Executing a "string" block of code

[C# Programming]

Im not sure if this is bad programming or anything of the kind. But I need to be able to save a property of an object without know what the name of the property will be before hand.

I have an object: objUser, object user might have properties name, surname and age.

So I want to be able to say:

objUser.["Name"] = "Philip";

or

string sProperty = "Name";

objUser.[sProperty] = "Philip;

How do I invoke such a string as a property? (if explained correctly)...

Any help would be appreciated.