How to find type of datatype stored in string

I have extracted input and output parameters from wsdl and stored in string. example: string type=parameterType. output: type="int".

Now, I want to get the default value of this type (in this case int).

I have tried this: type.GetType(). Result is the type of the class String, however, I want the value's type.

This is so I can get the default value of the actual value's type, not the default value of string e.g. int ==> 0 and not "int" ==> string ==> null.