Wcf services, data access, and other features

5.1 Introduction

Microsoft Windows Communication Foundation ( WCF ) is one of the cardinal engineerings available in.NET Framework 3.0 and ulterior versions. This session briefly introduces an overview of WCF services. The session besides takes a expression at the new informations related controls in ASP.NET 3.5. As organisations grow planetary, there is a strong demand for Web applications to accommodate to planetary audiences and civilizations. This session describes globalisation and besides discusses the support for handiness in ASP.NET 3.5. Finally, the session explains about nomadic applications in ASP.NET 3.5.

5.2 WCF Services

WCF is designed as incorporate programming theoretical account that helps to make distributed applications utilizing assorted.NET engineerings such as utilizing Web services, .NET Remoting, Message Queue ( MSMQ ) , Enterprise Services, and so forth. Through WCF, you can make a individual service that can be exposed as named pipes, HTTP, TCP, and so on.

5.2.1 Making a WCF Service with ASP.NET

ASP.NET and Visual Studio 2008 enable you to make and devour WCF services. The first measure towards this is to specify the service contract.

The stairss to specify a service contract are as follows:

1. Launch Ocular Studio and choose a new Web undertaking of type WCF Service Application. This templet defines a Web undertaking for hosting the WCF service and will make a mention to System.ServiceModel.dll in the undertaking. This assembly contains the WCF categories. The undertaking templet will besides bring forth a default service named Service1.svc and a related contract file named IService1.cs. You can rename these two files suitably. For illustration, you could call the undertaking as TestServices and the service itself as NewService.

The contract file, INewService.cs, is a.NET Framework interface that includes the service property classes for the service category, the operations, and the members. The.svc.cs file is a category implementing this interface. A WCF Service application is automatically configured so that it can be hosted in IIS. It exposes a standard HTTP end point. The & lt ; system.servicemodel & gt ; subdivision of the web.config file describes these scenes.

An illustration of & lt ; system.servicemodel & gt ; subdivision in web.config is shown in Code Snippet 1.

Code Snippet 1

& lt ; system.serviceModel & gt ;

& lt ; services & gt ;

& lt ; service name= '' TestServices.NewService ''

behaviorConfiguration= '' TestServices.NewService '' & gt ;

& lt ; endpoint address= '' '' binding= '' wsHttpBinding ''

contract= '' TestServices.NewService.INewService '' & gt ;

& lt ; individuality & gt ;

& lt ; dns value= '' localhost '' / & gt ;

& lt ; /identity & gt ;

& lt ; /endpoint & gt ;

& lt ; endpoint address= '' mex '' binding= '' mexHttpBinding '' contract= '' IMetadataExchange '' / & gt ;

& lt ; /service & gt ;

& lt ; /services & gt ;

& lt ; behaviours & gt ;

& lt ; serviceBehaviors & gt ;

& lt ; behavior name= '' TestServices.NewServiceBehavior '' & gt ;

& lt ; serviceMetadata httpGetEnabled= '' true '' / & gt ;

& lt ; serviceDebug includeExceptionDetailInFaults= '' false '' / & gt ;

& lt ; /behavior & gt ;

& lt ; /serviceBehaviors & gt ;

& lt ; /behaviors & gt ;

& lt ; /system.serviceModel & gt ;

2. Implement the service contract. To implement the service, you start by specifying the contract via the interface. For illustration, see a scenario where you want to expose methods of a service that work with the Suppliers table in a Shipments database. Make a Supplier category inside ISupplierService.cs and tag it as a DataContract and taging each of its members as DataMember. Code Snippet 2 shows an illustration:

Code Snippet 2

[ DataContract ]

public category Supplier

{

// specify a belongings

[ DataMember ]

public int SupplierCode { get ; set ; }

// define other belongingss

}

The following measure is to specify the methods of your interface in ISupplierService.cs and tag them with the OperationContract property. You need to tag the interface with the ServiceContract property as shown in Code Snippet 3.

Code Snippet 3

[ ServiceContract ]

public interface ISupplierService

{

[ OperationContract ]

Supplier GetSupplier ( int supplierCode ) ;

[ OperationContract ]

Supplier SaveSupplier ( Supplier supplierper ) ;

}

WCF will utilize the interface to expose a service. The service will be configured based on the web.config file.

The service interface is implemented inside the ISupplierService.svc.cs file as shown in Code Snippet 4.

Code Snippet 4

public category SupplierService: ISupplierService

{

confString =

ConfigurationManager.ConnectionStrings [ `` SupplierString '' ] .ToString ( ) ;

public Supplier GetSupplier ( int supplierId )

{

. . .

}

public nothingness Display ( Supplier provider )

{

. . .

