What's New in the .NET Framework 4

What's New in the .NET Framework 4

This topic contains information about key features and improvements in the .NET Framework version 4. This topic does not provide comprehensive information about all new features and is subject to change.
The .NET Framework 4 introduces an improved security model. For more information, see Security Changes in the .NET Framework 4.
Other new features and improvements in the .NET Framework 4 are described in the following sections:

• Application Compatibility and Deployment
• Core New Features and Improvements
• Managed Extensibility Framework
• Parallel Computing
• Networking
• Web
• Client
• Data
• Windows Communication Foundation
• Windows Workflow Foundation

Application Compatibility and Deployment

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The .NET Framework 4 is highly compatible with applications that are built with earlier .NET Framework versions, except for some changes that were made to improve security, standards compliance, correctness, reliability, and performance.

The .NET Framework 4 does not automatically use its version of the common language runtime to run applications that are built with earlier versions of the .NET Framework. To run older applications with .NET Framework 4, you must compile your application with the target .NET Framework version specified in the properties for your project in Visual Studio, or you can specify the supported runtime with the Element in an application configuration file.

If your application or component does not work after .NET Framework 4 is installed, please submit a bug on the Microsoft Connect Web site. You can test compatibility as described in the .NET Framework 4 Application Compatibility topic and learn about new features by using the Visual Studio 2010 and .NET Framework 4 Walkthroughs. For additional information and known migration issues, visit the .NET Framework Compatibility blog. 

The following sections describe deployment improvements.

Client Profile

The .NET Framework 4 Client Profile supports more platforms than in previous versions and provides a fast deployment experience for your applications. Several new project templates now target the Client Profile by default. For more information, see .NET Framework Client Profile.

In-Process Side-by-Side Execution

This feature enables an application to load and start multiple versions of the .NET Framework in the same process. For example, you can run applications that load add-ins (or components) that are based on the .NET Framework 2.0 SP1 and add-ins that are based on the .NET Framework 4 in the same process. Older components continue to use the older .NET Framework version, and new components use the new .NET Framework version. For more information, see In-Process Side-by-Side Execution.
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Core New Features and Improvements

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The following sections describe new features and improvements provided by the common language runtime and the base class libraries.

Diagnostics and Performance

Earlier versions of the .NET Framework provided no way to determine whether a particular application domain was affecting other application domains, because the operating system APIs and tools, such as the Windows Task Manager, were precise only to the process level. Starting with the .NET Framework 4, you can get processor usage and memory usage estimates per application domain.
You can monitor CPU and memory usage of individual application domains. Application domain resource monitoring is available through the managed and native hosting APIs and event tracing for Windows (ETW). When this feature has been enabled, it collects statistics on all application domains in the process for the life of the process. See the new AppDomain.MonitoringIsEnabled property.
You can now access the ETW events for diagnostic purposes to improve performance. For more information, see CLR ETW Events and Controlling .NET Framework Logging. Also see Performance Counters and In-Process Side-By-Side Applications.
The System.Runtime.ExceptionServices.HandleProcessCorruptedStateExceptionsAttribute attribute enables managed code to handle exceptions that indicate corrupted process state.

Garbage Collection

The .NET Framework 4 provides background garbage collection. This feature replaces concurrent garbage collection in previous versions and provides better performance. For more information, see Fundamentals of Garbage Collection.

Code Contracts

Code contracts let you specify contractual information that is not represented by a method's or type's signature alone. The new System.Diagnostics.Contracts namespace contains classes that provide a language-neutral way to express coding assumptions in the form of preconditions, postconditions, and object invariants. The contracts improve testing with run-time checking, enable static contract verification, and support documentation generation. For more information, see Code Contracts.

Design-Time-Only Interop Assemblies

You no longer have to ship primary interop assemblies (PIAs) to deploy applications that interoperate with COM objects. In the .NET Framework 4, compilers can embed type information from interop assemblies, selecting only the types that an application (for example, an add-in) actually uses. Type safety is ensured by the common language runtime. See Using COM Types in Managed Code and Walkthrough: Embedding Type Information from Microsoft Office Assemblies (C# and Visual Basic).

Dynamic Language Runtime

The dynamic language runtime (DLR) is a new runtime environment that adds a set of services for dynamic languages to the CLR. The DLR makes it easier to develop dynamic languages to run on the .NET Framework and to add dynamic features to statically typed languages. To support the DLR, the new System.Dynamic namespace is added to the .NET Framework.
The expression trees are extended with new types that represent control flow, for example, System.Linq.Expressions.LoopExpression and System.Linq.Expressions.TryExpression. These new types are used by the dynamic language runtime (DLR) and not used by LINQ.
In addition, several new classes that support the .NET Framework infrastructure are added to the System.Runtime.CompilerServices namespace. For more information, see Dynamic Language Runtime Overview.

