Checking for Null value

[Neil.Cranston]

I am using Access 97 and have a form with a combo box on it. I want to be able to check that a value has been selected fron the combo box before a button is used to select another from.
I have been trying this code but somthing is going wrong, which I don't fully understand. I have placed it inside the code for the button.

if len(cmbContract) < 0 then
msgbox "the contract number has not been selected"
exit sub
end if

any one got a suggestion how to do this.

Neil

 

[Geoff Codd]

Try this

if isnull (cmbContract) then
msgbox "the contract number has not been selected"
else
Enter the procedure that should take place if a value is selected

exit sub
end if