ANY COM Interop GURUS out there!? - Nested Structs with arrays of

[Aaron]

I've got a doozie of a problem! I and others have been trying to figure this
out for too long and I've come to the conclusion that I should probably look
for some support..

Ok, I have a COM component written in C++ (I don't have the source just the
binary) and am referencing it from VB. I would say about 99% of the
functionality exposed by this COM component works fine from vb .net but I am
having a problem calling a method which has a parameter that is a struct
defined in the COM component. This struct has a member which is a struct
which contains an array of another struct. When I call the method I receive a
TypeLoadExcepti on with very little detail (thats about it) Here is the MSIL
for the structures.. The members who are causing the problems (i am about 99%
sure) are the members that end in "list"

'I have removed all of the members of the following struct who I feel are
defined correctly (i removed about 19 members of this struct). This is done
for the sake of simplicity

..class public sequential ansi sealed beforefieldinit tcsGroupAttribu tes_t
extends [mscorlib]System.ValueTyp e
{
..pack 4
..size 0
..field public valuetype Nokia.TCSapi.tc sSubscriberAddr ess_t groupAddress
..field public valuetype Nokia.TCSapi.tc sOrgBlockAttrib utes2List_t
entryRightsList //THIS GUYS THE PROBLEM! 99% SURE!
} // end of class tcsGroupAttribu tes_t

' Here is the definition of tcsOrgBlockAttr ibutes2List
..class public sequential ansi sealed beforefieldinit
tcsOrgBlockAttr ibutes2List_t
extends [mscorlib]System.ValueTyp e
{
..pack 2
..size 0
..field public unsigned int16 length
..field public marshal( fixed array [75]) valuetype
Nokia.TCSapi.tc sOrgBlockAttrib utes2_t[] orgBlockAttribu tes2List
} // end of class tcsOrgBlockAttr ibutes2List_t

'Here is the definition of tcsOrgBlockAttr ibutes2_t

..class public sequential ansi sealed beforefieldinit tcsOrgBlockAttr ibutes2_t
extends [mscorlib]System.ValueTyp e
{
..pack 2
..size 0
..field public marshal( fixed array [6]) unsigned int16[] orgBlockId
..field public marshal( fixed array [32]) unsigned int8[] orgBlockMnemoni c
} // end of class tcsOrgBlockAttr ibutes2_t

Ok, Here is the signature of the method that I am calling
(tcsGroupAttrib utesMask structure is straightforward and similiar objects
work in other calls so this structure is not the problem. Its the
tcsGroupAttribu tes)

..method public hidebysig newslot abstract virtual
instance int32 Create([in] valuetype Nokia.TCSapi.tc sGroupAttribute s_t&
groupAttributes ,
[in] valuetype Nokia.TCSapi.tc sGroupAttribute sMask_t& groupAttributes Mask,
[in] int16 cookie) runtime managed internalcall
{
}

This is an incredibley difficult problem and much respect to anyone that can
help or solve this. I have googled the ** out of this and have read nearly
every resource out there discussing COM interop. I have tried editing the
disassembled il and setting the member valuetypes to IntPtrs but then I get a
MissingFieldExc eption.. Appreciate any help in advance!

Aaron

[Mattias Sjögren]

Aaron,

This struct has a member which is a struct
which contains an array of another struct.

That's unfortunately not supported by the marshaler. See

http://dotnetinterop.com/faq/?q=StructWithStructArray

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Aaron]

First of all, thanks for the response Mattias! I notice you consistently
help us problem ridden posters and let me just say we really appreciate the
time you take helping us.

Regarding my issue, I don't have the source code for the COM component so am
unable to change the type definitions for the Struct members. This dll does
not export these methods either, so, if I understand PInvoke correctly, I am
unable to use PInvoke since the method isn't exported. So, knowing what I
know now from the info contained in the link you referred to, if I were able
to flatten the struct members (get rid of array references, which I would
like to do anyways since I am always just passing in 1) this method would
complete S_OK. <- :s

So the question now is, is it possible to _redefine_ a structure which is
declared in the namespace of the COM component? So I would be able to call
'pseudo code
Structure MyNewlyRedefine dGroupAttribute
....
.... ' redefine the array structure to be non-arrays
end structure
Dim myNewlyRedefine dGroupAttribute s as MyNewlyRedefine dGroupAttribute

Be able to use my redefined flattened structure without getting
"There is no interface that accepts these parameters
(myapp.MyNewlyR edefinedGroupAt tribute, Nokia.TCSapi.tc sGroupAttribute sMask_t,
int16)"

Create(myNewlyR edefinedGroupAt tributes, groupAttributes Mask, cookie)

Is it possible to just edit the IL and reassemble or will I get that
"missingfieldex ception"?

