Forms :: Storing Value In Another Text Box Populated From A Combo Box In A Form

How does one store the value derived from a combo box to another text box in a form?E.g. Supplier name is a combo box. The combo box has 2 columns, supplier and supplier ID.the supplier name stores the supplier in its own text box.When you select the supplier, the supplierID appears in another text box.I need to store this supplier ID.The control source is =[suppliername].[column](1) When I look up the table, the supplier is captured in the supplier name but the supplierID is not captured in the supplier ID field.