i want hidden two field in my grid ,and i write code like this .

<igtbl:UltraGridBand>
                        <Columns>
                            <igtbl:UltraGridColumn BaseColumnName="SYSID" Hidden="True" IsBound="True" Key="SYSID">
                                <Header Caption="SYSID">
                                </Header>
                            </igtbl:UltraGridColumn>
                            <igtbl:UltraGridColumn BaseColumnName="DCODE" Hidden="True" IsBound="True" Key="DCODE">
                                <Header Caption="DCODE">
                                    <RowLayoutColumnInfo OriginX="1" />
                                </Header>
                                <Footer>
                                    <RowLayoutColumnInfo OriginX="1" />
                                </Footer>
                            </igtbl:UltraGridColumn>
                            <igtbl:UltraGridColumn BaseColumnName="DNAME" IsBound="True" Key="DNAME">
                                <Header Caption="DNAME">
                                    <RowLayoutColumnInfo OriginX="2" />
                                </Header>
                                <Footer>
                                    <RowLayoutColumnInfo OriginX="2" />
                                </Footer>
                            </igtbl:UltraGridColumn>
                        </Columns>
                        <AddNewRow View="NotSet" Visible="NotSet">
                        </AddNewRow>
                    </igtbl:UltraGridBand> 

but after i set BaseTableName and DataKeyField like this to make update and delere working,it don't working of hidden anymore ,just show all field again

this is the code i modifed :

<igtbl:UltraGridBand DataKeyField="DCODE" BaseTableName="doc_yanse">  

can anyone please tell me why?and any solution for that?