Show DB data in nested Datagrid in WPF ?

Hi every 1

Please i'm new with WPF, i have DB with 2 tables (Customers_details,Customers_Activities) and i want my WPF (vb.net) app datagrid to do the following :

--> inner datagrid as row details templatefor the 1st datagrid to show the Customer activities when user clicks the row.
is it possible to make something like this with the same datagrid ??

below is my code, i just cant bind the inner datagtid to the Activities datatable !

<Grid><DataGrid AutoGenerateColumns="False" Name="DataGrid1"><DataGrid.Columns><DataGridTextColumn Header="Customer ID" Width="100" Binding="{Binding Cus_ID}"/><DataGridTextColumn Header="Customer Name" Width="200" Binding="{Binding Cus_Name}"/></DataGrid.Columns><DataGrid.RowDetailsTemplate><DataTemplate><DataGrid  Name="DG1" ItemsSource"{Binding source=dt1}" ><DataGridTextColumn Header="Activity ID" Width="100" Binding="{Binding Act_ID}"/><DataGridTextColumn Header="Description" Width="200" Binding="{Binding Desc}"/></DataGrid></DataTemplate></DataGrid.RowDetailsTemplate></DataGrid></Grid>

  Private Sub Window_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded
        Dim da As New OleDbDataAdapter("select Cus_ID,Cus_Name from Customers_details", con)
        Dim dt As New DataTable
        da.Fill(dt)
        DataGrid1.ItemsSource = dt.DefaultView
    End Sub
    Private Sub DataGrid1_SelectionChanged(ByVal sender As System.Object, ByVal e As System.Windows.Controls.SelectionChangedEventArgs) Handles DataGrid1.SelectionChanged
        Dim drv As System.Data.DataRowView = CType(DataGrid1.SelectedItem, System.Data.DataRowView)
        Dim da1 As New OleDbDataAdapter("select Act_ID,Desc from Customers_Activities where Cus_ID='" & drv.Item(1).ToString & "'", con)
        Dim dt1 As New DataTable
        da1.Fill(dt1)
    End Sub