Nested curly brackets {{ }} in WPF/XAML

What is the meaning of nested curly brackets in attribute values in WPF/XAML markup? As in the foll开发者_如何学Cowing example:

 <ListBox ItemsSource="{Binding Source={StaticResource pictures}}">

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That binds the ItemsSource of the list box to a StaticResource called pictures. It's simply nesting one markup extension in another.

Read about markup extensions in XAML here: http://msdn.microsoft.com/en-us/library/ms747254.aspx

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Nesting of multiple markup extensions is supported by WPF, and each markup extension will be evaluated deepest first.

 <Setter Property="Background"
Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" />

In this usage, the x:Static statement is evaluated first and returns a string. That string is then used as the argument for DynamicResource.

so here

<ListBox ItemsSource="{Binding Source={StaticResource pictures}}">

it will assign the pictures (may be collection) to the itemsource of the listbox

please have look at this http://msdn.microsoft.com/en-us/library/ms747254.aspx#Nesting