How to change class definition on runtime?

Question

Is there a way for me to change the properties a class has (add/remove properties) on runtime?

Answer 1

You cannot do this unless you are working with an instance of ExpandoObject. The metadata for a CLR type is fixed in the assembly and cannot be changed at execution time. If you really need this kind of dynamic behavior you must use a dynamic type (like EpandoObject) that supports this behavior.

Answer 2

Just to add to Andrew Hare's reply: With C# 4 and .NET 4 you can inherit from DynamicObject and redefine what it means to take various actions on an instance of the type. DynamicObject defines a number of virtual methods that you can override to take control of what it means to e.g. access a property. You could use this to allow properties to be added/removed to the instance, which is pretty much what ExpandoObject does.

For more about ExpandoObject see this question and this blog post.