title: The tag 'DataTrigger' does not exist in XML namespace?
body: <p>I am getting a really annoying error </p>
  
  <p>Error   175 The tag 'DataTrigger' does not exist in XML namespace '<a href="http://schemas.microsoft.com/winfx/2006/xaml/presentation" rel="nofollow noreferrer">http://schemas.microsoft.com/winfx/2006/xaml/presentation</a>'.  </p>
  
  <p>I am using Visual Studio 2010 with Silverlight 5.  As far as I can tell the references are ok but obviously not, can someone tell me what is causing this please</p>
  
  <p>I believe this may resolve the other question I raised earlier but cant test it because of this error</p>
  
  <p><a href="https://stackoverflow.com/questions/12020194/change-datatemplate-to-use-depending-on-condition">Change DataTemplate to use depending on condition</a></p>
  
  <pre><code>xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"             
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  xmlns:iv="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" 
  xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"
  xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"  
  
  mc:Ignorable="d"    
  &gt;
  &lt;UserControl.Resources&gt;
    &lt;DataTemplate x:Key="SelectControl"&gt;
      &lt;ContentControl Content="{Binding}"&gt;
          &lt;ContentControl.Style&gt;
              &lt;Style TargetType="ContentControl"&gt;
                  &lt;Style.Triggers&gt;
                      &lt;DataTrigger Binding="{Binding BlockType}" Value="Locked"&gt;
                          &lt;Setter Property="DataTemplate"
                                  Value="{StaticResource LockedClip}" /&gt;
                      &lt;/DataTrigger&gt;
                      &lt;DataTrigger Binding="{Binding BlockType}" Value="Unlocked"&gt;
                          &lt;Setter Property="DataTemplate"
                                  Value="{StaticResource UnlockedClip}" /&gt;
                      &lt;/DataTrigger&gt;
                      &lt;DataTrigger Binding="{Binding BlockType}" Value="Unlock"&gt;
                          &lt;Setter Property="DataTemplate"
                                  Value="{StaticResource UnlockClip}" /&gt;
                      &lt;/DataTrigger&gt;                      
                  &lt;/Style.Triggers&gt;
              &lt;/Style&gt;
          &lt;/ContentControl.Style&gt;
      &lt;/ContentControl&gt;
  &lt;/DataTemplate&gt;
  
  &lt;DataTemplate x:Key="LockedClip"&gt;
    &lt;my:SingleLockedFlexBlock Height="117"/&gt;            
  &lt;/DataTemplate&gt;    
  
  &lt;DataTemplate x:Key="UnlockedClip"&gt;
    &lt;my:SingleLockedFlexBlock Height="50"/&gt;            
  &lt;/DataTemplate&gt;    
  
   &lt;DataTemplate x:Key="UnlockClip"&gt;
     &lt;my:SingleLockedFlexBlock Height="200"/&gt;            
   &lt;/DataTemplate&gt;    
  </code></pre>
  
  <p>  </p>
  
  <p>Hope someone can shed light on this?</p>
  
  <p>Paul</p>