Ultimately your ExpandoObject needs to implement IComparable<T>
or IComparable
to use the technique in the link you reference (assuming you mean the article mentioned in the accepted answer).
If you're referring to this version of ExpandoObject, it does not implement either interface. So, the straightforward answer is to implement one of those two interfaces.
Fundamentally you need to have some knowledge of how to compare two different instances of ExpandoObject to know which to sort before the other.
If your ExpandoObjects are completely dynamic (as opposed to say having certain common properties that are extended dynamically), how logically do you intend to compare two instances for sorting? If you can provide more detail around your question, I can provide a more specific answer.