how would i write this if null function?

[RLehrbass]

When i close the form, If the company Name field is 'empty' then fill it in with the First and Last name.

i would think it would be something like this?

If Null Me![CompanyName] then
Me![CompanyName] = Me![FirstName] &" "& Me![LastName]
End If

[June7]

If IsNull(Me!CompanyName) Then

[ItsMe]

You could use the IsNull() function and also check for an empty string ...

If IsNull(Me![CompanyName]) or Me![CompanyName] = "" then
 Me![CompanyName] = Me![FirstName] & " " & Me![LastName]
 End If

Another approach may be to look for something greater than an empty string. You might want to test the following ...

If Me![CompanyName] > "" then
else
Me![CompanyName] = Me![FirstName] & " " & Me![LastName]
 End If

[RLehrbass]

Does this look correct?

If IsNull (Me!CompanyName) Then
Me![CompanyName] = Me![FirstName] & " " & Me![LastName]
End If

[ItsMe]

Does this look correct?

Sometimes controls can contain empty strings so it is a good idea to test for them. Newer versions of Access will do some Black Box stuff and turn fields assigned Empty Strings into Null. However, a control can still = "" (at times)