Covariance and Contravariance

Several generic interfaces and delegates now support covariance and contravariance. For more information, see Covariance and Contravariance in Generics.

BigInteger and Complex Numbers

The new System.Numerics.BigInteger structure is an arbitrary-precision integer data type that supports all the standard integer operations, including bit manipulation. It can be used from any .NET Framework language. In addition, some of the new .NET Framework languages (such as F# and IronPython) have built-in support for this structure.
The new System.Numerics.Complex structure represents a complex number that supports arithmetic and trigonometric operations with complex numbers.

Tuples

The .NET Framework 4 provides the System.Tuple class for creating tuple objects that contain structured data. It also provides generic tuple classes to support tuples that have from one to eight components (that is, singletons through octuples). To support tuple objects that have nine or more components, there is a generic tuple class with seven type parameters and an eighth parameter of any tuple type. 

File System Enumeration Improvements

New file enumeration methods improve the performance of applications that access large file directories or that iterate through the lines in large files. For more information, see How to: Enumerate Directories and Files.

Memory-Mapped Files

The .NET Framework now supports memory-mapped files. You can use memory-mapped files to edit very large files and to create shared memory for interprocess communication.

64-Bit Operating Systems and Processes

You can identify 64-bit operating systems and processes with the Environment.Is64BitOperatingSystem and Environment.Is64BitProcess properties.
You can specify a 32-bit or 64-bit view of the registry with the Microsoft.Win32.RegistryView enumeration when you open base keys.

Other New Features

The following list describes additional new capabilities, improvements, and conveniences. Several of these are based on customer suggestions.

• To support culture-sensitive formatting, the System.TimeSpan structure includes new overloads of the ToString, Parse, and TryParse methods, as well as new ParseExact and TryParseExact methods.
• The new String.IsNullOrWhiteSpace method indicates whether a string is null, empty, or consists only of white-space characters. New overloads have been added to the String.Concat and String.Join methods that concatenate members of System.Collections.Generic.IEnumerable(Of T) collections.
• The String.Concat method lets you concatenate each element in an enumerable collection without first converting the elements to strings.
• Two new convenience methods are available: StringBuilder.Clear and Stopwatch.Restart.
• The new Enum.HasFlag method determines whether one or more bit fields or flags are set in an enumeration value. The Enum.TryParse method returns a Boolean value that indicates whether a string or integer value could be successfully parsed.
• The System.Environment.SpecialFolder enumeration contains several new folders.
• You can now easily copy one stream into another with the CopyTo method in classes that inherit from the System.IO.Stream class.
• New Path.Combine method overloads enable you to combine file paths.
• The new System.IObservable(Of T) and System.IObserver(Of T) interfaces provide a generalized mechanism for push-based notifications.
• The System.IntPtr and System.UIntPtr classes now include support for the addition and subtraction operators.
• You can now enable lazy initialization for any custom type by wrapping the type inside a System.Lazy(Of T) class.
• The new System.Collections.Generic.SortedSet(Of T) class provides a self-balancing tree that maintains data in sorted order after insertions, deletions, and searches. This class implements the new System.Collections.Generic.ISet(Of T) interface.
• The compression algorithms for the System.IO.Compression.DeflateStream and System.IO.Compression.GZipStream classes have improved so that data that is already compressed is no longer inflated. Also, the 4-gigabyte size restriction for compressing streams has been removed.
• The new Monitor.Enter(Object, Boolean) method overload takes a Boolean reference and atomically sets it to true only if the monitor is successfully entered.
• You can use the Thread.Yield method to have the calling thread yield execution to another thread that is ready to run on the current processor.
• The System.Guid structure now contains the TryParse and TryParseExact methods.
• The new Microsoft.Win32.RegistryOptions enumeration lets you specify a volatile registry key that does not persist after the computer restarts.
• Registry keys are no longer restricted to a maximum length of 255 characters.

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Managed Extensibility Framework

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The Managed Extensibility Framework (MEF) is a new library in the .NET Framework 4 that helps you build extensible and composable applications. MEF enables you to specify points where an application can be extended, to expose services to offer to other extensible applications and to create parts for consumption by extensible applications. It also enables easy discoverability of available parts based on metadata, without the need to load the assemblies for the parts. For more information, see Managed Extensibility Framework. For a list of the MEF types, see the System.ComponentModel.Composition namespace.

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Parallel Computing

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The .NET Framework 4 introduces a new programming model for writing multithreaded and asynchronous code that greatly simplifies the work of application and library developers. The new model enables developers to write efficient, fine-grained, and scalable parallel code in a natural idiom without having to work directly with threads or the thread pool. The new System.Threading.Tasks namespace and other related types support this new model. Parallel LINQ (PLINQ), which is a parallel implementation of LINQ to Objects, enables similar functionality through declarative syntax. For more information, see Parallel Programming in the .NET Framework.

