비슷한 코드가 있어서 그냥 남깁니다.
(작자미상요)

<!--CodeS-->
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  Grids, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    StringGrid1: TStringGrid;
    Button3: TButton;
    Button4: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);


  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
type
  TMyGrid = class( TStringGrid ); // Dummy Class
implementation

{$R *.DFM}

procedure InsertRowToStringGrid( Value : TStringGrid; Row : Integer );
var
Soo : TGridRect;
begin
Value.RowCount := Succ( Value.RowCount );
TMyGrid( Value ).MoveRow( Pred( Value.RowCount ), Row );
Soo.Left := 1;
Soo.Top  := Row;
Soo.Right := 1;
Soo.Bottom := Row;
Value.Selection := Soo;
end;

procedure InsertColToStringGrid( Value : TStringGrid; Col : Integer );
var
Soo : TGridRect;
begin
Value.ColCount := Succ( Value.ColCount );
TMyGrid( Value ).MoveColumn( Pred( Value.ColCount ), Col );
Soo.Left := 1;
Soo.Top  := Col;
Soo.Right := 1;
Soo.Bottom := Col;
Value.Selection := Soo;
end;



procedure TForm1.Button1Click(Sender: TObject);
begin
  InsertRowToStringGrid( StringGrid1, 2 );

end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  TMyGrid(stringgrid1 ).deleterow(stringgrid1.Row);
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  InsertColToStringGrid( StringGrid1, 4 );
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  TMyGrid(stringgrid1 ).DeleteColumn(stringgrid1.Col);
end;

end.

<!--CodeE-->

답변 감사합니다. ^^
코드 확인하고, InsertRowToStringGrid 프로시져를 조금 변환해서 잘처리했습니다.
좋은 하루 보내시기 바랍니다. 수고하세요.