Home > Articles > Web Services > XML

Like this article? We recommend

A Final Example

We have the XML defined, and you're now a bit more familiar with the System.Xml namespaces. Copy and paste the code below into a file under <webroot>/bin/test.cs. Create the bin directory, if it does not already exist, because .NET searches for namespaces by default in <webroot>/bin. Listing 4 provides the code that will be used in the custom namespace.

Listing 4: Namespace for Supporting Classes

namespace test
{
   using System;
   using System.Collections;
   using System.Xml;
   using System.Xml.XPath;

   public class Contact
   {
     public Contact()
     {
        szFirstName = String.Empty;
        szLastName  = String.Empty;
        szMiddleName = String.Empty;
     }
     
     public Contact(XPathNavigator oNav, String szId)
     {
        // Grab the contact info and initialize the data [ccc]
members with it. 
        XPathNodeIterator oIterator = oNav.Select[ccc]
("personal_information/contacts/entry[@id='" + szId + "']");
        oIterator.MoveNext();


        XPathNodeIterator oName = oIterator.Current.Select[ccc]
("./name");
        oName.MoveNext();

        szFirstName = GetAttributeText(oName.Current, "first");
        szMiddleName = GetAttributeText(oName.Current, "middle");
        szLastName  = GetAttributeText(oName.Current, "last");
        szInitials  = String.Empty;
        szKeywords  = String.Empty;

        if (GetAttributeText(oName.Current, "gender") == "f")
        {
          szGender = "Female";
        } else {
          szGender = "Male";
        }


        //TODO: Addresses
        oAddresses = new Hashtable();

        Address oHome = new Address(oIterator.Current, "home");
        Address oWork = new Address(oIterator.Current, "work");
        oAddresses.Add("home", oHome);
        oAddresses.Add("work", oWork);

        //TODO: Phone Number
        oPhones = new Hashtable();

        PhoneNumber oPHome = new PhoneNumber(oIterator.[ccc]
Current, "home");
        PhoneNumber oPWork = new PhoneNumber(oIterator.[ccc]
Current, "work");

        oPhones.Add("home", oPHome);
        oPhones.Add("work", oPWork);

     }
     
     public PhoneNumber GetPhoneNumber(String szType)
     {
        return (PhoneNumber) oPhones[szType];
     }

     public Address GetAddress(String szType)
     {
        return (Address) oAddresses[szType];
     }

     private String GetAttributeText(XPathNavigator nav, [ccc]
String szName)
     {
        String szRetval = String.Empty;

        nav.MoveToAttribute(szName, "");
        szRetval = nav.Value;
        nav.MoveToParent();

        return szRetval;
     }

     public String szFirstName;
     public String szMiddleName;
     public String szLastName;
     public String szGender;
     public String szKeywords;
     public String szInitials;

     private Hashtable oAddresses;
     private Hashtable oPhones;
   }

   
   public class Address
   {
     public Address(XPathNavigator oNav, String szType)
     {
        try
        {
          szState = String.Empty;
          szCity = String.Empty;
          szZip  = String.Empty;

          XPathExpression oExpr;
          String szExpr = String.Empty;

          szExpr = "./address[@type='" + szType + "']/line";
          oExpr = oNav.Compile(szExpr);
          
          // Create comparison class for the ISBN number
          ContactCompare oAddressCompare = new [ccc]
ContactCompare();

          // Add a comparer to do a string compare on the [ccc]
ISBN number
          oExpr.AddSort("@seq", (IComparer)oAddressCompare);

