Forms :: Filtering A Combo Box On A Subform From A Combo Box On A Main Form

I have a Suppliers database which contains a form that will allow me to place orders with Suppliers.The Main form has a combo box that allows me to select the supplier. The combo box is called SupplierID with the following:

Row source: SELECT Suppliers.SupplierID, Suppliers.CompanyName FROM Suppliers ORDER BY Suppliers.CompanyName;

The subform is called Stock Subform witha combo box called ProductID with the following:

Row source: SELECT DISTINCT Products.ProductID, Products.ProductName, Suppliers.CompanyName, Products.Discontinued FROM Suppliers INNER JOIN Products ON Suppliers.SupplierID=Products.SupplierID WHERE (((Products.Discontinued)=0)) ORDER BY Products.ProductName;
Event Procedure - AfterUpdate: Private Sub ProductID_AfterUpdate()
On Error GoTo Err_ProductID_AfterUpdate
Dim strFilter As String
' Evaluate filter before it's passed to DLookup function.
strFilter = "ProductID = " & Me!ProductID

[code]..

The Link fields are done on the Purchase Order ID (PONoID).What I want to achieve is to select the supplier from the combo box (SupplierID) on the main form and then the combo box (ProductID) on the subform to filter to only show products directly supplied by the Supplier selected on the Main Form.