How do you specify a different base class in .xaml files (Silverlight)?

Question

How can you specify a common base class in .xaml files for seperate Silverlight Page classes? I have a few common properties that I would like to share across pages, but I don't know how to do this without manually changing the base class in the .g.cs files each time they are generated.

Is this possible? I assume it is possible, since the ChildControl in the Toolkit, for example, derives from a different class. Am I overlooking something obvious?

Answer 1

All Silverlight "pages" are actually deriving from UserControl by default. So, here's what you need to do. Simple example, of course you'd probably want to declare Dependency properties, events, and more.

1. Create your class with the common properties

public class YourUserControlBase : UserControl
{
    public bool SomeProperty {get; set; }
}

2. Create/modify a Page's XAML

Add a XML namespace for the local assembly and namespace that contains your new base class, and remember you keep the x:Class attribute at the top of the file, but modify the UserControl root element to be the local name

Here's my updated file:

<local:YourUserControlBase
xmlns:local="clr-namespace:SilverlightApplication1"
x:Class="SilverlightApplication1.MainPage"
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" 
mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">

Modify the code-behind

(the Page.xaml.cs file, not the auto-generated one) to properly inherit from YourUserControlBase:

public partial class MainPage : YourUserControlBase
{
    public MainPage()
    {
        InitializeComponent();
    }
}

That should be it! Good luck.

Answer 2

Also: when your base class is in an other assembly (project) you can do this:

xmlns:Custom="clr-namespace:SilverlightApplication1;assembly=[Other.Assembly]"