Note for future readers: These series discuss WPF and Silverlight versions that are current stable versions at the time of this writing – WPF 3.5 and Silverlight 3.

These are ongoing series of posts on the subject of WPF/Silverlight compatibility. New posts will be added to the Table of Contents post as they are written so bookmark that post or just subscribe to my RSS feed.

In this part I’m going to outline my findings about the differences in one of the fundamental visual aspects of WPF/Silverlight user interface visual appearance – Brush and related issues.

No Brushes in Silverlight

That title sounds scary. It’s not that bad as it may look at the first glance though. I’m talking about Brushes class here (not Brush). Brushes class contains a set of predefined solid color brushes which are very handy shortcuts for specifying solid most common brushes in your code.

In pure WPF you are most probably accustomed to using something like this:

   1: border.Background = Brushes.White;

Well, I have bad news for you. You should forget about this, if you are going to write code that works in both WPF and Silverlight. Fortunately both WPF and Silverlight have Colors class which is almost the same as Brushes except rather than predefined brushes it contains predefined colors. So the above code could be universally rewritten this way:

   1: border.Background = new SolidColorBrush(Colors.White);

A little longer but still better than forking your code for such a small issue.

There’s no difference in setting named brushes in XAML though:

   1: <Border Name="border" Background="White">

   2: </Border>

This works in both.

No Clone() in Silverlight

Well, this is not directly related to brushes, but it’s were I got hit by the absence of object cloning in Silverlight. I’ve cloned my stroke brush in WPF, made it semi-transparent and used that brush as my fill brush. This worked with any type of brush with minimal effort on my side. Unfortunately that happened to be quite a difficult issue in Silverlight. Fortunately Justin Angel has posted a universal Clone() method to Silverlight forums. So, the day is saved once again.

Stroke vs. Pen

WPF has Pen class, Silverlight doesn’t. Pen is a nice class encapsulating all the aspects of a stroke in one reusable object. It’s used in WPF in GeometryDrawing (which is not in Silverlight, too, but I’ll leave it for another installment) and other places. Annoying thing is that it’s dropped in most places (like all the shapes) in favor of separate StrokeXxx properties. I even wrote an extension method and an attached property for the Shape derived classes to use Pen. I’ll share it in a separate post since it’s irrelevant in Silverlight anyway.

In Silverlight you don’t have Pen. Most likely it’s for a simple reason – you don’t have any of the classes that use it anyway. So, if you use Pen somewhere in your WPF code you can be sure that you’ll have to rewrite that code in some greater scope than just changing Pen to StrokeXxx.

No DashStyle in Silverlight

Since there’s no Pen, it’s only logical that there’s no DashStyle, too. You just use StrokeDashArray, StrokeDashCap and StrokeDashOffset instead.