I have searched for days and not been able to find an answer to a supposedly easy question.

I have a continuous form "Entry_Form" based off a table called "Today". I want to add additional criteria to the table using the form and have created a combo box that is based on a separate table called "Reason_Codes". "Reason Codes" has two fields "ID" and "Description".

When selecting the combo box "ID_Selector" I populate one of the fields on the form which then populates the corresponding field on the table. This works.

My problem is that I want to have a text box on the form called "Description_Code" populated automatically the "Description" based the ID chosen.

I have created the following DLookUp equation and placed it into the Control Source, but nothing is populated in the "Description_Code" field.

=DLookUp("[Description]","[Reason_Codes]","[ID] = Forms![Entry_Form]!ID_Selector")

Needless to say, I have tried dozens of varieties, but to no avail. Is DLookUp the proper function? What am I doing wrong?

Any help would be greatly appreciated.

Try:

=DLookUp("[Description]","[Reason_Codes]","[ID]=" & Forms![Entry_Form]!ID_Selector)

Note that if your ID field is TEXT, rather than numeric, you will need:

=DLookUp("[Description]","[Reason_Codes]","[ID]='" & Forms![Entry_Form]!ID_Selector & "'")

Unfortunately that did not work. It gives the #Name? operator expression.

The syntax is correct for the controlsource of a control (and for a Dlookup), so we need to figure out why it isn't working in your form.

If you hard-code in an ID, does it return a value? For example:

=DLookUp("[Description]","[Reason_Codes]","[ID]=1")

(assuming 1 is a valid ID). If so, we need to look at the Forms![Entry_Form]!ID_Selector portion. Is the form open? Is the spelling all correct?

Honestly, if you already have a combo box to pull the ID, it might be a lot simpler to simply add the Description column to your combo box and have it display both columns (although remaining bound to only the ID column).