}

}

The contract is defined via the ISupplierService interface. The contract is implemented inside the SupplierService.svc file.

5.3.2 Calling or devouring the WCF service

The stairss to configure one or more service end points and host the service in an application are taken attention of by default while executing all the stairss carried out until now. For illustration, an end point is configured via the default HTTP end point set up inside the web.config file and the service is hosted by IIS and ASP.NET.

Now eventually, you can name the WCF service. You need to put a client to name the service. The client could be an ASP.NET Web site, a Windows application, or an application on a different platform.

Assuming that the client is traveling to be an ASP.NET Web site for the current scenario, the stairss to name the service are as follows:

1. Make an ASP.NET Web site.

2. To bring forth a proxy category utilizing Ocular Studio 2008, right-click your Web site and choice Add Service Reference. The Add Service Reference duologue box is displayed as shown in figure 5.2.

This duologue box allows you to specify an reference to your service. The construct of proxy category is similar to that in XML Web services - it is a WCF service client enabling you to work with the service without holding to cover with the inside informations of WCF. You can besides make the placeholder by utilizing the ServiceModel Metadata Utility command-line tool ( Svcutil.exe ) .

3. Stipulate an appropriate namespace in the Namespace box in the duologue box. This namespace will specify the name for the proxy category that will be generated by Ocular Studio.

4. Specify binding and end point information. Actually, the Add ServiceReference duologue box generates the appropriate end point information automatically when you add the service mention. The web.config file will incorporate this information as shown in Code Snippet 5.

Code Snippet 5

& lt ; system.serviceModel & gt ;

& lt ; bindings & gt ;

& lt ; wsHttpBinding & gt ;

& lt ; adhering name= '' WSHttpBinding_ISupplierService '' closeTimeout= '' 00:01:00 ''

openTimeout= '' 00:01:00 '' receiveTimeout= '' 00:10:00 '' sendTimeout= '' 00:01:00 ''

bypassProxyOnLocal= '' false '' transactionFlow= '' false ''

hostNameComparisonMode= '' StrongWildcard '' maxBufferPoolSize= '' 524288 ''

maxReceivedMessageSize= '' 65536 '' messageEncoding= '' Text ''

textEncoding= '' utf-8 '' useDefaultWebProxy= '' true '' allowCookies= '' false '' & gt ;

& lt ; readerQuotas maxDepth= '' 32 '' maxStringContentLength= '' 8192 ''

maxArrayLength= '' 16384 '' maxBytesPerRead= '' 4096 ''

maxNameTableCharCount= '' 16384 '' / & gt ;

& lt ; reliableSession ordered= '' true '' inactivityTimeout= '' 00:10:00 ''

enabled= '' false '' / & gt ;

& lt ; security mode= '' Message '' & gt ;

& lt ; transport clientCredentialType= '' Windows '' proxyCredentialType= '' None ''

realm= '' '' / & gt ;

& lt ; message clientCredentialType= '' Windows '' negotiateServiceCredential= '' true ''

algorithmSuite= '' Default '' establishSecurityContext= '' true '' / & gt ;

& lt ; /security & gt ;

& lt ; /binding & gt ;

& lt ; /wsHttpBinding & gt ;

& lt ; /bindings & gt ;

& lt ; client & gt ;

& lt ; endpoint address= '' hypertext transfer protocol: //localhost:4392/SupplierService.svc ''

binding= '' wsHttpBinding ''

bindingConfiguration= '' WSHttpBinding_ISupplierService ''

contract= '' NwServices.ISupplierService ''

name= '' WSHttpBinding_ISupplierService '' & gt ;

& lt ; individuality & gt ;

& lt ; dns value= '' localhost '' / & gt ;

& lt ; /identity & gt ;

& lt ; /endpoint & gt ;

& lt ; /client & gt ;

& lt ; /system.serviceModel & gt ;

There are two options to pull off and redact the WCF constellation information: you can redact straight in web.config or you can utilize the Service Configuration Editor to pull off your end points. Right-click the web.config file and take Edit Wcf Configuration. This will establish the Service Configuration Editor duologue box.

Finally, you will make a Web page will name the service via the proxy category. Code Snippet 6 shows portion of the codification in the Web page that will instantiate the proxy category and name the service.

Code Snippet 6

. . .

SupplierServices.SupplierServiceClient testSupplier =

new SupplierServices.ShipperServiceClient ( ) ;

SupplierServices.Supplier provider = new SupplierServices.Supplier ( ) ;

provider = testSupplier.GetSupplier ( supplierCode ) ;

5.5 New Data Controls in ASP.NET 3.5

ASP.NET 3.5 defines several new informations related controls including LinqDataSource, EntityDataSource, and ListView.

