title: Loading xml and binding to ListBox is very slow on Windows phone
body: <p>I read this xml file and bind it to listBox:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;category name="category_alphabet" type="grid" icon="icon_alphabet" tabStyle="alphabetic"    tabStepSize="5"&gt;
  &lt;item&gt;
      &lt;id&gt;dk1-1&lt;/id&gt;
      &lt;label&gt;A&lt;/label&gt;
      &lt;file&gt;a&lt;/file&gt;
  &lt;/item&gt;
  &lt;item&gt;
      &lt;id&gt;dk1-2&lt;/id&gt;
      &lt;label&gt;B&lt;/label&gt;
      &lt;file&gt;b&lt;/file&gt;
  &lt;/item&gt;
  .
  .
  .
  </code></pre>
  
  <p>and it has 29 items</p>
  
  <p>i read that xml file with these codes and i call it after InitializeComponent() in page1.xaml constructor :</p>
  
  <pre><code>var loadedData = XDocument.Load("alphabet.xml").Descendants("item");
  
  var alphabetItems = (from query in loadedData select new CategoryItem
  {
      Id = (string)query.Element("id"),
      File = (string)query.Element("file"),
      Label = (string)query.Element("label")
  }).ToList();
  
  ListBoxAlphabet.ItemsSource = alphabetItems;
  </code></pre>
  
  <p>and this is xaml file :</p>
  
  <pre><code>&lt;ListBox x:Name="ListBoxAlphabet"&gt;
      &lt;ListBox.ItemsPanel&gt;
          &lt;ItemsPanelTemplate&gt;
              &lt;toolkit:WrapPanel /&gt;
          &lt;/ItemsPanelTemplate&gt;
      &lt;/ListBox.ItemsPanel&gt;
      &lt;ListBox.ItemTemplate&gt;
          &lt;DataTemplate&gt;
              &lt;StackPanel&gt;
                  &lt;controls:RoundButton Content="{Binding Label}"
                                        FontSize="30" Margin="1" 
                                        ButtonHeight="80" ButtonWidth="80"
                                        HorizontalAlignment="Center" 
                                        RenderTransformOrigin="0.5,0.5"
                                        Background="#FFD0D2D3" Foreground="White"
                                        PressedBrush="#F9A11D" 
                                        BorderBrush="{Binding Background.Color, RelativeSource={RelativeSource Self}}" 
                                        /&gt;
               &lt;/StackPanel&gt;
           &lt;/DataTemplate&gt;
       &lt;/ListBox.ItemTemplate&gt;
   &lt;/ListBox&gt;
  </code></pre>
  
  <p>the speed of reading xml file is ok but the speed of binding to listbox is very slow ! it takes 7-8 seconds to load and it is not normal . 
  what should i do ?</p>