title: Displaying an alternative text when no image has been assigned yet
body: <p>I have an image control on which the user can drag and drop pictures. When no image has been dropped in there and the control is empty, I'd like to show an alternative text such as "Drop a picture here" to better indicate what is expected from him/her.</p>
  
  <p>I can't figure out how to use triggers with this, this shows nothing at all and I can no longer drop pictures on my image control:</p>
  
  <pre><code>&lt;StackPanel Grid.Column="1" Grid.Row="2" FlowDirection="LeftToRight" Orientation="Horizontal" Margin="0px 4px"&gt;         
      &lt;StackPanel.Resources&gt;
          &lt;DataTemplate x:Key="tmpTemplate"&gt;
  
              &lt;Border BorderThickness="2" BorderBrush="#FF969DFF" CornerRadius="2" VerticalAlignment="Top"&gt;
              &lt;DockPanel&gt;
              &lt;Image Name="imgSelectedViewImage" Source="{Binding Image}" MinWidth="32" MinHeight="32" MaxWidth="48" MaxHeight="48" 
                      HorizontalAlignment="Left" Stretch="None"
                      IsEnabled="{Binding EditMode}" Margin="2px"/&gt;
              &lt;Label Content="Drag here" Name="AltText" Visibility="Collapsed"&gt;&lt;/Label&gt;
              &lt;/DockPanel&gt;
          &lt;/Border&gt;
  
          &lt;DataTemplate.Triggers&gt;
              &lt;DataTrigger Binding="{Binding Path=Image}" Value="{x:Null}"&gt;
              &lt;Setter TargetName="AltText" Property="Visibility" Value="Visible" /&gt;
              &lt;/DataTrigger&gt;
          &lt;/DataTemplate.Triggers&gt;
      &lt;/DataTemplate&gt;
  &lt;/StackPanel.Resources&gt;    
  </code></pre>
  
  <p> </p>