5.5.1 LinqDataSource

Language-Integrated Query ( LINQ ) is a set of characteristics that adds question capablenesss to.NET linguistic communications such as C # . LINQ enables you to question informations from diverse informations beginnings in an easy mode. The lone status is that these informations beginnings must be LINQ-compatible, which means they must be supported by LINQ. LINQ can be used with SQL, XML files, objects ( such as C # arrays and aggregations ) , and ADO.NET DataSets.

The LinqDataSource is new to ASP.NET 3.5 and Visual Studio 2008. It is used to recover informations from a LINQ information theoretical account. This control enables you to expose informations from a database by utilizing LINQ to SQL. Once you have generated informations categories utilizing the Object/Relational ( O/R ) interior decorator, you can adhere to those categories utilizing the LinqDataSource control.

The ContextTypeName property is used in markup with the LinqDataSource to tie in the database context of your LINQ-based informations.

See a scenario where you have defined a DataContext category named EmpDataContext utilizing Linq to SQL Classes in Visual Studio 2008. The following markup shows how you would link to this category utilizing the LinqDataSource control:

Code Snippet 7

& lt ; asp: LinqDataSource

ID= '' lnqEmp ''

runat= '' waiter ''

ContextTypeName= '' EmpDataContext ''

EnableDelete= '' True ''

EnableInsert= '' True ''

EnableUpdate= '' True ''

OrderBy= '' EmpCode ''

TableName= '' Employees '' & gt ;

& lt ; /asp: LinqDataSource & gt ;

Alternatively of typing the markup shown in Code Snippet 7, you can besides utilize the Configure Data Source ace to tie in the DataContext category with the LinqDataSource control. This can be done utilizing following stairss:

1. Add a LinqDataSource control to the Web page.

2. Snap the smart ticket beside the control.

3. In the context bill of fare that is displayed, choice Configure Data Source. This will expose the Configure Data Source ace as shown in figure 5.3.

Figure 5.3: Configure Data Source Wizard for LinqDataSource

4. Continue with the measure by measure process shown in the Configure Data Source ace.

The LinqDataSource control allows you to specify parametric quantities, to bespeak sorting, enable paging, and more. You can besides specify questions holding Where and OrderBy clauses. The Where clause uses the WhereParameters stand foring a question twine that filters the information on the question twine. You can besides adhere a LinqDataSource control to a data-bound control.

5.5.2 EntityDataSource

The EntityDataSource control is new to the.NET Framework 3.5. The EntityDataSource control enables you to entree informations utilizing the ADO.NET Entity Framework. Users who are familiar with data-bound controls will happen the EntityDataSource control similar to the SqlDataSource, LinqDataSource, and ObjectDataSource controls. The EntityDataSource control enables you to adhere informations in an Entity Data Model ( EDM ) to Web controls on a page. You construct questions utilizing snippings of Entity SQL codification and delegate them to the Where, OrderBy, GroupBy, and Select operators. You can provide parameter values to these operations from page controls, cookies, and other ASP.NET parametric quantity objects. The EntityDataSource interior decorator enables you to configure an EntityDataSource control easy at design clip.

Similar to LinqDataSource, you can utilize the Configure Data Source ace of the EntityDataSource control to initialise the informations beginning. Figure 5.4 shows the ace.

Initially, the ace enables you to choose a named connexion from the Web.Config file or add a connexion twine to link to the database. The 2nd page of the ace will hold content depending on whether a Select statement configured by the options on the ace is used or some other bid text is used.

5.5.3 ListView

The ListView control is used to adhere and expose informations points from a information beginning. The ListView provides characteristics that support folio, screening, and grouping of points. Using the ListView control, you can execute edit, insert, and delete operations on informations without the demand for any codification.

You can adhere the ListView control to informations by utilizing the DataSourceID belongings. This enables you to adhere the ListView control to a information beginning control, such as the SqlDataSource control. You can besides adhere the ListView control to informations by utilizing the DataSource belongings. This enables you to adhere to assorted objects, which includes ADO.NET datasets and informations readers and in-memory constructions such as aggregations. This attack requires that you write codifications for any extra functionality such as sorting, paging, and updating.

Items that are displayed by a ListView control are defined by templets, likewise to the DataList and Repeater controls. The ListView control lets you expose informations as single points or in groups.

You define the chief layout of a ListView control by making a LayoutTemplate templet. The LayoutTemplate must include a control that acts as a proxy for the information. You define content for single points utilizing the ItemTemplate templet. This templet typically contains controls that are data-bound to data columns or other single informations elements.

