When you move between supplier records on a Suppliers form, you might want to see the products each supplier carries in a Products form. In the Form_Current event procedure of the Suppliers form, set the FilterOn and Filter properties of the Products form:
Private Sub Form_Current()
' Declare and set a variable to store the WHERE
' clause that describes the records you want to
' display.
Dim strCond As String
strCond = "SupplierID = Forms!Suppliers!SupplierID"
' Use the IsLoaded function from the Northwind
' sample database to check whether the Products
' form is open, then set the properties.
If IsLoaded("Products") Then
Forms![Products].FilterOn = True
Forms![Products].Filter = strCond
End If
End Sub