Thanks in advance Mattias!

Aaron
"Mattias Sjögren" wrote:

Aaron,

This struct has a member which is a struct
which contains an array of another struct.

That's unfortunately not supported by the marshaler. See

http://dotnetinterop.com/faq/?q=StructWithStructArray

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Aaron]

In other words, how do I go about _flattening_ my structure when I don't have
the source code for the COM component to change the c++ source and do a
recompile. Can I do something with the IL or a switch to the TLBIMP.exe? Any
help appreciated!

"Aaron" wrote:

First of all, thanks for the response Mattias! I notice you consistently
help us problem ridden posters and let me just say we really appreciate the
time you take helping us.

Regarding my issue, I don't have the source code for the COM component so am
unable to change the type definitions for the Struct members. This dll does
not export these methods either, so, if I understand PInvoke correctly, I am
unable to use PInvoke since the method isn't exported. So, knowing what I
know now from the info contained in the link you referred to, if I were able
to flatten the struct members (get rid of array references, which I would
like to do anyways since I am always just passing in 1) this method would
complete S_OK. <- :s

So the question now is, is it possible to _redefine_ a structure which is
declared in the namespace of the COM component? So I would be able to call
'pseudo code
Structure MyNewlyRedefine dGroupAttribute
...
... ' redefine the array structure to be non-arrays
end structure
Dim myNewlyRedefine dGroupAttribute s as MyNewlyRedefine dGroupAttribute

Be able to use my redefined flattened structure without getting
"There is no interface that accepts these parameters
(myapp.MyNewlyR edefinedGroupAt tribute, Nokia.TCSapi.tc sGroupAttribute sMask_t,
int16)"

Create(myNewlyR edefinedGroupAt tributes, groupAttributes Mask, cookie)

Is it possible to just edit the IL and reassemble or will I get that
"missingfieldex ception"?

Thanks in advance Mattias!

Aaron
"Mattias Sjögren" wrote:

Aaron,

This struct has a member which is a struct
which contains an array of another struct.

That's unfortunately not supported by the marshaler. See

http://dotnetinterop.com/faq/?q=StructWithStructArray

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Aaron]

One last thing.. Does anyone know what the pack and size attributes represnt?

..class public sequential ansi sealed beforefieldinit
tcsOrgBlockAttr ibutes2List_t
extends [mscorlib]System.ValueTyp e
{
.pack 2
.size 0
.field public unsigned int16 length
.field public marshal([ + 0]) valuetype
Nokia.TCSapi.tc sOrgBlockAttrib utes2_t[] orgBlockAttribu tes2List
} // end of class tcsOrgBlockAttr ibutes2List_t
In addition, I just want this call to the COM component to work, no matter
how hackey it is. I can make it pretty l8r.

"Aaron" wrote:

I've got a doozie of a problem! I and others have been trying to figure this
out for too long and I've come to the conclusion that I should probably look
for some support..

Ok, I have a COM component written in C++ (I don't have the source just the
binary) and am referencing it from VB. I would say about 99% of the
functionality exposed by this COM component works fine from vb .net but I am
having a problem calling a method which has a parameter that is a struct
defined in the COM component. This struct has a member which is a struct
which contains an array of another struct. When I call the method I receive a
TypeLoadExcepti on with very little detail (thats about it) Here is the MSIL
for the structures.. The members who are causing the problems (i am about 99%
sure) are the members that end in "list"

'I have removed all of the members of the following struct who I feel are
defined correctly (i removed about 19 members of this struct). This is done
for the sake of simplicity

.class public sequential ansi sealed beforefieldinit tcsGroupAttribu tes_t
extends [mscorlib]System.ValueTyp e
{
.pack 4
.size 0
.field public valuetype Nokia.TCSapi.tc sSubscriberAddr ess_t groupAddress
.field public valuetype Nokia.TCSapi.tc sOrgBlockAttrib utes2List_t
entryRightsList //THIS GUYS THE PROBLEM! 99% SURE!
} // end of class tcsGroupAttribu tes_t

' Here is the definition of tcsOrgBlockAttr ibutes2List
.class public sequential ansi sealed beforefieldinit
tcsOrgBlockAttr ibutes2List_t
extends [mscorlib]System.ValueTyp e
{
.pack 2
.size 0
.field public unsigned int16 length
.field public marshal( fixed array [75]) valuetype
Nokia.TCSapi.tc sOrgBlockAttrib utes2_t[] orgBlockAttribu tes2List
} // end of class tcsOrgBlockAttr ibutes2List_t

