Thanks! I got it to work by changing the syntax to
If IsNull([odometer_start]) And IsNull([length_of_trip]) Then
as Bob suggested. Why is that? The odometer_start and length of trip returned null values when I stepped thru the code they are numeric fields.
Thanks again for your help!
I have a button to calculate trip information. I can't get the message box to pop up in the following code. Can anyone tell me why?
If [odometer end] and [odometer start] are null and I click the calculate button nothing happens, I want the message box to appear.
here is the code I am using...
I have created a user input form with three input fields [a], [b] and [c]. I want the user to populate any two of the three fields then have the third field be caculated based on the user's input [c]=[a]-[b], [a]=[b]-[c] and [b]=[a]-[c]. I would love to not have the form validate until two of...