title: is it possible to give the underline bar of a picker a color?
body: <p>Is it possible to change the underline of an picker (photo) in Xamarin Forms? I am trying to make a nice validation error.</p>
  
  <p>Are there also other tricks to make a nice design?</p>
  
  <pre><code>&lt;Label HorizontalOptions="Fill" 
         VerticalOptions="Center" 
         HorizontalTextAlignment="End"
         Text="*" 
         TextColor="Red"
         x:Name="lbldocid" 
         Grid.Column="0" 
         Grid.Row="3" 
         IsVisible="false"/&gt;
  &lt;Label Grid.Row="3" 
         Grid.Column="1"
         x:Name="lbldocumentid"  
         Text="Document id: " 
         WidthRequest="100" 
         HorizontalOptions="Fill"
         VerticalOptions="Center" 
         HorizontalTextAlignment="End"/&gt;
  &lt;StackLayout x:Name="sldocid" 
               Padding="1" 
               Margin="20,0,20,0"
               Orientation="Vertical" 
               Grid.Row="3"
               Grid.Column="2"&gt;
      &lt;Picker  x:Name="pickerdocid"
               BackgroundColor="#fafafa"  
               HorizontalOptions="Fill"/&gt;
      &lt;Label x:Name="lbldociderror"
             Margin="5,0,0,0"
             IsVisible="false" 
             TextColor="White" 
             FontSize="12" 
             Text="You need to select documentid."/&gt;
  &lt;/StackLayout&gt;
  </code></pre>
  
  <p>photo:
  <a href="https://i.stack.imgur.com/zTPJI.png" rel="nofollow noreferrer">picker</a></p>