Values is an indexed string property used to to read or write the Values in the internal storage in the thread-safe data type. The index value is a String that represent a named element in the thread-safe data type. 

Reading or Writing the Values property causes resource protect to be enabled using the Lock method. Resource protection is disabled using the Unlock method prior to reading or writing the value in the TIdStringList instance. 

Use Add to add a string value to the Values. 

Use AddObject to add a TObject instance with a named element in Values. 

Use ObjectByItem to access the TObject associated with a named element in Values.

TIdThreadSafeStringList.Add 

TIdThreadSafeStringList.AddObject 

TIdThreadSafeStringList.ObjectByItem 

TIdThreadSafeStringList.Lock 

TIdThreadSafeStringList.Unlock