Chip, Bernie,

Many thanks for the input. I tried both using double paentheses and using
ByRef. The result remains. the same.
Just for fun I created a new function with the parameter defined as object
to see what the type of parameter the function receives:

Public Function MyTest(ByVal MyNumber As Object) as Double
Dim n As Double = 0
Try
n = DirectCast(MyNumber, Double)
Catch ex As Exception
MsgBox("Type=" & MyNumber.GetType.ToString()
End Try
Return n / 2
End Function

It turns out that MyNumber is of type "System.__ComObject"...

I'm really puzzled...

What is the best way to debug in this case? As I understand I have to
compile the solution, install it and then load it in Excel in order to
use/test it, so I see no way to get into debug mode...

Thanks again & kind regards,
Etienne


"Chip Pearson" wrote in message
...
I can't reproduce the problem. I created a NET Class Library exactly
as described on the web page and the Divide functions work with both
static values =DivideBy2(100) or with cell references
=DivideBy2($A$1). Have you tried debugging the code in VS? Just out
of curiosity, try calling the functions as

=DivideBy2(($A$1))

The inner parentheses should cause Excel to evaluate A1 before passing
it to the Divide2 function.

Beyond that, I don't know why it would return an error.


Cordially,
Chip Pearson
Microsoft Most Valuable Professional
Excel Product Group, 1998 - 2009
Pearson Software Consulting, LLC
www.cpearson.com
(email on web site)


On Wed, 11 Mar 2009 13:08:29 +0100, "Etienne-Louis Nicolet"
wrote:

I'm playing with a sample found on
http://www.cpearson.com/Excel/Creati...nctionLib.aspx . My idea is to
create a class library in VB.NET 2008 that I can use as automation add-in
in
Excel.

In the following code snippet the function 'DivideBy2' has a parameter of
type Double.
- When passing a number as parameter e.g. "=DivideBy2(50)", I get a
correct
result.
- If I pass a cell reference as paramter e.g. "=DivideBy2($A$1)", I get a
"#Value" error ("A value used in the formula is of the wrong type"

Could anybody give me a hint how to solve this problem?

Many thanks for your suggestions,
Etienne

Here's the code:

<ClassInterface(ClassInterfaceType.AutoDual), ComVisible(True)Public
Class
SampleFunctions

Public Function DivideBy2(ByVal pDouble As Double) As Double

Return pDouble / 2

End Function

<ComRegisterFunctionAttribute()Public Shared Sub RegisterFunction(ByVal
pType As Type)

Registry.ClassesRoot.CreateSubKey(GetSubkeyName(pT ype))

End Sub

<ComUnregisterFunctionAttribute()Public Shared Sub
UnregisterFunction(ByVal pType As Type)

Registry.ClassesRoot.DeleteSubKey(GetSubkeyName(pT ype), False)

End Sub

Private Shared Function GetSubkeyName(ByVal pType As Type) As String

Dim S As New System.Text.StringBuilder()

S.Append("CLSID\{")

S.Append(pType.GUID.ToString().ToUpper())

S.Append("}\Programmable")

Return S.ToString()

End Function

End Class