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:: Web Services :: XWebNews :: Implementation Guides ::

Build Your Own XML/SOAP Web Service Based News Engine:
Display A List Of News Articles

The procedures in this implementation guide require that you have some knowledge of XML and ASP.NET web development with the Microsoft Visual Basic.NET development tool.

The steps in this "how-to" implementation guide are:

• Add a "Web Reference" to the XWebNews Web Service
• Add a "Web Form" to the web application
• Write code in the "Codebehind" of the web form to retrieve the list of News Articles by consuming the XWebNews Web Service
• Implement a Repeater to display the list of News Articles

To download the source code for this "how-to" implementation guide, as well as for additional hints and tips, please read our Final Notes.

Add a "Web Reference" to the XWebNews Web Service

• In your web project, add a Web Reference to the XWebNews web service. Here are 2 ways you can accomplish this:

  • Browse the Solution Explorer, right click on References and select Add Web Reference... from the drop down menu.
  • From the File Menu, select Project - Add Web Reference....

• The Add Web Reference pop-up window will open. In the URL textbox, enter the following URI:

  http://ws.xwebservices.com/XWebNews/XWebNews.asmx?wsdl

• Hit the Enter key or click the Go button located to the right of the URL textbox.
• Change the Web reference name to XWebNews for easier reference.
• Click the Add Reference button to complete this step.

Add a "Web Form" to the Web Application

• In your web project, add a Web Form. This Web Form will display the list of News Article records in your account. Here are 2 ways you can accomplish this:

  • Browse the Solution Explorer, right click the name of your project, and select Add - Add Web Form....
  • From the File Menu, select Project - Add Web Form....
• Change the Name textbox in the Add New Item pop-up provided to news.aspx.

Write code in the "Codebehind" of the web form to retrieve the list of News Articles by consuming the XWebNews Web Service

Based on the documentation for the XWebNews web service, in order to successfully consume the web service, we will need to authenticate first using SOAP Headers. Here's how:

• Open the "Codebehind" of the news.aspx web form we added to the web project in the previous step.

• Since the web service requires SOAP Headers for authentication purposes, we must first create a new instance of the class representing the SOAP Header and then populate the SOAP Header values:

  ' handle authentication
  Dim objAuth As New XWebNews.AuthHeader
  objAuth.LoginName = "<my_login_name>"
  objAuth.Password = "<my_password>"

  NOTE***: Instead of hard-coding the LoginName and Password values, you may want to dynamically read them from the web.config file (LOGIN_NAME and PASSWORD must be added to the <AppSettings> section of the web.config file):

  objAuth.LoginName = System.Configuration.ConfigurationSettings.AppSettings("LOGIN_NAME")
  objAuth.Password = System.Configuration.ConfigurationSettings.AppSettings("PASSWORD")

• Next, we need to create a new instance of the proxy class and assign the SOAP Header object to the member variable of the proxy class representing the SOAP Header:

  'create the XWebNews web service proxy
  Dim objNews As New XWebNews.XWebNews
  objNews.AuthHeaderValue = objAuth

• We are now ready to call the method on the proxy class that communicates with the Web Service method and returns the list of News Article records we want displayed on the web page.

  'store the result in a variable
  Dim strNewsXML As String = objNews.LoadArticles()

Implement a Repeater to display the list of News Articles

In the Codebehind, we need to declare a Repeater and then bind the XML string we received from the SOAP method, in the form of an XMLNodeList, to the Repeater's DataSource. Here's how:

• Declare the Repeater in the Codebehind:

  Protected rptNews As System.Web.UI.WebControls.Repeater

• Load the XML string from the previous step into an XMLDocument:

  'load an XML DOM with the <News> xml string returned by the web service method
  Dim objDOM As New System.Xml.XmlDocument
  objDOM.LoadXml(strNewsXML)

• Bind the XMLDocument's DocumentElement to the Repeater's DataSource and call the DataBind method:

  rptNews.DataSource = objDOM.DocumentElement
  rptNews.DataBind()

In the HTML Editor, we format the Repeater to our liking to display the list of News Articles. We will display the Title, Introduction, Author and the date the article was posted (Date_Created attribute's value). The title will be hyperlinked (URL element's value) so when clicked, the website visitor would navigate to see the entire News Article. Here are the necessary steps:

• Add the Repeater inside the body of your HTML page:

  <asp:Repeater ID="rptNews" Runat="server">
     <ItemTemplate>
     </ItemTemplate>
  </asp:Repeater>

• Inside the Repeater's ItemTemplate, first we display the Title of the News Article hyperlinked - using the URL of the News Article record. Since the Repeater is looping through XML Nodes (<Article>), we need to bind to the <URL> and <Title> element, respectively, then obtain their value:

  <b>
  <a
  href="<%# Container.DataItem.SelectSingleNode("URL").InnerText %>">
  <%# Container.DataItem.SelectSingleNode("Title").InnerText %>
  </a>
  </b>

• Next, we display the Introduction of the News Article. Again, since the Repeater is looping through XML Nodes (<Article>), we need to bind to the <Introduction> element, then get its value:

  <%# Container.DataItem.SelectSingleNode("Introduction").InnerText %>

• Finally, we display the News Article's author and created date. Since Date_Created is an attribute, we must handle it slightly different than an element:

  <%# Container.DataItem.SelectSingleNode("Author").InnerText %>
  <%# Container.DataItem.Attributes.ItemOf("Date_Created").Value %>

Final Notes

The source code for this "how-to" implementation guide can be downloaded by clicking the link below (zip file, contains the source code for all "how-to" implementation guides for the XWebNews Web Service)

XWebNewsClient.zip

The LoadArticlesPaged SOAP method allows for pagination of the records - this comes in handy when dealing with numerous News Articles.

It's always good practice to implement a Try...Catch... error handling technique to handle some or all possible errors that may occur while the code is executing. We strongly recommend that you implement such a technique.