Expressions in Access 2007

[Melissa Comerfo]

I am trying to write an expression where if a certain field is answered NO than another filed automatically populates Null or N/A. Can anybody help me? Thanks

[NeoPa]

Populating another control (which is what you mean) is done most easily by setting the Default Value. As you only stipulate one logical situation, clearing the Default Value (so it's Null) would do you.

If your question makes more sense than it sounds, then you really need to ask the question you actually need an answer to.

[Melissa Comerfo]

Let me try to explain it differently. If field A is answered no then I want field B to be auto-populated to say NULL. Sometimes field A will be yes and I will need to fill in field B with information. Does that make more sense?

[NeoPa]

Tell me if the following explains your situation accurately :
[FieldA] is a Boolean which can take Yes or No as values.
When [FieldA] is Yes, whether it has been changed to that in the form or it was a pre-existing value from the record, [FieldB] should be set to Null as well as being locked so that the operator cannot change it.
When [FieldA] is No, whether it has been changed to that in the form or it was a pre-existing value from the record, [FieldB] should be unlocked so that the operator can enter a value in should they wish.

PS. Please also explain the control type used for [FieldA] on your form. I guess it's probably a CheckBox, but require confirmation.

[Melissa Comerfo]

[Field A] is a look-up (text) field with a possible answer of yes or no. If I select yes I want [Field B] to gray out, say Null, N/A (any of those would work). If I answer yes to [Field A] I just want to type information into [Field B]. So that when I go back to my database it does not look like I have empty boxes that need to be completed

[NeoPa]

Melissa, I found your explanations incomplete logically, hence I asked a clear yes/no question. I really need such a straightforward answer to enable me to continue. If you feel that my explanation is quite close but not quite on the button, please give a Yes but, with a qualifier explaining the exact difference. Otherwise either Yes or No is required.

The question in the PS is answered however, as you mention the control is a TextBox. We can at least progress with this.

It seems extraordinary to me that a boolean value is treated as a string. This means that you must have (and I need you to tell me all about how you configured it.) set up the control such that other values are blocked. In case you're interested, the normal way to manage a boolean value on a form is to use a CheckBox control. CheckBox controls have values of TRUE or FALSE only. TextBoxes have string values instead. Entirely inappropriate for booleans and not as straightforward to manage.