ACC2000: List Box Column Property Receives Incorrect Row Information

When you select a row from a multicolumn list box or combo box, controls that reference the Column property of the list box or combo box retrieve data from a different row in the list box or combo box.

NOTE: A list box may appear to work as expected, but when you bind the list box, it exhibits the same behavior as a combo box.

This behavior occurs because the list box or combo box's BoundColumn property does not point to a field with unique values.

The list box or combo box's BoundColumn property must point to a field that contains unique values. If the BoundColumn property does not point to a field with unique values, Microsoft Access returns information for the first row with a matching BoundColumn value when you select a row in the list box or combo box.

For example, the Type field in the sample table below does not contain unique values. If the Type field is used for the BoundColumn property, a text box referencing the second column returns "Apple" rather than "Grape" when you select the third row.

If you use the Description column for the BoundColumn property, this behavior does not occur because the Description column contains unique values.

Another way to resolve this behavior is to add an AutoNumber field to the underlying table, and then use the AutoNumber field for the BoundColumn property.

You can also use the ListIndex property of the combo box or list box to reference the selected row in the combo box or list box. Microsoft Access sets the ListIndex property value when an item is selected in a list box or list box portion of a combo box. The ListIndex property value of the first item in a list is 0, the value of the second item is 1, and so on. The code below refers to the example listed in the "More Information" section of this article. You can add this code to the AfterUpdate property of the combo box: NOTE: If you use this code, remove the expressions that are assigned to the ControlSource properties of the Stock Number and Description controls.

Note that the ListIndex property value can be accessed indirectly by setting the BoundColumn property of a combo box or a list box to 0. If the BoundColumn property is set to 0, the underlying table field to which the combo box or list box is bound contains the same value as the ListIndex property setting.

Steps to Reproduce Behavior

1. If you are working with Microsoft Access database, create the following table:
   Table: Table1
   
   Field Name: Manufacturer
   Data Type: Text
   
   Field Name: Stock Number
   Data Type: Number
   Field Size: Long Integer
   Indexed: Yes
   
   Field Name: Description
   Data Type: Text
   
   Table1 Properties:
   Primary Key: Stock Number
   If you are working with Microsoft Access project, create the following table:
   Table: Table1
   
   Field Name: Manufacturer
   Data Type: Text
   
   Field Name: Stock Number
   Data Type: Int
   Allow Nulls: No
   
   Field Name: Description
   Date Type: Text
   
   Table1 Properties:
   Primary Key: Stock Number
2. View the table in Datasheet view. Add the following data to the table:

   Manufacturer   Stock Number   Description
   -----------------------------------------
   IB Co          1              Mouse
   IB Co          2              Printer
   IB Co          3              Hard Drive
   ComCo          4              PC
   					

3. Create the following new form:
   Form: Test1
   
   Combo box:
   Name: Manufacturer
   ControlSource: <leave empty>
   RowSourceType: Table/Query
   RowSource: Table1
   ColumnCount: 3
   BoundColumn: 1
   Width: 3
   
   Text box:
   Name: Stock Number
   ControlSource: =[Manufacturer].Column(1)
   
   Text box:
   Name: Description
   ControlSource: =[Manufacturer].Column(2)
4. View the form in Form view.
5. Select the first row in the combo box.
   
   Note that the Stock Number and Description boxes correctly display "1" and "Mouse."
6. Select the third row in the combo box.
   
   Note that the Stock Number and Description boxes still display the information from the first row.
7. Select the fourth row in the combo box.
   
   Note that the Stock Number and Description boxes display the correct information for the fourth row.

If you change the BoundColumn property of the Manufacturer list box to 2 instead of 1, the text boxes on the form display the correct information for all the rows in the list box because the second column contains unique values.

For more information about combo boxes, click Microsoft Access Help on the Help menu, type combo boxes: what they are and how they work in the Office Assistant or the Answer Wizard, and then click Search to view the topic.

For more information about the ListIndex property, click Microsoft Access Help on the Help menu, type listindex property in the Office Assistant or the Answer Wizard, and then click Search to view the topic.