Having trouble adding TStringLists with chunks

I am trying to separate data coming from a dataset (Q) into chunks of 10 and place them into a TStringList.

I've create a TStringList called LIST, where every time a record is found it adds a value (UID).

I have tried to use an array of TStringLists to keep track, but it's just a bit cumbersome.

The idea would be, for example, given a dataset that delivers 24 records, LIST can have the first 10 values in LIST.strings[0], records 10 to 20 in LIST.Strings[1], and records 21,22 and 23 in LIST.Strings[2].

Any ideas or directions you might think of? I've tried counters also, and it's just not happening. Should I deal with LIST afterwards?

const chunks = 10
List := TStringList.Create;   
Q.Open;
try
  While not Q.EOF Do
  begin
    UID := Q.FieldByname('U_ID');
    List.Add(UID.AsString);
    Q.Next;
  end;
  Q.Close;
finally
  FreeAndNil(Q);
end;
//SO DESIRED OUTPUT SOMETHING LIKE THIS  
//LIST.COUNT =3
//LIST.STRINGS[0] = 1,2,3,4,5,6,7,8,9,10  
//LIST.STRINGS[1] = 11,12,13,14,15,16,17,18,19,20 
//LIST.STRINGS[2] = 21,22,23

I have also tried to use Insert(), like this:

List.QuoteChar := ' ';
if List.Count <= 10 then
begin
  MaxList.Insert(0, List.DelimitedText);
end;
if ((List.Count > 10) and (List.Count <= 20)) then
begin
  MaxList.Insert(1, List.DelimitedText);

But Insert() index doesn't work as I want it.

Solution

If I understand you correctly, your goal is to store the UIDs as comma-separated strings, where each string holds up to 10 UIDs max. If so, try something like this:

const
  chunks = 10;

var
  List: TStringList;
  counter: Integer;
begin
  ...
  counter := 0;
  List := TStringList.Create;   
  try
    Q.Open;
    try
      if not Q.EOF then
      begin
        UID := Q.FieldByName('U_ID');
        repeat
          if (counter mod chunks) = 0 then
            List.Add(UID.AsString)
          else
            List.Strings[List.Count-1] := List.Strings[List.Count-1] + ',' + UID.AsString;
          Inc(counter);
          Q.Next;
        until Q.EOF;
      end;
    finally
      Q.Close;
    end;
    // use List as needed...
  finally
    List.Free;
  end;
  ...
end;

Alternatively, you can use 2 TStringLists instead of a counter, eg:

const
  chunks = 10;

var
  List: TStringList;
  Chunk: TStringList;
begin
  ...
  List := TStringList.Create;   
  try
    Q.Open;
    try
      if not Q.EOF then
      begin
        UID := Q.FieldByName('U_ID');
        Chunk := TStringList.Create;   
        try
          repeat
            if Chunk.Count = chunks then
            begin
              List.Add(Chunk.CommaText);
              Chunk.Clear;
            end;
            Chunk.Add(UID.AsString);
            Q.Next;
          until Q.EOF;
          if Chunk.Count > 0 then
            List.Add(Chunk.CommaText);
        finally
          Chunk.Free;
        end;
      end;
    finally
      Q.Close;
    end;
    // use List as needed...
  finally
    List.Free;
  end;
  ...
end;