Home > Articles > Programming > Windows Programming

  • Print
  • + Share This
This chapter is from the book

This chapter is from the book

Consuming Web Services

.NET Web Services is a form of distributed computing that enables your application to use the logic of a remote component over the Internet using standard protocols. Web Services is one of the most exciting aspects of using the Compact Framework on a mobile device such as Pocket PC, because it enables you to create rich applications that can access Web Service data from one or many sources without being tethered to a desktop.

For example, consider a Pocket PC device that has a GPS unit attached to it over the serial port (you may someday even be able to use a Pocket PC Phone Edition device to request your current position based on the nearest cellular tower). You could hypothetically use a Web Service to request a map of you current surroundings based on the longitude and latitude that the GPS provides. You could then access another Web Service to get a list of the ATMs or restaurants in your local area. By using Web Services, your applications can focus on tying remote data together into a useful program, rather than concentrate on how to get the data to your device, or replicate functionality that has already been developed elsewhere.

The .NET Compact Framework supports the following functionality regarding Web Services on a Pocket PC device:

  • All Web Services must be based on the HTTP protocol. Other protocols, such as SMTP, are not supported.

  • Data is transmitted using the Simple Object Access Protocol (SOAP) XML format.

  • The Compact Framework supports consuming Web Services by client applications only, and does not natively support hosting them. If you need to support hosting a Web Service using the Compact Framework, you can manually build an HTTP listener (using the TcpListener class) and manually handle incoming SOAP requests.

A great Web site for finding Web Services that are publicly available on the Internet is www.xmethods.com. There you can find Web Services for everything from currency conversion to stock quotes.

In the next section, you will learn what is involved on the client side to consume a Web Service on the Pocket PC.

The Microsoft TerraServer Web Service

The Microsoft TerraServer, located at http://terraserver.microsoft.com, is a massive database (about 3.3 terabytes) of both satellite images and topographic maps for much of the United States. By using TerraServer’s search engine, you can zoom in on aerial images for almost any street in the U.S., as well as obtain data about surrounding landmarks. TerraServer fortunately also provides a Web Service that you can use to perform queries and get maps from the database (which is rather nice, as it would be rather difficult to store all 3.3 terabytes on a Pocket PC).

In this section, we will use the TerraServer Web Services (also called TerraService) as an example of how you can use and consume .NET Web Services on a Pocket PC device using the .NET Compact Framework. More information about the Web Service API that TerraServer provides is available at http://terraserver.homeadvisor.msn.com/webservices.aspx.

The first thing you need to do to consume a Web Service is create a new project. To do this, select the Smart Device Application project type under the Visual C# Project tree. For this example, let’s call the new project TerraServiceTest.

After the project has been created, you need to add a new reference for the Web Service you are planning to use in your class. All you need to do is right-click on References in the Solution Explorer and select Add Web Reference (see Figure 12.1).

12fig01.gifFigure 12.1. Adding a Web reference

The Add Web Reference dialog box will appear (see Figure 12.2). In it, you specify the URL for the WSDL or ASMX file that describes the Web Service. The TerraServer Web Service description is located at http://terraserver.homeadvisor.msn.com/TerraService.asmx.

12fig02.jpgFigure 12.2. Entering the URL for the Web Service

After you have entered the URL, click the Add Reference button. This will cause Visual Studio to generate a proxy class that will be used by your project to access the Web Service. Once this has completed, you will notice that the reference to the Web Service is now in your project (see Figure 12.3).

12fig03.gifFigure 12.3. The Web reference is added to the project.

Now, all you need to do to use the TerraServer Web Service is add the namespace to your current project as follows:

using TerraServiceTest.com.msn.homeadvisor.terraserver;

That’s it! Your C# program can now use the APIs and structures that are part of the Web Service just as if the component were on the device.

Let’s take a look at some sample code that uses TerraService to download a “tile” of satellite image data for the Redmond, Washington, area:

using System;
using System.Data;
using System.IO;
using TerraServiceTest.com.msn.homeadvisor.terraserver;

namespace TerraServiceTest {
   /// <summary>Summary description for Class1. </summary>
   class Class1 {
      /// <summary> The main entry point for the
      /// application. </summary>
      static void Main(string[] args) {
         // Create a new TerraService object
         TerraService ts = new TerraService();

         // Build a place to request tile information on
         Place pl = new Place();
         pl.City = "Redmond";
         pl.State = "WA";
         pl.Country = "USA";
         PlaceFacts pf = ts.GetPlaceFacts(pl);

         // Get the bounding box for the area
         AreaBoundingBox abb = ts.GetAreaFromPt(pf.Center,
            Theme.Photo, Scale.Scale16m, 640, 480);

         // Grab the center tile
         Byte[] imageBytes = ts.GetTile(abb.Center.

         // Create a new file and dump the buffer to it
         FileStream outputFileStream = new FileStream
            ("\\map.jpg", FileMode.CreateNew);
         BinaryWriter outputBinaryWriter = new BinaryWriter

         // Write
         outputBinaryWriter.Write(imageBytes, 0, imageBytes.

         // Clean up

After the class has completed, you can view the downloaded map by launching Pocket Internet Explorer (see Figure 12.4).

12fig04.gifFigure 12.4. Satellite map of the Redmond, WA, area downloaded via TerraServer

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020