Hi Paul,

To explain whats happening: A variant containing an array (or a range) is
not the same as an array of variants.

If you want to access the parameter as a variant array just assign it to a
variant.

Public Function GoodBadFunction(avVariant As Variant) As Variant
Dim vVar As Variant
Debug.Print TypeName(avVariant)
vVar = avVariant
Debug.Print TypeName(vVar)
GoodBadFunction = vVar
Debug.Print TypeName(GoodBadFunction)
End Function

What happens is that when a variant parameter is passed a range, the variant
is treated as containing a range,
and when that variant containing a range is assigned to another variant, the
range is converted to a variant containing an array of variants.
(the exact treatment differs slightly by VBA version).
However Excel will not let you pass a range to a variant array parameter
(avVariant() as variant).

This is also important for performance reasons:
converting a range to a variant containing an array of variants with a
single assignment statement is very efficient compared to reading the
elements of the range one--by-one,
but if you only want a few elements of the range (typically things like
binary search or excel functions like MATCH and VLOOKUP) then it is much
faster not to assign it to a variant but to handle it as a variant
containing a range.

I assume that using a paramarray involves each individual parameter being
handled internally as a variant which is then assigned to a single element
(as an array of variants) of the variant array that the function sees. so
the paramarray winds up as an array of variants each element of which can
contain an array.

Charles
______________________
Decision Models
FastExcel Version 2 now available.
www.DecisionModels.com

"Charles Williams" wrote in message
...
It works OK if you use as variant rather than as variant(), and also
handles
non-range arguments.

Public Function GoodBadFunction(avVariant as Variant) as String
goodBadFunction= TypeName(avVariant)
End Function

regds
Charles
______________________
Decision Models
FastExcel Version 2 now available.
www.DecisionModels.com

"Paul S Bryant" wrote in message
om...
I agree that the elements in the Variant() array in the GoodFunction()
are indeed of type Range. This wouldn't help me pass data to DotNet
without the PIA, but it does confirm the thing I am immediately
interested in. That is, the Excel function bar can't pass parameters
to functions requiring variant arrays unless you use the ParamArray
modifier.


"Tom Ogilvy" wrote in message
...
I believe your interpretation of GoodFunction is incorrect. If you
test
the typename of the first element of avVariant, it will be Range. No
conversion has taken place. Replace the argument with a single
number,
and
as written you will get the same result.

=GoodFunction(21)


Your interpretation of BadFunction is correct in that you have a
mismatch
with argument type and the function is never entered.