ACC: "Undefined Function" Error Referencing Combo Box Column

• Microsoft Access versions 2.0, 7.0, 97

SYMPTOMS

Moderate: Requires basic macro, coding, and interoperability skills.

In Microsoft Access, you may receive the following error message if you refer to the Column property of a combo box in a query's criteria row (query by form):

   Undefined function '[Forms]![FormName]![ComboBoxName].[Column]' in
   expression.

CAUSE

Microsoft Access tries to parse the criteria expression at the "(" (opening parenthesis). When doing so, Microsoft Access concludes that the unbroken string preceding the "." (period) (and returned within single quotation marks in the error message) is a user-defined function. Because Microsoft Access finds no such function in any of your modules, you receive the "Undefined function" message.

RESOLUTION

Wrap the entire reference as a text string inside an Eval() function. This tells Microsoft Access to consider the entire reference as a whole and not to attempt to parse it.

For example, to refer to the first (left-most) column of a combo box in the Criteria row of the QBE grid, use the following syntax.

   Eval("[Forms]![FormName]![ComboBoxName].[Column](0)")