Drop Down menu for String Attributes

Hi Guys, I have an entity 'Candidate' which stores all candidate details. I want to have drop down menu which shows all candidate name(String attribute). The drop down widget only accept attributes of type Enumeration. In my case, name attribute is of String type. So could you please help me to achieve this functionality. Thanks in advance.
1 answers

Enumeration is not really complicate

You can change it and fill it with a right Possibilities (red, blue, green) 

And after that you take it for your Widget