with most of the important tasks in Archiving a file or folder using .NET.

The ZipArchive class enables you to work with a package of compressed files. The package contains an entry for each compressed file. You can:

  • Retrieve an entry by using the GetEntry method.
  • Retrieve the entire collection of entries by using the Entries property.
  • Create a new entry in the package by calling the overloaded CreateEntry method.

If you add reference for the System.IO.Compression.FileSystem assembly in your project, you can access three extension methods (from the ZipFileExtensions class) for the ZipArchive class: CreateEntryFromFile, CreateEntryFromFile, and ExtractToDirectory. These extension methods enable you to compress and decompress the contents of the entry to a file.

The System.IO.Compression.FileSystem assembly is not available for Windows Store apps.

In Windows Store apps, you can compress and decompress files by using the DeflateStream or GZipStream class, or you can use the Windows Runtime types Compressor and Decompressor.

Here is the quick sample that would help you to understand how to use ZipArchive class. Code is self explanatory – hope that helps. There are three methods ZipFiles – zip all files in a folder, ExtractFile – to extract files with specificname, ExtractFiles – extract multiple files.

Please go through the below code snippet. If you need additional information: visit MSDN Ref on System.IO.Compression, and in later posts we might discuss about the ZipFile class in more detail.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using System.IO.Compression;
using System.IO;

namespace ConsoleApp01
{
    class Program
    {
        static void Main(string[] args)
        {
            string targetZip = AppDomain.CurrentDomain.BaseDirectory + "\" + System.Guid.NewGuid().ToString() + ".zip";

            string sourceFolder = AppDomain.CurrentDomain.BaseDirectory + "\Sample01" ; //We are going to zip the whole contents of the folder. 

            Console.WriteLine(String.Format("Now Archiving the folder/file {0}, to target zip:{1} ", sourceFolder, targetZip));

            //Zipping the folder 
            ZipFiles(sourceFolder, targetZip);



            string extractFolder = AppDomain.CurrentDomain.BaseDirectory + "\" + Path.GetFileNameWithoutExtension(targetZip);

            Console.WriteLine(String.Format("Now Extracting the file {0}, to location:{1} ", targetZip, extractFolder));

            //Extract the entire Zip file 
            ExtractFiles(targetZip, extractFolder);



            //Extract files based on search pattern such as *.txt
            string extractFolder2 = AppDomain.CurrentDomain.BaseDirectory + "\" + Path.GetFileNameWithoutExtension(targetZip) + "12";

            Console.WriteLine(String.Format("Now Extracting the selected file(s) {0}, to location:{1} ", targetZip, extractFolder2));
            
            //Extract the entire Zip file 
            ExtractFiles(targetZip, extractFolder2, "*.txt");

            Console.WriteLine("Press any key to exit");

            Console.ReadKey();
        }

        /// <summary>
        /// Zips the files from the source folder - for now single level - assuming that we will be zipping all the files in a folder. 
        /// not the child folders and files in it, we will ignore it.
        /// </summary>
        /// <param name="sourceFilesFolderPath">The source files folder path.</param>
        /// <param name="targetZipFilePath">The target zip file path.</param>
        /// <param name="searchPattern">The search pattern.</param>
        public static void ZipFiles(string sourceFilesFolderPath, string targetZipFilePath, string searchPattern = "")
        {
            //if Source Directory exists. 
            if (Directory.Exists(sourceFilesFolderPath))
            {
                using (FileStream zipToOpen = new FileStream(targetZipFilePath, FileMode.OpenOrCreate))
                {
                    //Open Archieve for update
                    using (ZipArchive archive = new ZipArchive(zipToOpen, ZipArchiveMode.Update))
                    {
                        //Getting directory info
                        DirectoryInfo dInfo = new DirectoryInfo(sourceFilesFolderPath);


                        //Getting all files list in the folder 
                        FileInfo[] filesList = dInfo.GetFiles(searchPattern);

                        if (String.IsNullOrEmpty(searchPattern)) //fail safe to retrieve all
                            filesList = dInfo.GetFiles();

                        if (filesList != null && filesList.Length > 0)
                        {
                            //Creating archieve entry for each file in the folder 
                            foreach (FileInfo file in filesList)
                            {
                                archive.CreateEntryFromFile(file.FullName, file.Name);
                            }
                        }


                    }

                }
            }
            else
            {
                throw new DirectoryNotFoundException(String.Format("Source folder: {0} not found",sourceFilesFolderPath);
            }

        }




        /// <summary>
        /// Extracts the files.
        /// </summary>
        /// <param name="sourceZipPath">The source zip path.</param>
        /// <param name="targetExtractPath">The target extract path.</param>
        /// <param name="conditionalExtractPattern">The conditional extract pattern.(OPTIONAL)</param>
        public static void ExtractFiles(string sourceZipPath, string targetExtractPath, string conditionalExtractPattern = "")
        {
            string zipPath      = sourceZipPath;  //Source Zip File 
            string extractPath  = targetExtractPath; //Path to Extract

            if (!Directory.Exists(targetExtractPath))
            {
                Directory.CreateDirectory(targetExtractPath);
            }

            using (ZipArchive archive = ZipFile.OpenRead(zipPath))
            {

                //STEP 1
                foreach (ZipArchiveEntry entry in archive.Entries)
                {
                    //Conditional extract
                    if (!String.IsNullOrEmpty(conditionalExtractPattern))
                    {
                        if (entry.FullName.EndsWith(".txt", StringComparison.OrdinalIgnoreCase))
                        {
                            entry.ExtractToFile(Path.Combine(extractPath, entry.FullName),true);
                        }
                    }
                    else // extract all..
                    {
                        entry.ExtractToFile(Path.Combine(extractPath, entry.FullName),true);
                    }

