Collection Control and Attached Property

I have 2 questions:

1) I want to create a collection control that i can use i开发者_运维知识库n xaml like this:

<local:MyCollection x:Key="mc">
   <local:MyCollection.Groups>
      <local:MyCollectionGroup x:Name="CG1"/>
      <local:MyCollectionGroup x:Name="CG2"/>
   </local:MyCollection.Groups>
</local:MyCollection>

<TextBox local:CollectionControl=mc/>

How can i do this?

2) Similiar to the above.

<local:MyCollectionGroup x:Name="CG1"/>
<local:MyCollectionGroup x:Name="CG2"/>

<TextBox local:CollectionControl=CG1,CG2/>

Have you looked into using a CompositeCollection? http://msdn.microsoft.com/en-us/library/system.windows.data.compositecollection.aspx

Typically you'd do something like

<local:MyCollection x:Key="mc">
    <CompositeCollection>
        <local:MyCollectionGroup x:Name="CG1"/>
        <local:MyCollectionGroup x:Name="CG2"/>
    </CompositeCollection>
</local:MyCollection>