error 424

[Orcanut]

In an on click event the following:
"If Forms![Guests]![Guests Subform].Form![CheckOutDate] Is Null Then" elicits a runtime error 424 message.

In the same procedure &quot;If Forms![Guests]![Guests Subform].Form![Amount Due].Value <> 0 Then&quot; runs properly.

Could anyone explain what is wrong with the first line.

Thanks.

 

[essnrv]

Try this
if IsNull(Forms![Guests]![Guests Subform].Form![CheckOutDate]) Then Please remember to give helpful posts the stars they deserve!
This makes the post more visible to others in need!

 

[Orcanut]

Thank you this works fine. Is the syntax **** Is null therefore wrong in all cases or when should I not use it?

 

[essnrv]

I didn't Understand your question.Below is the explanation for Isnull function

'If CheckOutDate is null
if IsNull(Forms![Guests]![Guests Subform].Form![CheckOutDate]) Then
'Write a code to execute
end if
'If you want to check for Not null
if Not IsNull(Forms![Guests]![Guests Subform].Form![CheckOutDate]) Then
'Write a code to execute
end if

Hope I answered your question Please remember to give helpful posts the stars they deserve!
This makes the post more visible to others in need!

 

[DonQuichote]

The syntax

... Is Null

is a combination of two things:
Null is a special Variant Data type, but not an object.
the

Is

keyword says if two objects are the same. That is, the same instance.

I think that, due to Null propagation,

... Is Null

will never return

true

or

false

, but always

Null

.

Best regards

 

[Orcanut]

Many thanks.