                    
                }

                //Or EXTRACT ALL USING 

                //STEP 2
                //archive.ExtractToDirectory(targetExtractPath);

            } 

        }




        /// <summary>
        /// Extracts the file.
        /// </summary>
        /// <param name="sourceZipPath">The source zip path.</param>
        /// <param name="targetExtractPath">The target extract path.</param>
        /// <param name="extractFileName">Name of the extract file.</param>
        public static void ExtractFile(string sourceZipPath, string targetExtractPath, string extractFileName)
        {
            string zipPath = sourceZipPath;  //Source Zip File 
            string extractPath = targetExtractPath; //Path to Extract

            using (ZipArchive archive = ZipFile.OpenRead(zipPath))
            {
                //STEP 1
                foreach (ZipArchiveEntry entry in archive.Entries)
                {
                    //Conditional extract
                    if (!String.IsNullOrEmpty(extractFileName))
                    {
                        //Extract the file.
                        if (entry.FullName.EndsWith(extractFileName, StringComparison.OrdinalIgnoreCase))
                        {
                            entry.ExtractToFile(Path.Combine(extractPath, entry.FullName), true);
                        }
                    }

                }

            }

        }

    
    }
}


Visual Studio 2012 RTM available for download

August 16, 2012 .NET, .NET Framework, ADO.NET, All, ASP.NET, ASP.NET MVC, Azure Tools, Microsoft, Silverlight, VB.NET, VisualStudio, VS2012, WCF, Web Services, Windows, WinForms, WPF, WWF No comments

Microsoft has released Visual Studio 2012 RTM for MSDN subscribers on 15th AUG 2012. MSDN Subscribers can download it from MSDN here, logging in with your msdn credentials.

image

Those who doesn’t have MSDN subscription can download trial versions from below links from Microsoft Download Center

Download Microsoft Visual Studio Ultimate 2012

There are two types of installers

1. Web Installer (vs_ultimate.exe): – which will download all necessary packages from the download source location before installation.

2. Download a DVD5 ISO image (VS2012_ULT_ENU.iso): you can use it for offline installation. The ISO image contains all the necessary software’s for the installation. You can download the ISO image directly and install it.

Associated download packages:

Download Microsoft Visual Studio 2012 SDK

Download Microsoft Visual Studio 2012 Visualization & Modeling SDK

Download Microsoft Visual Studio Test Professional 2012

Visual Studio 2012 RTMd

August 1, 2012 .NET, .NET Framework, All, ASP.NET, ASP.NET MVC, C#.NET, Microsoft, Microsoft SDKs, Silverlight, VB.NET, VisualStudio, VS2012, WCF, Windows, Windows Phone, Windows Phone Development, Windows Phone SDK, WPF, WWF No comments

Microsoft has announced the RTM(Release to manufacture) of Visual Studio 2012.

For MSDN Subscribers, the bits will be available for download on August 15th. Visual Studio Professional, Premium, Test Professional, and Ultimate with MSDN Subscribers can also sign up for a free, one year developer account for Windows Store today, with Windows Phone developer accounts coming soon.

Microsoft is planning an exciting launch even on September 12th visit http://visualstudiolaunch.com for more details.

Quick comparison sheet of Visual Studio 2012 editions from Microsoft (view comparison)

image

Sources:

http://channel9.msdn.com/posts/Visual-Studio-2012-RTM

http://www.microsoft.com/visualstudio/11/en-us/products/compare

http://blogs.msdn.com/b/somasegar/archive/2012/08/01/visual-studio-2012-and-net-4-5-complete.aspx

http://blogs.technet.com/b/serverandtools/archive/2012/08/01/platform-delivered-microsoft-visual-studio-2012-and-windows-server-2012-released-to-manufacturing-rtm.aspx

 

Visual Studio 2012 RC(Release Candidate) is released

June 1, 2012 .NET, .NET Framework, All, ASP.NET, ASP.NET MVC, C#.NET, Microsoft, VB.NET, VisualStudio, VS11, VS2012, WCF, WPF No comments

Microsoft has released Visual Studio 2012 RC  and is available for download through MSDN as well.

Visual Studio Ultimate 2012 RC is the state-of-the-art development solution that empowers teams of all sizes to design and create compelling applications to delight users. You can use flexible agile planning tools—like capacity planning, taskboards, and backlog management—to enable incremental development techniques and agile methodologies, at your own pace. Use advanced modeling, discovery, and architecture tools to describe your system and help ensure that your architecture vision is preserved in the implementation. Bring development and operation teams together by using IntelliTrace in production, Operations Manager Connector, and Preemptive Analytics. Improve quality and reduce time to resolution by generating actionable bugs from deployed software, and effectively partner with the operation staff to provide data that gives developers greater insight into production issues.

 

Read these blogs for more details

http://blogs.msdn.com/b/jasonz/archive/2012/05/31/announcing-the-release-candidate-rc-of-visual-studio-2012-and-net-framework-4-5.aspx

http://www.hanselman.com/blog/VisualStudio2012RCIsReleasedTheBigWebRollup.aspx 

http://blogs.msdn.com/b/visualstudio/archive/2012/05/31/visual-studio-2012-rc-available-now.aspx 

 

Download:

Microsoft Visual Studio Professional 2012 RC

Microsoft Visual Studio Premium 2012 RC

Microsoft Visual Studio Ultimate 2012 RC

Microsoft Visual Studio Test Professional 2012 RC 

Microsoft Visual Studio Team Foundation Server 2012 RC

Microsoft Visual Studio Team Foundation Server Express 2012 RC 

ASP.NET MVC 4 Release Candidate for Visual Studio 2010 SP1 and Visual Web Developer 2010 SP1

 

Courtesy: Microsoft Download Center