How can I use the {x:Static ...} extension for Phone7 Silverlight apps?

Question

I'm writing a Phone 7 app and I would like to reference constant values in markup. I believe the way one is supposed to do this is via x:Static.

However, Visual Studio keeps claiming it has no knowledge of x:static. What is the secret sauce here? I have the following:

<phone:PhoneApplicationPage 
  ...
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  ...

  <Image Height="{x:Static App.ImageHeight}" ... />
  ...

And of course:

public partial class App : Application
{
  public const double ImageHeight = 100;
  ...

The error message is "The type 'x:Static' was not found. Verify that...".

Answer 1

x:Static is only available in WPF - neither Silverlight for the browser nor Silverlight for Windows Phone 7 support this markup extension.

The usual workaround is to create a (non-static) class that has properties which simply wrap the static properties you want, and create an instance of that as a Resource and bind against it that way.

Example*:

public class StaticSideEnums
{
    public static Side Bid { get { return Side.Bid; } }
    public static Side Ask { get { return Side.Ask; } }
}

In the resources (app.xaml):

<ResourceDictionary>
    <local:StaticSideEnums x:Key="StaticSideEnums"/>
</ResourceDictionary>

In the xaml where it's used:

<toolkit:ListPicker Name="picker" SelectionChanged="OnSelectionChanged">
    <toolkit:ListPickerItem Content="Buy"  Tag="{Binding Bid, Source={StaticResource StaticSideEnums}}" />
    <toolkit:ListPickerItem Content="Sell" Tag="{Binding Ask, Source={StaticResource StaticSideEnums}}" />
</toolkit:ListPicker>

*This example is taken from an answer in Using localized strings in a ListPicker populated from Enum