如何在DBGrid的每一行前加一个单选框？

Unit Unit1;

Interface

Uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Grids, DBGrids, DB, ADODB;

Type
  TForm1 = Class(TForm)
    DataSource1: TDataSource;
    ADOTable1: TADOTable;
    DBGrid1: TDBGrid;
    Procedure DBGrid1DrawColumnCell(Sender: TObject; Const Rect: TRect;
      DataCol: Integer; Column: TColumn; State: TGridDrawState);
    Procedure DBGrid1ColEnter(Sender: TObject);
    Procedure DBGrid1ColExit(Sender: TObject);
    Procedure DBGrid1CellClick(Column: TColumn);
    Procedure DBGrid1KeyDown(Sender: TObject; Var Key: Word;
      Shift: TShiftState);
  private
    OriginalOptions: TDBGridOptions;
    Procedure SaveBoolean;
    { Private declarations }
  public
    { Public declarations }
  End;

Var
  Form1: TForm1;

Implementation

{$R *.dfm}

Procedure TForm1.DBGrid1DrawColumnCell(Sender: TObject; Const Rect: TRect;
  DataCol: Integer; Column: TColumn; State: TGridDrawState);
Const // 这个整数值将按照布尔值返回，并送入数组
  CtrlState: Array[Boolean] Of Integer = (DFCS_BUTTONCHECK, DFCS_BUTTONCHECK Or DFCS_CHECKED);
 // CtrlString:=string;
Begin
//确保只有在逻辑字段才能插入组件
  If Column.Field.DataType = ftBoolean Then
  Begin
    DBGrid1.Canvas.FillRect(Rect);
    DrawFrameControl(DBGrid1.Canvas.Handle, Rect, DFC_BUTTON, CtrlState[Column.Field.AsBoolean]); //画框框
   // Column.Field.Text:='google';

  End;
End;

Procedure TForm1.DBGrid1ColEnter(Sender: TObject);
Begin
// 确保该栏是逻辑字段
  If DBGrid1.SelectedField.DataType = ftBoolean Then
  Begin
    OriginalOptions := DBGrid1.Options;
    DBGrid1.Options := DBGrid1.Options - [dgEditing];
  End;
End;

Procedure TForm1.DBGrid1ColExit(Sender: TObject);
Begin
//确保该栏是逻辑字段
  If DBGrid1.SelectedField.DataType = ftBoolean Then
    DBGrid1.Options := OriginalOptions;
End;

Procedure TForm1.DBGrid1CellClick(Column: TColumn);
Begin
//确保该栏是逻辑字段
  If DBGrid1.SelectedField.DataType = ftBoolean Then
    SaveBoolean();
End;

Procedure TForm1.DBGrid1KeyDown(Sender: TObject; Var Key: Word;
  Shift: TShiftState);
Begin
//确保该栏是逻辑字段和空格键在键盘中被敲击
  If (Key = VK_SPACE) And (DBGrid1.SelectedField.DataType = ftBoolean) Then
    SaveBoolean();
End;

Procedure TForm1.SaveBoolean;
Begin
  DBGrid1.SelectedField.Dataset.Edit;
  DBGrid1.SelectedField.AsBoolean := Not DBGrid1.SelectedField.AsBoolean;
  DBGrid1.SelectedField.Dataset.Post;
End;
End.