          XPathNodeIterator oIterator = oNav.Select(oExpr);
          int x = 0;

          aLines = new String[oIterator.Count];

          while (oIterator.MoveNext())
          {
             aLines[x] = oIterator.Current.Value;
             x++;
          }

          szExpr = "./address[@type='" + szType + "']/city";
          
          oIterator = oNav.Select(szExpr);
          oIterator.MoveNext();
          szCity = oIterator.Current.Value;
          
          szExpr  = "./address[@type='" + szType + "'][ccc]
/state";
          oIterator = oNav.Select(szExpr);
          oIterator.MoveNext();

          szState = oIterator.Current.Value;

          szExpr  = "./address[@type='" + szType + "'][ccc]
/zipcode";
          oIterator = oNav.Select(szExpr);
          oIterator.MoveNext();
        
          szZip = oIterator.Current.Value;
          oIterator.Current.MoveToParent();
        }
        catch (ArgumentException ex)
        {
          String blah = ex.Message;
          szState = String.Empty;
          szCity = String.Empty;
          szZip  = String.Empty;

        }
     }

     public String[] aLines;
     public String szState;
     public String szCity;
     public String szZip;
   }
   
   // does a string compare. used with XPathExpression
   class ContactCompare : IComparer
   {
     public int Compare(Object First, Object Second)
     {
        String s1 = (String) First;
        String s2 = (String) Second;

        return s1.ToString().CompareTo(s2.ToString());
     }

   }
   
   // contains a phone number
   public class PhoneNumber
   {
     public PhoneNumber(XPathNavigator oNav, String szType)	
     {

        String szExpr = String.Empty;
        szExpr = "./phone[@type='" + szType + "']";

        XPathNodeIterator oIterator = oNav.Select(szExpr);

        oIterator.MoveNext();
        
        szACode = GetAttributeText(oIterator.Current, [ccc]
"acode"); 
        szNumber = GetAttributeText(oIterator.Current, [ccc]
"number");
     }

     private String GetAttributeText(XPathNavigator nav, [ccc]
String szName)
     {
        String szRetval = String.Empty;

        nav.MoveToAttribute(szName, "");
        szRetval = nav.Value;
        nav.MoveToParent();

        return szRetval;
     }
     
     public String szACode;
     public String szNumber;
   }

   // Only manages one contacts xml file at a time. 
   public class ContactManager
   {
     public ContactManager(String szFilePath)
     {
        // Initialize the XPath classes.
        oDoc = new XmlDocument();
        oDoc.Load(szFilePath);
        oNav = oDoc.CreateNavigator();
        oNav.MoveToRoot();

        // Get a count of all entries.
        XPathNodeIterator oIterator = oNav.Select[ccc]
("personal_information/contacts/entry");
        iContactCtr = oIterator.Count;

     }

     public Contact GetContact(String szId)
     {
        Contact pTemp = new Contact(oNav, szId);
        return pTemp;
     }

     public Contact GetContact(int Id)
     {
        Contact pTemp = new Contact(oNav, Convert.ToString(Id));
        return pTemp;
     }

     public int Count()
     {
        return iContactCtr;
     }

     private XPathNavigator oNav;
     private XmlDocument  oDoc;
     private int         iContactCtr;
   }

}

Compile the C# file on the command line from the bin directory, which should be located off your working Web root. Run this command to build the code into a namespace:

csc /t:library /r:System.dll /r:System.Data.dll /r:System.Web.dll [ccc]
/r:System.Xml.dll test_lib.cs

If you're an experienced .NET developer, most of this code should be familiar. The ContactManager class is used to accomplish any management tasks, such as getting contacts and counting contacts. The contact class provides an interface into the data. A problem with the current version is that all the variables for storing contact information are declared public. On the plus side, you have the capability to do sorts with the XPathExpression class itself. This class is used minimally in the Address class, but it demonstrates functionality that current XPath implementations do not contain. First, the comparison class is defined:

   class ContactCompare : IComparer
   {
     public int Compare(Object First, Object Second)
     {
        String s1 = (String) First;
        String s2 = (String) Second;

        return s1.ToString().CompareTo(s2.ToString());
     }

   }

Then the user-defined comparison class is used with an XPath selection of sorts. In our case, this is the Address class to sort the line nodes by the seq attribute:

...
   XPathExpression oExpr;
   String szExpr = String.Empty;

   szExpr = "./address[@type='" + szType + "']/line";
   oExpr = oNav.Compile(szExpr);
   
   // Create comparison class for the ISBN number
   ContactCompare oAddressCompare = new ContactCompare();

   // Add a comparer to do a string compare on the ISBN number
   oExpr.AddSort("@seq", (IComparer)oAddressCompare);

   XPathNodeIterator oIterator = oNav.Select(oExpr);
...

