Vladimir,

I am assuming you are talking about the Infragistics WebHierarchicalDataSource.

This feature should work fine.  Did you set up a DataBinding on the tree for the datasource.  The following code for me brings the first level in initially and fetches subsequent ones.  What exactly was the problem you experienced?  No data?  All data at the start?

            <ig:WebDataTree ID="WebDataTree1" runat="server" Height="300px" Width="200px"
                DataSourceID="WebHierarchicalDataSource1" InitialDataBindDepth="0">
                <DataBindings>
                    <ig:DataTreeNodeBinding DataMember="AccessDataSource1_DefaultView"
                        TextField="TextValue" ValueField="Code" />
                </DataBindings>
            </ig:WebDataTree>
        <ig:WebHierarchicalDataSource ID="WebHierarchicalDataSource1" runat="server">
            <DataRelations>
                <ig:DataRelation ChildColumns="ParentCode"
                    ChildDataViewID="AccessDataSource1_DefaultView" ParentColumns="Code"
                    ParentDataViewID="AccessDataSource1_DefaultView" />
            </DataRelations>
            <DataViews>
                <ig:Dataview id="AccessDataSource1_DefaultView"
                    datamember="DefaultView" datasourceid="AccessDataSource1">
                </ig:Dataview>
            </DataViews>
        </ig:WebHierarchicalDataSource>
        <asp:AccessDataSource ID="AccessDataSource1" runat="server"
            DataFile="~/App_Data/TreeData.mdb"
            SelectCommand="SELECT [Code], [TextValue], [ParentCode] FROM [Data]">
        </asp:AccessDataSource>

regards,

David Young