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Networking

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Networking improvements include the following:

• Security improvements for Windows authentication in several classes, including System.Net.HttpWebRequest, System.Net.HttpListener, System.Net.Mail.SmtpClient, System.Net.Security.SslStream, and System.Net.Security.NegotiateStream. Extended protection is available for applications on Windows 7 and Windows Server 2008 R2. For more information, see Integrated Windows Authentication with Extended Protection.
• Support for Network Address Translation (NAT) traversal using IPv6 and Teredo. For more information, see NAT Traversal using IPv6 and Teredo.
• New networking performance counters that provide information about HttpWebRequest objects. For more information, see Networking Performance Counters.
• In the System.Net.HttpWebRequest class, support for using large byte range headers (64-bit ranges) with new overloads for the AddRange method. New properties on the System.Net.HttpWebRequest class allow an application to set many HTTP headers. You can use the Host property to set the Host header value in an HTTP request that is independent from the request URI.
• Secure Sockets Layer (SSL) support for the System.Net.Mail.SmtpClient and related classes.
• Improved support for mail headers in the System.Net.Mail.MailMessage class.
• Support for a null cipher for use in encryption. You can specify the encryption policy by using the System.Net.ServicePointManager class and the EncryptionPolicy property. Constructors for the System.Net.Security.SslStream class now take a System.Net.Security.EncryptionPolicy class as a parameter.
• Credentials for password-based authentication schemes such as basic, digest, NTLM, and Kerberos authentication in the System.Net.NetworkCredential class. To improved security, passwords may now be treated as System.Security.SecureString instances rather than System.String instances.
• Ability to specify how a URI with percent-encoded values is converted and normalized in the System.Uri and System.Net.HttpListener classes. For more information, see the System.Net.Configuration.HttpListenerElement, System.Configuration.SchemeSettingElement, System.Configuration.SchemeSettingElementCollection, and System.Configuration.UriSection classes.

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Web

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ASP.NET version 4 introduces new features in the following areas:

• Core services, including a new API that lets you extend caching, support for compression for session-state data, and a new application preload manager (autostart feature).
• Web Forms, including more integrated support for ASP.NET routing, enhanced support for Web standards, updated browser support, new features for data controls, and new features for view state management.
• Web Forms controls, including a new Chart control.
• MVC, including new helper methods for views, support for partitioned MVC applications, and asynchronous controllers.
• Dynamic Data, including support for existing Web applications, support for many-to-many relationships and inheritance, new field templates and attributes, and enhanced data filtering.
• Microsoft Ajax, including additional support for client-based Ajax applications in the Microsoft Ajax Library.
• Visual Web Developer, including improved IntelliSense for JScript, new auto-complete snippets for HTML and ASP.NET markup, and enhanced CSS compatibility.
• Deployment, including new tools for automating typical deployment tasks.
• Multi-targeting, including better filtering for features that are not available in the target version of the .NET Framework.

For more information about these features, see What's New in ASP.NET 4 and Visual Web Developer.

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Client

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Windows Presentation Foundation

In the .NET Framework 4, Windows Presentation Foundation (WPF) contains changes and improvements in many areas, including controls, graphics, and XAML. For more information, see What's New in WPF Version 4.
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Data

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ADO.NET

ADO.NET provides new features for the Entity Framework, including persistence-ignorant objects, functions in LINQ queries, and customized object layer code generation. For more information, see What's New in ADO.NET.

Dynamic Data

For ASP.NET 4, Dynamic Data has been enhanced to give you even more power for quickly building data-driven Web sites. This includes the following:

• Automatic validation that is based on constraints that are defined in the data model.
• The ability to easily change the markup that is generated for fields in the GridView and DetailsView controls by using field templates that are part of a Dynamic Data project.

For more information, see What's New in ASP.NET 4 and Visual Web Developer.

WCF Data Services

ADO.NET Data Service has been renamed to WCF Data Services, and has the following new features

• Data binding.
• Counting entities in an entity set.
• Server-driven paging.
• Query projections.
• Custom data service providers.
• Streaming of binary resources.