Code Snippet 8 shows a ListView control that displays names of classs from the Categories tabular array in Library database.

Code Snippet 8

& lt ; caput runat= '' waiter '' & gt ;

& lt ; title & gt ; ListView Demo & lt ; /title & gt ;

& lt ; manner type= '' text/css '' & gt ;

.table

{

boundary line: thin # 000000 solid ;

border-collapse: prostration ;

boundary line: 1px solid # 000000 ;

}

table td

{

boundary line: 1px solid # FF0000 ;

}

& lt ; /style & gt ;

& lt ; /head & gt ;

& lt ; organic structure & gt ;

& lt ; signifier id= '' form1 '' runat= '' waiter '' & gt ;

& lt ; div & gt ;

& lt ; /div & gt ;

& lt ; br / & gt ;

& lt ; br / & gt ;

& lt ; asp: ListView runat= '' waiter '' ID= '' ListView1 '' DataSourceID= '' SqlDataSource1 '' & gt ;

& lt ; LayoutTemplate & gt ;

& lt ; table runat= '' waiter '' id= '' table1 '' class= '' tabular array '' & gt ;

& lt ; tr runat= '' waiter '' id= '' itemPlaceholder '' & gt ;

& lt ; /tr & gt ;

& lt ; /table & gt ;

& lt ; /LayoutTemplate & gt ;

& lt ; ItemTemplate & gt ;

& lt ; tr id= '' Tr1 '' runat= '' waiter '' & gt ;

& lt ; td id= '' Td1 '' runat= '' waiter '' & gt ;

& lt ; % -- Data-bound content. -- % & gt ;

& lt ; asp: Label ID= '' NameLabel '' runat= '' waiter '' Text= ' & lt ; % # Eval ( `` Category '' ) % & gt ; ' / & gt ;

& lt ; /td & gt ;

& lt ; /tr & gt ;

& lt ; /ItemTemplate & gt ;

& lt ; /asp: ListView & gt ;

& lt ; asp: SqlDataSource ID= '' SqlDataSource1 '' runat= '' waiter '' ConnectionString= '' & lt ; % $ ConnectionStrings: LibraryConnectionString % & gt ; ''

SelectCommand= '' SELECT [ CategoryID ] , [ Category ] FROM [ BookCategories ] '' & gt ; & lt ; /asp: SqlDataSource & gt ;

The end product of this markup is seen in figure 5.6.

5.6 Globalization

• .NET Framework 4
• .NET Framework 3.0
• Ocular Studio 2005
• Ocular Studio.NET 2003

ASP.NET allows you to develop Web applications that can be accessed by 1000000s of users across the Earth. This means that the Web applications should be created taking into consideration the demands of users from assorted parts of the universe. Therefore, you need to internationalise your application to do it accessible to users belonging to different states, parts, civilizations, linguistic communications, and so on. Globalizationinvolves the procedure of developing Web applications that can be used by users from different parts of the universe. These Web applications will be independent of the linguistic communication and civilization.

In short, globalising an application involves doing your application readable to a broad scope of users irrespective the cultural and regional differences.

See a scenario of a medical research company in New York. The company has created a Web application that displays the consequences of different researches carried out by the company. The Web application is created sing a broad scope of users of different linguistic communications and civilizations. This means that the Web site is civilization and linguistic communication specific. Therefore, for a user from United States, the Web site content appears in English and for the user from France, the Web site content appears in French, and so on. But, the company wants to follow a standard format while stand foring the medical marks and symbols. This means that irrespective of the user 's location, the marks and symbols should look same. To implement this, developers can globalise the Web application.

Using ASP.NET, you can make Web applications that can automatically set civilization, and arrange day of the months and currency harmonizing to user demands.

ASP.NET supports globalisation by supplying the System.Globalization namespace. The System.Globalization namespace provides a set of categories to construct applications that can be supported across the Earth. These categories allow you to cover with assorted globalisation issues such as civilization, part, calendar support, and date-time data format. Table 5.1 lists the normally used categories of the System.Globalizationnamespace.

Table 5.1: Normally Used Classs of System.Globalization

For illustration, to expose the currency symbol of the current civilization in your Web application, the codification shown in Code Snippet 9 will be used.

Code Snippet 9

CultureInfo curie = System.Threading.CurrentThread.CurrentCulture ;

NumberFormatInfo nfi = ci.NumberFormat ;

Response.Write ( `` Currency Symbol: `` + nfi.CurrencySymbol + `` & lt ; BR & gt ; '' ) ;

If the current civilization is US, the currency symbol displayed as a consequence of Code Snippet 9 will be $ .

You can put the civilization or an ASP.NET Web page declaratively utilizing one of two attacks: