re: Am I right?
Yes you are, indeed. But I found it later, at the time of post I've got an error that some enumerator not implemented.... I did something wrong.....anyway what about question #2 it still open :
b. If I need to find particular row in the grid, by using known value of key field or other field
is any other way then scanning through every row.
e.g. in the same setting :  ContainerGrid g = (ContainerGrid)sender;
how I would search for particular raw with some value without scanning.
I did not see any Find or something method.
Thanks

1. RowUpdating

2.

  <ig:WebScriptManager ID="igwsm" runat="server">
        </ig:WebScriptManager>
        <ig:WebHierarchicalDataGrid ID="whdg" runat="server"
            AutoGenerateColumns="False" DataKeyFields="idMaster" Height="373px"
            Key="idMaster"
            Width="1040px" onrowislandspopulating="whdg_RowIslandsPopulating"
            oncalculatecustomsummary="whdg_CalculateCustomSummary"
            onrowupdating="whdg_RowUpdating">
            <Columns>
                <ig:BoundDataField DataFieldName="idMaster" DataType="System.Int32"
                    Key="idMaster">
                    <Header Text="idMaster" />
                </ig:BoundDataField>
                <ig:BoundDataField DataFieldName="Account" DataType="System.String"
                    Key="Account">
                    <Header Text="Account" />
                </ig:BoundDataField>
                <ig:BoundDataField DataFieldName="Description" Key="Description">
                    <Header Text="Description" />
                </ig:BoundDataField>
                <ig:BoundDataField DataFieldName="Amount" DataType="System.Int64" Key="Amount">
                    <Header Text="Amount" />
                </ig:BoundDataField>
            </Columns>
            <Behaviors>
                <ig:EditingCore EnableInheritance="true" AutoCRUD="False">
                    <Behaviors>
                        <ig:CellEditing EnableInheritance="true">
                            <EditModeActions MouseClick="Single" />
                        </ig:CellEditing>
                    </Behaviors>
                </ig:EditingCore>
                <ig:SummaryRow AnimationEnabled="True" EmptyFooterText="-No- "
                  FormatString="Overall Balance :  ${1}" 
                    ShowSummariesButtons="False"
                    SummariesCssClass="Summary01" EnableInheritance="True" >
               
                    <ColumnSummaries>
                        <ig:ColumnSummaryInfo ColumnKey="Amount">
                            <Summaries>
                                <ig:Summary CustomSummaryName="Cust01" SummaryType="Custom" />
                            </Summaries>
                        </ig:ColumnSummaryInfo>
                    </ColumnSummaries>
                               <%-- <ColumnSettings>
                                    <ig:SummaryRowSetting ColumnKey="Amount"
                                        ShowSummaryButton="False" FormatString="AUX :  {1}"
                                        EnableColumnSummaryOptions="False">
                                        <SummarySettings>
                                            <ig:SummarySetting CustomSummaryName="Alibaba" SummaryType="Sum" />
                                        </SummarySettings>
                                    </ig:SummaryRowSetting>
                                </ColumnSettings>--%>
                            </ig:SummaryRow>
                <ig:Activation>
                </ig:Activation>
            </Behaviors>
        </ig:WebHierarchicalDataGrid>