WPF - UserControl default Content attribute

ContentPropertyAttribute

I also found the code for supporting collections as the content property on MSDN. TOM_C is to thank for this.

[ContentProperty("SomeObjects")]
public class SomeContainer
{
    private List<SomeObject> _someObjects;
    public List<SomeObject> SomeObjects
    {
        get
        {
            if (null == _someObjects)
                _someObjects = new List<SomeObject>();
            return _someObjects;
        }
    }
}

XAML:

<SomeContainer>
    <SomeObject/>
    <SomeObject/>
    <SomeObject/>
</SomeContainer>