Vista - Getting ContentPropertyAttribute to work

I've got a custom control that has a ContentProperty set to a public
read-only collection property. However, when I try to build my app, it
tells me:
"Cannot set content property 'MyProp' on element 'MyClass'. 'MyProp' has
incorrect access level or its assembly does not allow access"

My class is defined as such:
[ContentProperty("MyProp")]
public class MyClass {
private ICollection _MyProp;
public ICollection MyProp { get {...} }
}

The documentation for the attribute doesn't mention any specific permissions
required, and I don't really see how a public access modifier would be
wrong. Anyone use this attribute and know where I'm erring?

Problem solved: Replace the interface return value with a class, like
List<>. Not sure why that error comes up, though, since it should be a
valid construct, as the property instantiates the value.

"Keith Patrick" <richard_keith_patrick@nospam.hotmail.com> wrote in message
news:Os4TqnoLHHA.140@TK2MSFTNGP04.phx.gbl...
> I've got a custom control that has a ContentProperty set to a public
> read-only collection property. However, when I try to build my app, it
> tells me:
> "Cannot set content property 'MyProp' on element 'MyClass'. 'MyProp' has
> incorrect access level or its assembly does not allow access"
>
> My class is defined as such:
> [ContentProperty("MyProp")]
> public class MyClass {
> private ICollection _MyProp;
> public ICollection MyProp { get {...} }
> }
>
> The documentation for the attribute doesn't mention any specific
> permissions required, and I don't really see how a public access modifier
> would be wrong. Anyone use this attribute and know where I'm erring?
>