Author: Tomas Rutkauskas

How to sort rows in a TStringGrid

Answer:

1   type
2     TMoveSG = class(TCustomGrid); {reveals protected MoveRow procedure}
3   
4   procedure SortGridByCols(Grid: TStringGrid; ColOrder: array of integer);
5   var
6     i, j: integer;
7     Sorted: boolean;
8   
9     function Sort(Row1, Row2: integer): integer;
10    var
11      C: integer;
12    begin
13      C := 0;
14      result := AnsiCompareStr(Grid.Cols[ColOrder[C]][Row1],
15        Grid.Cols[ColOrder[C]][Row2]);
16      if result = 0 then
17      begin
18        Inc(C);
19        while (C <= High(ColOrder)) and (result = 0) do
20        begin
21          result := AnsiCompareStr(Grid.Cols[ColOrder[C]][Row1],
22            Grid.Cols[ColOrder[C]][Row2]);
23          Inc(C);
24        end;
25      end;
26    end;
27  
28  begin
29    if SizeOf(ColOrder) div SizeOf(i) <> Grid.ColCount then
30      exit;
31    for i := 0 to High(ColOrder) do
32      if (ColOrder[i] < 0) or (ColOrder[i] >= Grid.ColCount) then
33        exit;
34    j := 0;
35    Sorted := false;
36    repeat
37      inc(j);
38      with Grid do
39        for i := 0 to RowCount - 2 do
40          if Sort(i, i + 1) > 0 then
41          begin
42            TMoveSG(Grid).MoveRow(i + 1, i);
43            Sorted := false;
44          end;
45    until
46      Sorted or (j = 1000);
47    Grid.Repaint;
48  end;
49  
50  procedure TForm1.Button1Click(Sender: TObject);
51  var
52    c, r: integer;
53  begin
54    {just fills with random numbers for example}
55    for r := 0 to StringGrid1.RowCount - 1 do
56    begin
57      for c := 0 to StringGrid1.ColCount - 1 do
58      begin
59        StringGrid1.Cols[c][r] := Format('%.3d', [Random(255)]);
60      end;
61    end;
62  end;
63  
64  procedure TForm1.Button2Click(Sender: TObject);
65  begin
66    {example}
67    SortGridByCols(StringGrid1, [1, 0, 2, 3, 4]);
68  end;
69  
70  procedure TForm1.FormCreate(Sender: TObject);
71  begin
72    Randomize;
73  end;