The sorting capabilities in XPathExpression are welcome addition to the System.Xml.XPath namespace. A developer actually has another option to do, rather than fumbling through XSL to complete the job.

The design is simple and meets our needs of providing an interface into the data. Because both classes are contained in a namespace, building a Web Service on top of any functionality would be trivial with .NET. If there aren't any compiler errors, let's proceed to actually build out a Web page to use the namespace.

All the real data work is done in the namespace, which makes the Web page itself very simple. Of course, that is the purpose of abstracting the work away from the UI (see Listing 5).

Listing 5: Using the Supporting Test Namespace to Build an HTML Page for a User

<%@Page language="C#" %>
<%@Import Namespace="test" %>

<html>
<script runat="server">
   XPathDocument myXPathDocument;
   ContactManager oMgr;

   void Page_Load(Object sender, EventArgs e)
   {
     oMgr = new ContactManager(Server.MapPath("contacts.xml"));

     int iCtr = oMgr.Count();
     
     for(int x = 0; x < iCtr; x++)
     {
        Contact pTemp = oMgr.GetContact(x);
        Response.Write(pTemp.szFirstName + " " + [ccc]
pTemp.szMiddleName + " " + pTemp.szLastName + "<br>");

        Address oHomeAddress = pTemp.GetAddress("home");
        DisplayAddress(oHomeAddress);
        Response.Write("<br>");

        PhoneNumber oWorkPhone = pTemp.GetPhoneNumber("work");
        PhoneNumber oHomePhone = pTemp.GetPhoneNumber("home");

        Response.Write("Work =");
        DisplayPhone(oWorkPhone);
        Response.Write("<br>");

        Response.Write("Home =");
        DisplayPhone(oHomePhone);
        Response.Write("<br><br>");
     }
   }

   private void DisplayAddress(Address oData)
   {
     for (int i = 0; i < oData.aLines.Length; i++)
     {
        Response.Write(oData.aLines[i] + "<br>");
     }
   
     Response.Write(oData.szCity + "," + oData.szState + [ccc]
"&nbsp;&nbsp;&nbsp;&nbsp;" + oData.szZip);
   }

   private void DisplayPhone(PhoneNumber oData)
   {
     Response.Write("(" + oData.szACode + ")" + oData.szNumber);
   }


   private void DisplayName(XPathNavigator nav)
   {
     String szExpr = String.Empty;
    szExpr = "name";

    XPathNodeIterator oIterator = nav.SelectChildren(szExpr, "");
     oIterator.MoveNext();

     Response.Write(GetAttributeText(oIterator.Current, "first"));
     Response.Write(" " + GetAttributeText(oIterator.Current, [ccc]
"middle"));
     Response.Write(" " + GetAttributeText(oIterator.Current, [ccc]
"last") + "<br>");
   }

</script>
<body>
</body>
</html>

This simple Web page to use the classes in the test namespace is fairly self-explanatory. First, the XML data file is initialized with the proper file. From that point, the count of entry nodes is obtained and the loop just goes through them one by one, displaying the relevant information. This is a nice exercise in accessing custom namespaces, but it's nothing revolutionary. The namespace created earlier is the true workhorse of this example. The XmlDocument was used mostly for its capability to edit as well as select data. The XPathDocument could've been used, but it allows only read-only access. We still can use XPath itself and even can create a XPathNavigator class for use with XSL as well. Because .NET's XML classes are integrated at key levels, it becomes very easy to switch this code from XmlDocument to XPathDocument if we feel the need for speed vs. the extra functionality of XmlDocument. Really, what has been done is that we've used classes that suit the needs of the application—and that is truly what you need to do when building an application in a new platform.

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.

Overview


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.

Surveys

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.

Newsletters

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.

Security


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

Children


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

Marketing


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.

Choice/Opt-out


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.

Links


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