Question

I have an application where I need to populate a textbox with a company name and I have filled a custom AutoCompleteStringColection with all the available company names from the database. When a user enters changes the company name by typing and selecting from the list a new company name I need to have the id (Guid), of the selected company so I can do a lookup and get the rest of the company information. Because the company name is not guaranteed to be unique I cannot do a lookup on the name and expect to have the right record. I looked at extending the string class, but all I can find are examples that add methods. I tried that by adding a variable to store the id and methods to get and set the id, but when retrieving the id it is always the last id set. Can a property be added to a class by extending it? I have already changed what I was trying to do to do a lookup on the company name and display a list the user will choose from if multiple matches are returned, but I would still like to know if I can add a property this way in case it comes up again.

Answer 1

No, you cannot extend classes with properties. Additionally, String is sealed so you can’t extend it by inheriting. The only recourse is to composition: encapsulate string in your own class.