For more information, see What's New in WCF Data Services.
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Windows Communication Foundation

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Windows Communication Foundation (WCF) provides the following improvements:

• Configuration-based Activation: Removes the requirement for having an .svc file.
• System.Web.Routing Integration: Allows you to have more control over your service's URL (extensionless URLs).
• Multiple IIS Site Bindings Support: Allows you to have multiple base addresses with the same protocol on the same Web site.
• Routing Service: Allows you to route messages based on content.
• Support for WS-Discovery: Allows you to create and search for discoverable services.
• Standard Endpoints: Predefined endpoints that allow you to specify only certain properties.
• Workflow Services: Integrates WCF and WF by providing activities to send and receive messages, the ability to correlate messages based on content, and a workflow service host.
• WCF REST features:
  
  • Web HTTP Caching: Allows caching of Web HTTP service responses.
  • Web HTTP Formats Support: Allows you to dynamically determine the best format for a service operation to respond in.
  • Web HTTP Services Help Page: Provides an automatic help page for Web HTTP services, similar to the WCF service help page.
  • Web HTTP Error Handling: Allows Web HTTP Services to return error information in the same format as the operation.
  • Web HTTP Cross-Domain JavaScript Support: Allows use of JSONP.
• Simplified Configuration: Reduces the amount of configuration a service requires

For more information, see What's New in Windows Communication Foundation.

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Windows Workflow Foundation

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Windows Workflow Foundation provides improvements in the following areas:

• Improved Workflow Activity Model: The Activity class provides the base abstraction of workflow behavior.
• Rich Composite Activity Options: Workflows benefit from new flow-control activities that model traditional flow-control structures, such as Flowchart, TryCatch, and Switch.
• Expanded Built-In Activity Library: New features of the activity library include new flow-control activities, activities for manipulating member data, and activities for controlling transactions.
• Explicit Activity Data Model: New options for storing or moving data include variable and directional arguments.
• Enhanced Hosting, Persistence, and Tracking Options: Hosting enhancements include more options for running workflows, explicit persistence using the Persist activity, persisting without unloading, preventing persistence using no-persist zones, using ambient transactions from the host, recording tracking information to the event log, and resuming pending workflows using Bookmark.
• Easier ability to extend the WF designer: The new WF Designer is built on Windows Presentation Foundation (WPF) and provides an easier model to use when rehosting the WF Designer outside of Visual Studio.

Learn Web Services

http://www.developers.net/intelisnshowcase/view/1086

Writing Excel file with data set

here is the way by which we can create a excel file. here i hvae use a data set in which all the values are present which i want to write in the excel sheet.

first of all the column head is stored in an array and the value is present in the data set.  You just need to add the COM reference in the application using the Microsoft 12.0 Excel object library.

Use the name space to create the excel object.

                                           

string[] sExcelRow ={ "A", "B", "C", "D", "E", "F", "G", "H", "I",}

 Microsoft.Office.Interop.Excel.Sheets sheets;                 

                  Microsoft.Office.Interop.Excel.Workbooks workbooks = exc.Workbooks;

                  Microsoft.Office.Interop.Excel._Workbook workbook = workbooks.Add(Microsoft.Office.Interop.Excel.XlWBATemplate.xlWBATWorksheet);

                  sheets = workbook.Worksheets;

                  Microsoft.Office.Interop.Excel._Worksheet worksheet;

                  worksheet = (Microsoft.Office.Interop.Excel.Worksheet)sheets.get_Item(1);

   for (int i = 0; i <>

                  {

                      worksheet.get_Range(sExcelRow[i] + 1,  sExcelRow[i] + 1).Value2 = sExcelCol[i].ToString();

                      worksheet.get_Range(sExcelRow[i] + 1, sExcelRow[i] + 1).Font.Bold = true;

                      worksheet.get_Range(sExcelRow[i] + 1, sExcelRow[i] + 1).HorizontalAlignment = Microsoft.Office.Interop.Excel.Constants.xlCenter;

                      worksheet.get_Range(sExcelRow[i] + 1, sExcelRow[i] + 1).EntireColumn.AutoFit();

  for (int j = 0; j <>

                  {

                      string strFieldStatus = string.Empty;

                      for (int l = 0; l <>

                      {

                      

                              worksheet.get_Range(sExcelRow[l] + x, sExcelRow[l] + x).Value2 = System.IO.Path.GetFileName(Convert.ToString(ldsUser1.Tables[0].Rows[j][l + 1]));

                              worksheet.get_Range(sExcelRow[l] + x, sExcelRow[l] + x).EntireColumn.AutoFit();

                              worksheet.get_Range(sExcelRow[l] + x, sExcelRow[l] + x).EntireColumn.NumberFormat = "@";

                        }

workbook.SaveAs(strFile1, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal, Type.Missing, Type.Missing, false, false, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlShared, false, false, Type.Missing, Type.Missing, Type.Missing);

 workbook.Close(true, Type.Missing, Type.Missing);

webservices in asp.net

Introduction

Microsoft .NET marketing has created a huge hype about its Web Services. This is the first of two articles on Web Services. Here we will create a .NET Web Service using C#. We will look closely at the Discovery protocol, UDDI, and the future of the Web Services. In the next article, we will concentrate on consuming existing Web Services on multiple platforms (i.e., Web, WAP-enabled mobile phones, and windows applications).

