Question

I’m trying to develop a simple WP7 app that queries a REST feed which produces a XML file. Depending on the query, the feed can generate many different XML files, but I am having problems with the most basic one.

The XML I am trying to display in a ListBox looks like;

<subsonic-response status="ok" version="1.1.1">
</subsonic-response>

or

<subsonic-response status="ok" version="1.1.1">
<license valid="true" email="[e-mail]" key="ABC123DEF" date="2009-09-03T14:46:43"/>
</subsonic-response>

I’ve tried following several examples from MSDN and other source but I can’t seem to wrap my head around it. The URL that I’m using works because it displays the correct information when entered into a browser, but for some reason isn’t displayed in the ListBox.

Here is the code I am currently using;

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;
using System.Xml.Linq;

namespace RESTTest
{
public partial class MainPage : PhoneApplicationPage
{
    // Constructor
    string requestString =
    "http://WEBSITE/rest/{0}.view?u=USERNAME&p=PASSWORD&v=1.8.0&c=RestTest";
    string UriNoAppId =
    "http://WEBSITE/rest/{0}.view?u=USERNAME&p=PASSWORD&v=1.8.0&c=RestTest";
    public MainPage()
    {
        InitializeComponent();
        List<string> searchTopics = new List<string>() { "ping", "getLicense" };
        comboBox1.DataContext = searchTopics;
        comboBox1.SelectedIndex = 0;
        // Create the WebClient and associate a handler with the OpenReadCompleted event.
        wc = new WebClient();
        wc.OpenReadCompleted += new OpenReadCompletedEventHandler(wc_OpenReadCompleted);
    }
    // Call the topic service at the Bing search site.
    WebClient wc;
    private void CallToWebService()
    {
        // Call the OpenReadAsyc to make a get request, passing the url with the selected search string.
        wc.OpenReadAsync(new Uri(String.Format(requestString, comboBox1.SelectedItem.ToString())));
    }
    void wc_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
    {
        XElement resultXml;
        // You should always check to see if an error occurred. In this case, the application
        // simply returns.
        if (e.Error != null)
        {
            return;
        }
        else
        {
            XNamespace web = "http://subsonic.org/restapi";
            try
            {
                resultXml = XElement.Load(e.Result);
                // Search for the WebResult node and create a SearchResults object for each one.
                var searchResults =
                from result in resultXml.Descendants(web + "WebResult")
                select new SearchResult
                {
                    // Get the Title, Description and Url values.
                    Title = result.Element(web + "version").Value,
                    Url = result.Element(web + "status").Value
                };
                // Set the data context for the listbox to the results.
                listBox1.DataContext = searchResults;
                textBox1.DataContext = searchResults;
            }
            catch (System.Xml.XmlException ex)
            {
                textBlock2.Text = ex.Message;
            }
        }
    }
    private void button1_Click(object sender, RoutedEventArgs e)
    {
        CallToWebService();
    }
    // Update the textblock as the combo box selection changes.
    private void comboBox1_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        uriTextBlock.DataContext = string.Format(UriNoAppId, e.AddedItems[0]);
    }

}
// Simple class to hold the search results.
public class SearchResult
{
    public string Title { get; set; }
    public string Url { get; set; }
}
}

