关于DBGrid的分类颜色显示

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Grids, DBGrids, DB, DBTables;

type
  TForm1 = class(TForm)
    DataSource1: TDataSource;
    Query1: TQuery;
    DBGrid1: TDBGrid;
    PRocedure DBGrid1DrawDataCell(Sender: TObject; const Rect: TRect;
      Field: TField; State: TGridDrawState);
    procedure Query1AfterOpen(DataSet: TDataSet);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  clf:array of Tcolor;
implementation
{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  Query1.Active := False;
  Query1.DatabaseName := 'DBDEMOS';
  Query1.SQL.Add('select * from orders');
  DataSource1.DataSet := Query1;
  Dbgrid1.DataSource := DataSource1;
  Dbgrid1.Align := alClient;
  Query1.Active := True;
end;

procedure TForm1.Query1AfterOpen(DataSet: TDataSet);
var
  i,aa:integer;
  c:Tcolor;
begin
  query1.DisableControls;
  setlength(clf,query1.RecordCount);
  query1.First;
  i := Low(clf);
  clf[i] := clRed;
  c := clRed;
  aa:=1;
  while not query1.Eof do
  begin
    if (query1.RecNo - aa)>9 then
    begin
      aa := aa + 10;
      if c = clRed then c:= clGreen
      else c := clRed;
    end;
    clf[i] := c;
    Inc(i);
    query1.Next;
  end;
  query1.First;
  query1.EnableControls;
end;

procedure TForm1.DBGrid1DrawDataCell(Sender: TObject; const Rect: TRect;
  Field: TField; State: TGridDrawState);
begin
    DBGrid1.Canvas.Brush.Color := clf[Dbgrid1.DataSource.DataSet.RecNo-1+Low(clf)];
    DBGrid1.DefaultDrawDataCell(Rect, Field, State);
end;

end.