Why do we need Web Services?

After buying something over the Internet, you may have wondered about the delivery status. Calling the delivery company consumes your time, and it's also not a value-added activity for the delivery company. To eliminate this scenario the delivery company needs to expose the delivery information without compromising its security. Enterprise security architecture can be very sophisticated. What if we can just use port 80 (the Web server port) and expose the information through the Web server? Still, we have to build a whole new Web application to extract data from the core business applications. This will cost the delivery company money. All the company wants is to expose the delivery status and concentrate on its core business. This is where Web Services come in.

What is a Web Service?

Web Services are a very general model for building applications and can be implemented for any operation system that supports communication over the Internet. Web Services use the best of component-based development and the Web. Component-base object models like Distributed Component Object Model (DCOM), Remote Method Invocation (RMI), and Internet Inter-Orb Protocol (IIOP) have been around for some time. Unfortunately all these models depend on an object-model-specific protocol. Web Services extend these models a bit further to communicate with the Simple Object Access Protocol (SOAP) and Extensible Markup Language (XML) to eradicate the object-model-specific protocol barrier (see Figure 1).

Web Services basically uses Hypertext Transfer Protocol (HTTP) and SOAP to make business data available on the Web. It exposes the business objects (COM objects, Java Beans, etc.) to SOAP calls over HTTP and executes remote function calls. The Web Service consumers are able to invoke method calls on remote objects by using SOAP and HTTP over the Web.

Figure 1. SOAP calls are remote function calls that invoke method executions on Web Service components at Location B. The output is rendered as XML and passed back to the user at Location A.

How is the user at Location A aware of the semantics of the Web Service at Location B? This question is answered by conforming to a common standard. Service Description Language (SDL), SOAP Contract Language (SCL) and Network Accessible Specification Language (NASSL) are some XML-like languages built for this purpose. However, IBM and Microsoft recently agreed on the Web Service Description Language (WSDL) as the Web Service standard.

The structure of the Web Service components is exposed using this Web Service Description Language. WSDL 1.1 is a XML document describing the attributes and interfaces of the Web Service. The new specification is available at msdn.microsoft.com/xml/general/wsdl.asp.

The task ahead

The best way to learn about Web Services is to create one. We all are familiar with stock quote services. The NASDAQ, Dow Jones, and Australian Stock Exchange are famous examples. All of them provide an interface to enter a company code and receive the latest stock price. We will try to replicate the same functionality.

The input parameters for our securities Web service will be a company code. The Web service will extract the price feed by executing middle-tier business logic functions. The business logic functions are kept to a bare minimum to concentrate on the Web service features.

Tools to create a Web Service

The core software component to implement this application will be MS .NET Framework SDK, which is currently in beta. You can download a version from Microsoft. I used Windows 2000 Advance Server on a Pentium III with 300 MB of RAM.

The preferred Integration Development Environment (IDE) to create Web Services is Visual Studio .NET. However, you can easily use any text editor (WordPad, Notepad, Visual Studio 6.0) to create a Web Service file.

I assume you are familiar with the following concepts:

* Basic knowledge of .NET platform
* Basic knowledge of C#
* Basic knowledge of object-oriented concepts

Creating a Web Service

We are going to use C# to create a Web Service called "SecurityWebService." A Web Service file will have an .ASMX file extension. (as opposed to an .ASPX file extension of a ASP.NET file). The first line of the file will look like

<%@ WebService Language="C#" class="SecurityWebService" %>

This line will instruct the compiler to run on Web Service mode and the name of the C# class. We also need to access the Web Service namespace. It is also a good practice to add a reference to the System namespace.

using System;
using System.Web.Services;

The SecurityWebService class should inherit the functionality of the Web Services class. Therefore, we put the following line of code:

public class SecurityWebService : WebService

Now we can use our object-oriented programming skills to build a class. C# classes are very similar to C++ or Java classes. It will be a walk in the park to create a C# class for anyone with either language-coding skills.

Dot-net Web Services are intelligent enough to cast basic data types. Therefore, if we return "int," "float," or "string" data types, it can convert them to standard XML output. Unfortunately, in most cases we need get a collection of data regarding a single entity. Let's take an example.

Our SecurityWebService stock quotes service requires the user to enter a company code, and it will deliver the full company name and the current stock price. Therefore, we have three pieces of information for a single company:

1. Company code (data type - string)
2. Company name (data type - string)
3. Price (data type - Double)

We need to extract all this data when we are referring to a single stock quote. There are several ways of doing this. The best way could be to bundle them in an enumerated data type. We can use "structs" in C# to do this, which is very similar to C++ structs.

public struct SecurityInfo
{
public string Code;
public string CompanyName;
public double Price;
}

Now we have all the building blocks to create our Web Service. Therefore, our code will look like.

