How do you define a single blendable design time instance? - data-binding

Question

The default Windows 8 project template has a CollectionViewSource in the template.
<CollectionViewSource
x:Name="itemsViewSource"
Source="{Binding Model.Invitations}"
d:Source="{Binding Invitations, Source={d:DesignInstance Type=vm:DesignerFilteredInvitations, IsDesignTimeCreatable=True}}" />
Obviously not all pages have a collection as their model, you can define a DataContext like this:
<vm:MySingleItemViewModel x:Key="Model" />
How do you define the design instance for this kind of model?

Answer 1

Well, design time data is best accomplished like this: http://blog.jerrynixon.com/2012/08/most-people-are-doing-mvvm-all-wrong.html
I realize your question is asking about using d:DesignInstance which also works with this type of technique - just not demonstrated in that article.
All it requires is a good constructor.

Answer 2

Okay, using this works fine:
<Page
d:DataContext="{d:DesignInstance Type=Models:ViewModel, IsDesignTimeCreatable=True}"
And using this works fine:
<d:Page.DataContext>
<Models:ViewModel/>
</d:Page.DataContext>
I must tell you the latter is an easier approach, too. It is also what Visual Studio will generate when you setup a data source in the designer. It also gives you fully-typed bindings. But either is acceptable.
Another note. I can see no good reason to set an object directly to the source of a CollectionViewSource. Normally you would be binding the CVS's Source property to a property inside your ViewModel. But, given your question: Here's how:
<CollectionViewSource
x:Name="TestCVS" Source="{Binding}"
d:DataContext="{Binding Source={d:DesignInstance Type=Models:ViewModel, IsDesignTimeCreatable=True}}"/>
Binding to the Source in the designer caused me endless trouble. But it irritated me more because I knew I would never do it this way. This is what I wanted to do:
<d:Page.DataContext>
<Models:ViewModel/>
</d:Page.DataContext>
<Page.Resources>
    <CollectionViewSource x:Name="TestCVS" Source="{Binding}" />
</Page.Resources>
You better have a great reason for your approach!
Best of luck!