I have datawindows in which I want computed fields to sometimes evaluate to
NULL.
I have not found a constant that I can use in expressions that is NULL so
how do I specify the NULL-value?
In PowerBuilder a datawindow expression can call a "global function" so I
can use that to return a NULL (e.g. "gf_NullString()") - but in DW.NET 1.0
we unfortunately (currently) don't have any such option.
I have found a way of getting NULL-values by using the fact that the
Date()-function returns a NULL if the string is an invalid date.
Since NULL propagates we can use that to return NULL-Strings by using
"String(Date('null')))" and NULL-Longs (Integer in .NET) by using
"Long(String(Date('null')))". But it is a little awkward. Does anyone now of
a more straightforward way of getting a NULL in an expression in a
datawindow in DataWindow .NET 1.0 ?

Best regards
Lars
Sweden