<%@ WebService Language="C#" class="SecurityWebService" %>

using System;
using System.Web.Services;

public struct SecurityInfo
{
public string Code;
public string CompanyName;
public double Price;
}

public class SecurityWebService : WebService
{
private SecurityInfo Security;

public SecurityWebService()
{
Security.Code = "";
Security.CompanyName = "";
Security.Price = 0;
}

private void AssignValues(string Code)
{
// This is where you use your business components.
// Method calls on Business components are used to populate the data.
// For demonstration purposes, I will add a string to the Code and
// use a random number generator to create the price feed.

Security.Code = Code;
Security.CompanyName = Code + " Pty Ltd";
Random RandomNumber = new System.Random();
Security.Price = double.Parse(new System.Random(RandomNumber.Next(1,10)).NextDouble().ToString("##.##"));
}

[WebMethod(Description="This method call will get the company name and the price for a given security code.",EnableSession=false)]
public SecurityInfo GetSecurityInfo(string Code)
{
AssignValues(Code);
SecurityInfo SecurityDetails = new SecurityInfo();
SecurityDetails.Code = Security.Code;
SecurityDetails.CompanyName = Security.CompanyName;
SecurityDetails.Price = Security.Price;
return SecurityDetails;
}

}

Remember, this Web Service can be accessed through HTTP for any use. We may be referring to sensitive business data in the code and wouldn't want it to fall into the wrong hands. The solution is to protect the business logic function and only have access to the presentation functions. This is achieved by using the keyword "[Web Method]" in C#. Let's look at the function headers of our code.

[WebMethod(Description="This......",EnableSession=false)]
public SecurityInfo GetSecurityInfo(string Code)

This function is exposed to the public. The "description" tag can be used to describe the Web Service functionality. Since we will not be storing any session data, we will disable the session state.

private void AssignValues(string Code)

This is a business logic function that should not be publicly available. We do not want our sensitive business information publicly available on the Web. (Note:- Even if you change the "private" keyword to "public," it will still not be publicly available. You guessed it, the keyword "[Web Method]" is not used.)

We can use the business logic in this function to get the newest stock price quote. For the purpose of this article I have added some text to the company code to create the company name. The price value is generated using a random number generator.

We may save this file as "SampleService.asmx" under an Internet Information Service (IIS)-controlled directory. I have saved it under a virtual directory called "/work/aspx." I'll bring it up on a Web browser.

This is a Web page rendered by the .NET Framework. We did not create this page. (The page is generated automatically by the system. I did not write any code to render it on the browser. This graphic is a by-product of the previous code.) This ready-to-use functionality is quite adequate for a simple Web Service. The presentation of this page can be changed very easily by using ASP.NET pagelets and config.web files. A very good example can be found at http://www.ibuyspy.com/store/InstantOrder.asmx.

Notice a link to "SDL Contract." (Even if we are using WSDL, .NET Beta still refers to SDL. Hopefully this will be rectified in the next version). This is the description of the Web Service to create a proxy object. (I will explain this in the next article.) This basically gives an overview of the Web Service and it's public interface. If you look closely, you will only see the "Web-only" methods being illustrated. All the private functions and attributes are not described in the SDL contract. The SDL contract for the SecurityWebService can be found in Appendix A.

# view demo of SecurityWebService

How do we use a Web Service?

Now we can use this Web Service. Let's enter some values to get a bogus price feed.

By clicking the Invoke button a new window will appear with the following XML document

This is how the Web Service releases information. We need to write clients to extract the information from the XML document. Theses clients could be

1. A Web page
2. A console / Windows application
3. A Wireless Markup Language (WML) / WMLScript to interact with mobile phones
4. A Palm / Win CE application to use on Personal Digital Assistants (PDAs).

I will explain this process in the next article.

You can also call the Web Service directly using the HTTP GET method. In this case we will not be going through the above Web page and clicking the Invoke button. The syntax for directly calling the Web Service using HTTP GET is

http://server/webServiceName.asmx/functionName?parameter=parameterValue

Therefore, the call for our Web Service will be

http://localhost/work/aspx/SampleService.asmx/GetSecurityInfo?Code=IBM

This will produce the same result as clicking the Invoke button.

Now we know how to create a Web Service and use it. But the work is half done. How will our clients find our Web Service? Is there any way to search for our Web Service on the Internet? Is there a Web crawler or a Yahoo search engine for Web Services? In order to answer these questions we need to create a "discovery" file for our Web Service.

