WPF x:ArrayExtension

<Window.Resources>
    <x:ArrayExtension x:Key="array" Type="{x:Type sys:Int32}">
        <sys:Int32>20</sys:Int32>
        <sys:Int32>21</sys:Int32>
        <sys:Int32>22</sys:Int32>
    </x:ArrayExtension>
</Window.Resources>
<Grid>
    <ListBox ItemsSource="{StaticResource array}"></ListBox>
</Grid>

Tips

xmlns:sys="clr-namespace:System;assembly=mscorlib"

Sample code

ArrayExtension