Cannot like the example grouping

Hello all... 

plz help me i dont know whats wrong with my code ... i tried to follow the example given but my grid can not show like the example 

this the code i write : 

            Using conn As New OleDbConnection(str)
                conn.Open()

                'Fill GridDetail
                daDetail = New OleDbDataAdapter("Select TrProjectDtl.*, MstDetail.NamaDetail, MstBagian.NamaBagian " &
                                                "FROM (TrProjectDtl INNER JOIN MstBagian ON TrProjectDtl.KodeBagian = MstBagian.KodeBagian) INNER JOIN MstDetail ON TrProjectDtl.KodeDetail = MstDetail.KodeDetail " &
                                                "WHERE KodeProject='" & GridHeader.Rows(i).Cells(0).Value.ToString() & "' ORDER BY TrProjectDtl.KodeBagian, TrProjectDtl.KodeDetail", conn)

                dsDetail = New DataSet
                dsDetail.Clear()
                daDetail.Fill(dsDetail, "TrDetail")
                daDetail.Dispose()

                Me.GridDetail.TableElement.BeginUpdate()

                GridDetail.DataSource = (dsDetail.Tables("TrDetail"))

                GridDetail.MasterTemplate.AutoExpandGroups = True
                GridDetail.MasterTemplate.EnableFiltering = True
                GridDetail.ShowGroupPanel = True
                GridDetail.EnableHotTracking = True


                Me.GridDetail.TableElement.EndUpdate(False)

                'GridDetail.TableElement.CellSpacing = -1
                'GridDetail.TableElement.TableHeaderHeight = 35
                'GridDetail.TableElement.GroupHeaderHeight = 30
                'GridDetail.TableElement.RowHeight = 25

                'Me.GridDetail.GroupDescriptors.Clear()
                Me.GridDetail.GroupDescriptors.Add(New GridGroupByExpression("KodeBagian as KodeBagian format ""{0}: {1}"" Group By KodeBagian"))

                'GridHasil.BestFitColumns()

                conn.Close()