What is the practical use of "dynamic" variable in C# 4.0?

Question

What is their use if when you call the method, it might not exist?

Does that mean that you would be able to dynamically create a method on a dynamic object?

What are the practical use of this?

Answer 1

You won't really be able to dynamically create the method - but you can get an implementation of IDynamicMetaObject (often by extending DynamicObject) to respond as if the method existed.

Uses:

• Programming against COM objects with a weak API (e.g. office)
• Calling into dynamic languages such as Ruby/Python
• Potentially making "explorable" objects - imagine an XPath-like query but via a method/property calls e.g. document.RootElement.Person[5].Name["Attribute"]
• No doubt many more we have yet to think of :)