System.NullReferenceException - AskIdSymbolInfo - NX4 VB.NET App

[MarckyMON]

Hi everyone,

I am currently developing a function which counts the number of all round ID symbols containing specific text. Since the NX4 NX/Open VB.NET API does not contain an IDSymbol object, I am using the UG/Open wrapper functions instead:

Dim idSymbolType As UFDrf.IdSymbolType
Dim idSymbolOrigin() As Double = {0.0, 0.0, 0.0}
Dim idSymbolInfo() As UFDrf.IdSymbolInfo

ufSession.Drf.AskIdSymbolInfo(idSymbolTag, idSymbolType, idSymbolOrigin, idSymbolInfo)

When running the program, it terminates with a System.NullReferenceException when trying to call AskIdSymbolInfo. Here is the snippet from the log file:

System.NullReferenceException: Object reference not set to an instance of an object.
at NXOpen.UF.UFDrf.AskIdSymbolInfo(Tag id_symbol_tag, IdSymbolType& id_symbol_type, Double[] id_symbol_origin, IdSymbolInfo[]& id_symbol_info)
at TDF_MIKRON_change_table.ChangeTable.CountIDSymbols(Part workPart, String idText)
at TDF_MIKRON_change_table.EntryPoint.Main()
*** EXCEPTION: Error code 67 in line 996 of O:\ugnx404\ip2\src\syss\no\ind\lmldr.c at Tue Dec 07 21:34:33 2010 W. Europe Standard Time
+++ Object reference not set to an instance of an object.

I'm not sure where the problem is, but my hunch is it has something to do with the variable declaration:

Dim idSymbolInfo() As UFDrf.IdSymbolInfo

I'm really at a loss here and any help is much appreciated. Thanks!

 

[daluigi]

Could you publish the complete code so we've a chance to locate the problem?

 

[MarckyMON]

Hi daluigi,

Here is the function:

    Public Shared Function CountIDSymbols(ByVal workPart As Part, ByVal idText As String) As Integer
        CountIDSymbols = 0

        Dim idSymbolTag As Tag = Tag.Null
        Dim objType, objSubtype As Integer

        Do
            ufSession.Obj.CycleObjsInPart(workPart.Tag, UFConstants.UF_drafting_entity_type, idSymbolTag)

            If Not idSymbolTag.Equals(Tag.Null) Then
                ufSession.Obj.AskTypeAndSubtype(idSymbolTag, objType, objSubtype)

                If objSubtype.Equals(UFConstants.UF_draft_id_symbol_subtype) Then
                    Dim idSymbolType As UFDrf.IdSymbolType
                    Dim idSymbolOrigin() As Double = {0.0, 0.0, 0.0}
                    Dim idSymbolInfo() As UFDrf.IdSymbolInfo 
                    ufSession.Drf.AskIdSymbolInfo(idSymbolTag, idSymbolType, idSymbolOrigin, idSymbolInfo)

                End If

            End If

        Loop Until idSymbolTag.Equals(Tag.Null)
    End Function

 

[MarckyMON]

Hey, I'm really stuck here and any help would be appreciated. Doesn't anyone have an idea???

Marc
NX Software Developer

 

[MarckyMON]

I have an update on the issue.

Previously, I had NX 4.0.4.2.
I've updated to NX 4.0.4.2 MP10, but now I have a new error message (see below). Apparently, the NX/Open library of NX4 cannot be trusted at all! Has anyone here encountered such an error? Is there a work around for this? I don't want to start my program all over just so I can get it working in C... :/

Caught exception while running: Main
System.ArgumentException: Type _LeaderInfo can not be marshaled as an unmanaged structure; no meaningful size or offset can be computed.

at System.Runtime.InteropServices.Marshal.SizeOf(Type t)

at NXOpen.UF.UFDrf.AskIdSymbolInfo(Tag id_symbol_tag, IdSymbolType& id_symbol_type, Double[] id_symbol_origin, IdSymbolInfo[]& id_symbol_info)

at TDF_MIKRON_change_table.ChangeTable.CountIDSymbols(Part workPart, String idText)

at TDF_MIKRON_change_table.EntryPoint.Main()
*** EXCEPTION: Error code 67 in line 996 of F:\workdir\reference\NX404_2\src\syss\no\ind\lmldr.c at Fri Dec 10 00:55:05 2010 W. Europe Standard Time
+++ Type _LeaderInfo can not be marshaled as an unmanaged structure; no meaningful size or offset can be computed.
[ 1] 75C99617 (KERNELBASE)

Thanks!

Marc
NX Software Developer