i managed to get a solution for this see below any comments welcome:
CODEBEHIND:
Public Sub Page_Load(Sender As Object, E As EventArgs)
if not IsPostBack then
lblMessage.Text = "Portal Content Displayed"
' make connection show first data set
BindDataList(0)
end if
End Sub
'CAPTURE EVENTS WITH FOLLOWING METHODS
Public Sub DataList_ItemCommand( s as object, e as DataListCommandEventArgs )
dlstTitles.SelectedIndex = e.Item.ItemIndex
Dim intForumID As Integer
intForumID = dlstTitles.DataKeys( e.Item.ItemIndex )
lblMessage.Text = "ID " + intForumID.ToString()
BindDataList(intForumID)
end sub
Private Sub BindDataList( forumID As Integer )
Dim strConn as string = "server=147.149.226.14;uid=isdevelopment;pwd=656404;database=Northwind"
Dim MySQL as string = "Select CategoryID, CategoryName from Categories"
Dim MyConn as New SQLConnection(strConn)
Dim ds as DataSet=New DataSet()
Dim Cmd as New SQLDataAdapter(MySQL,MyConn)
Cmd.Fill(ds,"Categories"
Dim cmd2 As SqlDataAdapter = New SqlDataAdapter("select * from Products WHERE CategoryID = " + forumID.ToString(), MyConn)
cmd2.Fill(ds, "Products"
ds.Relations.Add("myrelation", ds.Tables("Categories"

.Columns("CategoryID"

, ds.Tables("Products"

.Columns("CategoryID"

)
dlstTitles.Datasource=ds.Tables("Categories"

.DefaultView
DataBind()
End Sub
aspx file:
<%@ Page Inherits="masterChild" src="masterChild.aspx.vb" %>
<html>
<body>
<form runat="server">
<asp:label id="lblMessage" runat="server" />
<hr>
<asp

ataList
id="dlstTitles"
OnItemCommand="DataList_ItemCommand"
DataKeyField="CategoryID"
Runat="server">
<ItemTemplate>
<asp:LinkButton Text=<%# Container.DataItem("CategoryName"

%> Runat="Server"/>
<asp

ataList runat="server"
Id="ChildDataList"
GridLines="None"
Bordercolor="black"
cellpadding="3"
cellspacing="0"
Headerstyle-BackColor="#8080C0"
Headerstyle-Font-Name="Arial"
Headerstyle-Font-Size="8"
Font-Name="Arial"
Font-Size="8"
datasource='<%# Container.DataItem.Row.GetChildRows("myrelation"

%>'
RepeatColumns="1">
<ItemTemplate>
<asp:LinkButton Text=<%# Container.DataItem("ProductName"

%> Runat="Server"/>
</ItemTemplate>
</asp

ataList>
</ItemTemplate>
</asp

ataList>
</form>
</body>
</html>