Creating a Discovery file

Web Service discovery is the process of locating and interrogating Web Service descriptions, which is a preliminary step for accessing a Web Service. It is through the discovery process that Web Service clients learn that a Web Service exists, what its capabilities are, and how to properly interact with it. Discovery file is a XML document with a .DISCO extension. It is not compulsory to create a discovery file for each Web Service. Here is a sample discovery file for our securities Web Service.






We can name this file "SampleService.disco" and save it to the same directory as the Web Service. If we are creating any other Web Services under the "/work/aspx" directory, it is wise to enable "dynamic discovery." Dynamic discovery will scan for all the *.DISCO files in all the subdirectories of "/work/aspx" automatically.





An example of an active discovery file can be found at http://services3.xmethods.net/dotnet/default.disco. By analyzing the discovery file we can find where the Web Services reside in the system. Unfortunately both these methods require you to know the exact URL of the discovery file. If we cannot find the discovery file, we will not be able to locate the Web Services. Universal Description, Discovery, and Integration (UDDI) describes mechanisms to advertise existing Web Services. This technology is still at the infant stage. UDDI is an open, Internet-based specification designed to be the building block that will enable businesses to quickly, easily, and dynamically find and transact business with one another using their preferred applications. A reference site for UDDI is http://uddi.microsoft.com.

There have been a lot of Web Services written by developers. www.xmethods.com is one of the sites that has an index of Web Services. Some developers are building WSDL search engines to find Web Services on the Web.

Deploying a Web Service

Deploying the Web Services from development to staging or production is very simple. Similar to ASP.NET applications, just copy the .ASMX file and the .DISCO files to the appropriate directories, and you are in business.

The future of the Web Services

The future looks bright for the Web Service technology. Microsoft is not alone in the race for Web Service technology. Sun and IBM are very interested. There are SOAP toolkits available for Apache and Java Web servers. I believe Web Services needs a bit of work, especially the Web Service discovery process. It is still very primitive.

On a positive note, Web Services have the potential to introduce new concepts to the Web. One I refer to as "pay per view" architecture. Similar to pay-TV, we can build Web sites that can generate revenue for each request a user sends (as opposed to a flat, monthly subscription). In order to get some data, we can sometimes pay a small fee. Commercially this could be handy for a lot of people.

Examples

* Online newspaper sites can publish a 10-year-old article with a $2 "pay per view" structure.
* Stock market portals can itemize every user portfolio for every single stock quote and build pricing and discount structures.

And the list goes on ...

On a very optimistic note, Web Services can be described as the "plug and play" building blocks of enterprise Business to Business (B2B) Web solutions.

Appendix A

This method call will get the company name and the price for a given security code.

This method call will get the company name and the price for a given security code.












This method call will get the company name and the price for a given security code.

Ajax advantage and Disadvantage

Why use AJAX?

Building a web application that employs AJAX is more difficult than building it the classic way. You need to go to extra lengths to make sure that the user experience is and remains enjoyable, and not plain annoying. With all the hype going around AJAX, a lot of applications that do not have a real need for it have been built. These are toys meant to prove that AJAX is fun, but with little or no use in real-life situations. At the same time, some applications that do not use AJAX are labeled as such. You can find a list of AJAX applications by using a search engine, or directly here.

The decision whether an application would benefit from using AJAX or not is entirely up to the developer. Here are a few hints to help you take the right decision.

The Benefits of AJAX

To help you decide whether AJAX is for you or not, here are some of the advantages it has over classic web development techniques:

1. The interface is much more responsive, as explained before, because only a small part of the page is transferred at a time. The user has the feeling that changes are instantaneous.
2. In a classic web application, when the web server sends a web page to the browser, it can use multiple connection threads to speed up delivery. However, this happens for content only – what is between the tags. All script and CSS files linked in the page's section are transferred using only one connection thread, which diminishes performance. With AJAX, you only have to load the basic scripts and CSS files, and request the rest as content, through multiple connections.
3. Waiting time is reduced – when the visitor submits a form, they no longer have to wait for the entire page to be rebuilt and re-transmitted by the server. Instead, only the relevant content changes, and in non-critical cases, the visitor can still work while the data is being submitted.
4. If a page section encounters an error, other sections are not affected (if not logically linked) and the data already entered by the user is not lost. This way, the application fails graciously, without causing head-aches for the users.
5. Traffic to and from the server is reduced considerably – because you do not have to send the entire page content (CSS, images, static sections), the bandwidth usage is most likely to decrease.

