hsr///////////////////////////////////////////////////////////
전체를 팁에도 올려서 많은사람들이 손좀보시게 또는 더 좋은 방법이 있는지 공개하겠습니다.

2가지로 해보았습니다.
1은 입력후 보통 숫자형으로
2는 입력시 바꿔가면서
소숫점사용하도록했구요, 정해놓은 셀엔 숫자만 입력 가능하도록,
엔터기일때 옆의 셀로 이동입니다
....

{$R *.dfm}
function gfGetCommaStr(psNum : string) : string;
var
    sFmt : string;
    i : integer;
begin
    sFmt := '#,##0';
    if psNum <> '' then begin
        if pos('.', psNum) > 0 then begin
            sFmt := sFmt+'.';
            for i := 1 to (length(psNum) - pos('.', psNum) ) do
                sFmt := sFmt+'0';
        end;
        Result := FormatFloat(sFmt, StrToFloat(psNum));
    end else
        Result := '0';
end;


procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
var
    Oldalign : word;
begin
    if (ACol in [1,2])and(ARow>=1) then begin
        Oldalign := settextalign(StringGrid1.Canvas.Handle, TA_RIGHT );
        StringGrid1.Canvas.Font := StringGrid1.Font;
        StringGrid1.Canvas.TextRect(Rect,
                                Rect.Right-5,
                               (Rect.Top+Rect.Bottom-StringGrid1.Font.Size-2) div 2,
                                gfGetCommaStr(StringGrid1.cells[ACol,ARow]));
        settextalign(StringGrid1.Canvas.Handle, Oldalign);
    end;

end;

procedure TForm1.StringGrid12KeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
    //엔터키일때 한칸 옆으로
    if (Key = 13)and(TStringGrid(Sender).Col < TStringGrid(Sender).ColCount-1) then
        TStringGrid(Sender).Col := TStringGrid(Sender).Col + 1;
end;
procedure TForm1.StringGrid12KeyPress(Sender: TObject; var Key: Char);
begin
    //위 해당 셀엔 숫자만 입력 가능케함
    if (TStringGrid(Sender).Col in [1,2])and(TStringGrid(Sender).Row>=1) then
      if not(Key in ['0'..'9','.',#8]) then
         Key := #0;
end;


procedure TForm1.StringGrid2SetEditText(Sender: TObject; ACol,
  ARow: Integer; const Value: String);
var
    SetValue, subStr : string;
begin
    if (ACol in [1,2])and(ARow>=1) then begin
        SetValue := StringReplace(Value, ',', '', [rfReplaceAll]);
        if SetValue = '' then exit;
        subStr := '';
        if Pos('.',SetValue) > 0 then begin
           subStr := copy(SetValue,Pos('.',SetValue),Length(SetValue));
           SetValue := copy(SetValue,1,Pos('.',SetValue)-1);
        end;

        SetValue := gfGetCommaStr(SetValue)+subStr;
        if SetValue <> StringGrid2.cells[ACol,ARow] then begin
           StringGrid2.cells[ACol,ARow] := SetValue;
           StringGrid2.EditorMode := True;
        end;
    end;
end;



procedure TForm1.StringGrid2DrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
var
    Oldalign : word;
begin
    if (ACol in [1,2])and(ARow>=1) then begin
        Oldalign := settextalign(StringGrid2.Canvas.Handle, TA_RIGHT );
        StringGrid2.Canvas.Font := StringGrid2.Font;
        StringGrid2.Canvas.TextRect(Rect,
                                Rect.Right-5,
                               (Rect.Top+Rect.Bottom-StringGrid2.Font.Size-2) div 2,
                                StringGrid2.cells[ACol,ARow]);
        settextalign(StringGrid2.Canvas.Handle, Oldalign);
    end;

end;

end.