Sort StringList

function CompareDates(List: TStringList; Index1, Index2: Integer): Integer;
var
  d1, d2: TDateTime;
begin
  d1 := StrToDate(List[Index1]);
  d2 := StrToDate(List[Index2]);
  if d1 < d2 then
    Result := -1
  else if d1 > d2 then Result := 1
  else
    Result := 0;
end;

{ To sort Integer values:}
function CompareInt(List: TStringList; Index1, Index2: Integer): Integer;
var
  d1, d2: Integer;
  r1, r2: Boolean;

  function IsInt(AString : string; var AInteger : Integer): Boolean;
  var
    Code: Integer;
  begin
    Val(AString, AInteger, Code);
    Result := (Code = 0);
  end;

begin
  r1 :=  IsInt(List[Index1], d1);
  r2 :=  IsInt(List[Index2], d2);
  Result := ord(r1 or r2);
  if Result <> 0 then
  begin
    if d1 < d2 then
      Result := -1
    else if d1 > d2 then
      Result := 1
    else
     Result := 0;
  end else
   Result := lstrcmp(PChar(List[Index1]), PChar(List[Index2]));
end;

// Sort Dates
procedure TForm1.Button1Click(Sender: TObject);
var
  sl: TStringList;
begin
  sl := TStringList.Create;
  try
    // listbox1.Sorted := False !
    sl.Assign(listbox1.Items);
    sl.CustomSort(CompareDates);
    listbox1.Items.Assign(sl);
  finally
    sl.Free
  end;
end;

// Sort Integers
procedure TForm1.Button2Click(Sender: TObject);
var
  sl: TStringList;
begin
  sl := TStringList.Create;
  try
    // listbox1.Sorted := False;
    sl.Assign(listbox1.Items);
    sl.CustomSort(CompareInt);
    listbox1.Items.Assign(sl);
  finally
    sl.Free;
  end;
end;