Filter Combo box with Text box

Question

Hello,
I'm searching the solution whole day,  I'm trying to make a task management database where there is a combo box field (status) for choosing status "not started" "in progress" "paid" "not paid" I also have a Field (not a combo box) Which is called Purchase order. 
My point is  IF Purchase Order field is null I want to filter Combo box  to limit the user not to choose "paid" so there will be a list  "not started" "in progress"  "not paid", If purchase order field is filled with data  I want combo box to show full list not to hide the "paid".

I cant make a relationship with Purchase order and Status 
Is there any solution? 
Thank you in advance.

Answer 1

Hi,

If you're using a lookup field at the table level, you should consider changing it to a regular textbox. I think to get what you want, you can set the Row Source property of a combobox on a form using its GotFocus event. For example, you might try something like:

Me.ComboboxName.RowSource = "Not Started;In Progress" & IIf(IsNull([Purchase Order]), ";Paid", "") & ";Not Paid"

Hope it helps...