trying to populate a datagrid in a windows form.
using the clsDataSet to return a dataset as below:

The function PopulateAuthorsGrid() is called from the windows form i.e. PopulateAuthorsDataGrid

Can you see why I get this error:
can't create a child list for field authors.
The datagrid does not expand, I have to click on the plus sign to expand it.

Thank you


Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

PopulateAuthorsDataGrid()
End Sub


'This procedure calls the clsDataSet to return a dataset for the datagrid...
Private Sub PopulateAuthorsDataGrid()
Dim oDataset As clsDataSet

Try
oDataset = New clsDataSet()

DataGrid1.DataSource = oDataset.PopulateAuthorsGrid()
DataGrid1.DataMember = "authorts"

Catch oEx As Exception
MessageBox.Show(oEx.Message)
End Try
End Sub

'clsDataSet...
Public Function PopulateAuthorsGrid() As DataSet

Dim da As SqlDataAdapter
Dim ds As DataSet
Dim oCon As SqlConnection
Dim strSQL As String

strSQL = "SELECT au_lname, au_fname, title, price"
strSQL &= " FROM authors"
strSQL &= " INNER JOIN titleauthor ON authors.au_id = titleauthor.au_id"
strSQL &= " INNER JOIN titles ON titleauthor.title_id = titles.title_id"
strSQL &= " ORDER BY au_lname, au_fname"

Try
oCon = New SqlConnection(ConnectToDB)
da = New SqlDataAdapter(strSQL, oCon)

ds = New DataSet()
oCon.Open()
da.Fill(ds, "authors")
oCon.Close()
Catch
Throw
End Try

Return ds
End Function