The Disadvantages of AJAX

As with most new web development techniques, AJAX has its critics. There are a couple of disadvantages that need to be considered before considering an AJAX-based solution:

1. Building an AJAX-powered application can increase development time and costs. It is usually considered more difficult than building a classic web application, because of the mixture of technologies and the special concern about everything going smoothly. However, because it is dealing with relatively known technologies, AJAX is not rocket science.
2. Although AJAX relies on existing and mature technologies like Javascript, HTML and CSS, the available frameworks and components still need to completely mature. Tools like the Dojo toolkit or the Rico framework are just a milestone on this long road. More frameworks that target a specific area are likely to come your way. At InterAKT Online, we're also working on an AJAX-based e-commerce platform to be announced soon. We also released a free JavaScript editor for the Eclipse platform, that you can download from our site.
3. Not all concerns regarding security and user privacy have been answered. This fueled a wave of criticism about how safe is the AJAX way of building applications. Earle Castledine points out some of his concerns regarding user privacy in this article from DevX.com.
4. Using AJAX to asynchronously load bits of content into an existing page conflicts with the way we are used to navigate and create bookmarks in modern browsers. Because viewing some part of the page information no longer corresponds to a newly loaded page, the browser history and bookmarks will not be able to restore the exact page state. Also, clicking the Back button in a browser might not have any effect, since the URL was unchanged (even if parts of the page were changed). To overcome these problems you must implement a way to save the current page state so that it can be restored later on, when called from a bookmark or from the browser history.
5. AJAX is not meant to be used in every application. One of the main reasons for this stays in the fact that Google cannot index it. Consider this basic example that Alexandru Costin, the co-founder of InterAKT Online, pointed out: "Suppose you are building an e-commerce site. A complete AJAX application would be a mistake because search engines won't be able to index it. And without a search engine, a site won't be able to sell products." Keeping this in mind, a much better idea than creating complete AJAX applications would be to scatter AJAX features within the application.
6. The biggest concern with AJAX is accessibility. This is because not all browsers (especially older ones) have complete support for JavaScript or the XMLHttpRequest object. Some of the visitors do have browsers with the required features, but they choose or have to turn off JavaScript support. When you design the application you must make sure that a fail-safe solution exists for those users, so it can be accessed by anyone. Further more, the way to access and use the XMLHttpRequest object in Internet Explorer and other browsers is different, which leads to a fork in the code and the need to treat each case separately.
7. The last disadvantage lies in the actual XMLHttpRequest object itself. Due to security constraints, you can only use it to access information from the host that served the initial page. If you need to display information from another server, it is not possible within the AJAX paradigm.

LINQ MOST IMPORTANT FOR U AND ME

Introducing LINQ Tutorial

These reference sites that might help you:

Wikipedia: http://en.wikipedia.org/wiki/Language_integrated_query
CodeProject: http://www.codeproject.com/KB/linq/
LINQ Video: http://windowsclient.net/learn/videos_LINQ.aspx , http://www.asp.net/learn/linq-videos/
LINQ Article by Anders: http://msdn.microsoft.com/en-us/library/bb308959.aspx
LINQ at MSDN: http://msdn.microsoft.com/en-us/library/bb397926.aspx
LINQ Project Home page at MSDN: http://msdn.microsoft.com/en-us/netframework/aa904594.aspx
LINQ FAQ: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=307705&SiteID=1

ScottGu's Blog
# Part 1: Introduction to LINQ to SQL
# Part 2: Defining our Data Model Classes
# Part 3: Querying our Database
# Part 4: Updating our Database
# Part 5: Binding UI using the ASP:LinqDataSource Control
# Part 6: Retrieving Data Using Stored Procedures
# Part 7: Updating our Database using Stored Procedures
# Part 8: Executing Custom SQL Expressions
# Part 9: Using a Custom LINQ Expression with the control)


Step by step...
Introducing LINQ – Part 1
Introducing LINQ – Part 2
Introducing LINQ – Part 3
Introducing LINQ – Part 4
Introducing LINQ – Part 5

Asp.Net Membership: How to change a user's password from an admin account without knowing the current password?

Asp.Net Membership: How to change a user's password from an admin account without knowing the current password?



Like mine, you may also need to change a user's password from an admin account. By default, when you are using ASP.Net authentication and storing the password in the hashed format, you will not be able to see the existing password in its decrypted form. Also, to change a password using the Membership API, you will need to know the existing password. However, here is a simple solution to the problem -

AspNetChangePassword

The idea is, you can reset the password of a user using the following code-

string tempPass = Membership.Provider.ResetPassword("username", string.Empty)

Make sure you have the config that allows you to change password without an answer to the security question. Now, you can invoke the ChangePassword method using this tempPass as the existing pass and your custom password as the new password. Refer to the following line for a compact implementation-

Membership.Provider.ChangePassword("username", Membership.Provider.ResetPassword("username", string.Empty), "custompass")

I believe this will save your time with a similar need.