XAML

<phone:PhoneApplicationPage 
x:Class="RESTTest.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="800"
FontFamily="{StaticResource PhoneFontFamilyNormal}"
FontSize="{StaticResource PhoneFontSizeNormal}"
Foreground="{StaticResource PhoneForegroundBrush}"
SupportedOrientations="Portrait" Orientation="Portrait"
shell:SystemTray.IsVisible="False">
<!--LayoutRoot is the root grid where all page content is placed-->
<Grid x:Name="LayoutRoot" Background="Transparent">
    <Grid.Resources>
        <Style x:Key="ComboBoxItemStyle" TargetType="ComboBoxItem" >
            <Setter Property="Foreground" Value="Black"/>
            <Setter Property="Background" Value="LightGray"/>
        </Style>
        <Style x:Key="ComboBoxStyle" TargetType="ComboBox" >
            <Setter Property="Foreground" Value="Black"/>
            <Setter Property="Background" Value="Gray"/>
        </Style>
    </Grid.Resources>
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>
    <!--TitlePanel contains the name of the application and page title-->
    <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
        <TextBlock x:Name="ApplicationTitle" Text="REST CLIENT"
                   Style="{StaticResource PhoneTextNormalStyle}"/>
        <TextBlock x:Name="PageTitle" Text="Subsonic"
                   Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"
                   Height="99" Width="453" />
    </StackPanel>
    <!--ContentPanel - place additional content here-->
    <Grid x:Name="ContentPanel" Margin="12,139,12,0" Grid.RowSpan="2">
        <Button Content="Search!" Height="89" HorizontalAlignment="Left"
                Margin="264,140,0,0" Name="button1"
                VerticalAlignment="Top" Width="189" Click="button1_Click" />
        <ComboBox Height="50" Style="{StaticResource ComboBoxStyle}"
                  HorizontalAlignment="Left" Margin="6,159" Name="comboBox1"
                  ItemContainerStyle="{StaticResource ComboBoxItemStyle}"
                  VerticalAlignment="Top" Width="235" ItemsSource="{Binding}"
                  SelectionChanged="comboBox1_SelectionChanged" />
        <TextBlock Height="36" HorizontalAlignment="Left" Margin="12,120"
                   Name="textBlock2" Text="Search Topic:" VerticalAlignment="Top" width="121" />
        <TextBlock Height="23" HorizontalAlignment="Left" Margin="12,1,0,0"
                   Name="textBlock3"
                   Text="URI:" VerticalAlignment="Top" />
        <TextBlock Height="86" HorizontalAlignment="Left" Margin="6,28"
                   Name="uriTextBlock" TextWrapping="Wrap" Text="{Binding}"
                   VerticalAlignment="Top" Width="447" />
        <TextBlock Height="23" HorizontalAlignment="Left" Margin="12,242,0,0"
                   Name="textBlock5"
                   Text="Results:" VerticalAlignment="Top" />
        <ListBox Height="169" HorizontalAlignment="Left" Margin="6,271,0,0" Name="listBox1"
                 VerticalAlignment="Top" Width="444" ItemsSource="{Binding}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Border BorderBrush="{StaticResource PhoneForegroundBrush}" Width="418"
                            BorderThickness="2" Margin="2">
                        <StackPanel>
                            <TextBlock Text="{Binding Path=Title}" TextWrapping="Wrap" />
                            <TextBlock Text="{Binding Path=Url}" TextWrapping="Wrap"/>
                        </StackPanel>
                    </Border>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
        <TextBox Height="209" HorizontalAlignment="Left" Margin="6,446,0,0" Name="textBox1" Text="" VerticalAlignment="Top" Width="444" IsEnabled="True" IsReadOnly="True" />
    </Grid>
</Grid>
</phone:PhoneApplicationPage>

The code is currently designed so you can choose to display either one of the example XML files, but nothing is displayed in the Listbox at all.

Any advice would be appreciated. Thank you.

Answer 1

See if the following helps:

string fakeXML = "<subsonic-response status='ok' version='1.1.1'>" +
                 "<license valid='true' email='[e-mail]' " +
                 "  key='ABC123DEF' date='2009-09-03T14:46:43'/>" +
                 "</subsonic-response>";
XDocument doc = XDocument.Parse(fakeXML);

var searchResults = from xe in doc.Elements("subsonic-response")
                    select new SearchResult
                    {
                      Title = xe.Attribute("version").Value,
                      Url = xe.Attribute("status").Value
                    };
listBox1.DataContext = searchResults;
textBox1.DataContext = searchResults;