Delphi Tstringlist, get strings as a quoted, comma delimited string?

Question

I have a Tstringlist containing a list of keys used in a database table. I'd like a simple way to generate one string containing all the keys, with each separated by a comma and enclosed in single quotes. This is so that it can be used in a SQL 'IN' statement eg WHERE FieldX IN ('One','Two','Three').

I've tried using quotechar but it is ignored when reading the commatext. eg the following code

procedure junk;
var
  SL : Tstringlist;
  s : string;
begin
 SL := Tstringlist.Create;
 SL.Delimiter :=','; //comma delimiter
 SL.QuoteChar := ''''; //single quote around strings
 SL.Add('One');
 SL.Add('Two');
 SL.Add('Three');
 try
   s :=  SL.commatext;
   showmessage(s);
 finally
   SL.Free;
 end; //finally
end; //junk

shows the message One,Two,Three - without any quotes.

I know I can do it the long way round, as in

procedure junk;
var
  SL : Tstringlist;
  s : string;
  i : integer;
begin
 SL := Tstringlist.Create;
 SL.Delimiter :=','; //comma delimiter
 SL.Add('One');
 SL.Add('Two');
 SL.Add('Three');
 try
 s := '';
 for I := 0 to SL.Count - 1 do
    begin
    s := s +  ',' + '''' + SL[i] + '''';
    end;
 delete(s,1,1);
 showmessage(s);
 finally
   SL.Free;
 end;//finally
end;

but is there a simpler way using properties of the Tstringlist itself?

Answer 1

Use sl.DelimitedText instead of sl.CommaText to make it follow your settings. CommaText will temporarily change the Delimiter and QuoteChar to some hardcoded values.