'Here is the definition of tcsOrgBlockAttr ibutes2_t

.class public sequential ansi sealed beforefieldinit tcsOrgBlockAttr ibutes2_t
extends [mscorlib]System.ValueTyp e
{
.pack 2
.size 0
.field public marshal( fixed array [6]) unsigned int16[] orgBlockId
.field public marshal( fixed array [32]) unsigned int8[] orgBlockMnemoni c
} // end of class tcsOrgBlockAttr ibutes2_t

Ok, Here is the signature of the method that I am calling
(tcsGroupAttrib utesMask structure is straightforward and similiar objects
work in other calls so this structure is not the problem. Its the
tcsGroupAttribu tes)

.method public hidebysig newslot abstract virtual
instance int32 Create([in] valuetype Nokia.TCSapi.tc sGroupAttribute s_t&
groupAttributes ,
[in] valuetype Nokia.TCSapi.tc sGroupAttribute sMask_t& groupAttributes Mask,
[in] int16 cookie) runtime managed internalcall
{
}

This is an incredibley difficult problem and much respect to anyone that can
help or solve this. I have googled the ** out of this and have read nearly
every resource out there discussing COM interop. I have tried editing the
disassembled il and setting the member valuetypes to IntPtrs but then I get a
MissingFieldExc eption.. Appreciate any help in advance!

Aaron

[tcarvin]

Couldn't you just alter the typelib for your COM component? You can use a tool
like OLE View to extract the type lib from the COM component, which you could
then modify and rebuild. Be forewarned, I haven't tried this specifically.

Tom

"Aaron" <Aa***@discussi ons.microsoft.c om> wrote in message news:<35******* *************** ************@mi crosoft.com>...

In other words, how do I go about _flattening_ my structure when I don't have
the source code for the COM component to change the c++ source and do a
recompile. Can I do something with the IL or a switch to the TLBIMP.exe? Any
help appreciated!

"Aaron" wrote:

First of all, thanks for the response Mattias! I notice you consistently
help us problem ridden posters and let me just say we really appreciate the
time you take helping us.

Regarding my issue, I don't have the source code for the COM component so am
unable to change the type definitions for the Struct members. This dll does
not export these methods either, so, if I understand PInvoke correctly, I am
unable to use PInvoke since the method isn't exported. So, knowing what I
know now from the info contained in the link you referred to, if I were able
to flatten the struct members (get rid of array references, which I would
like to do anyways since I am always just passing in 1) this method would
complete S_OK. <- :s

So the question now is, is it possible to _redefine_ a structure which is
declared in the namespace of the COM component? So I would be able to call
'pseudo code
Structure MyNewlyRedefine dGroupAttribute
...
... ' redefine the array structure to be non-arrays
end structure
Dim myNewlyRedefine dGroupAttribute s as MyNewlyRedefine dGroupAttribute

Be able to use my redefined flattened structure without getting
"There is no interface that accepts these parameters
(myapp.MyNewlyR edefinedGroupAt tribute, Nokia.TCSapi.tc sGroupAttribute sMask_t,
int16)"

Create(myNewlyR edefinedGroupAt tributes, groupAttributes Mask, cookie)

Is it possible to just edit the IL and reassemble or will I get that
"missingfieldex ception"?

Thanks in advance Mattias!

Aaron
"Mattias Sjögren" wrote:

Aaron,

>This struct has a member which is a struct
>which contains an array of another struct.

That's unfortunately not supported by the marshaler. See

http://dotnetinterop.com/faq/?q=StructWithStructArray

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Aaron]

> Be forewarned, I haven't tried this specifically.

Hehe, sounds fun, I'll give it a shot!
Thx for the response man.

[Aaron]

OLEView allowed me to view the types but not edit/rebuild. Any other
suggestions?

I tried editing the IL file, but once I change the field definitions for a
struct, I get a MissingFieldExc eption after reassembling/deploying/running my
app. I tried changing the valuetype myobject[] struct members to pointers
(native int) and thats when I get a *runtime* error of missingFieldExc eption
(although it does compile). Anyways, any other ideas?

"tcarvin" wrote:

Couldn't you just alter the typelib for your COM component? You can use a tool
like OLE View to extract the type lib from the COM component, which you could
then modify and rebuild. Be forewarned, I haven't tried this specifically.

Tom

"Aaron" <Aa***@discussi ons.microsoft.c om> wrote in message news:<35******* *************** ************@mi crosoft.com>...

In other words, how do I go about _flattening_ my structure when I don't have
the source code for the COM component to change the c++ source and do a
recompile. Can I do something with the IL or a switch to the TLBIMP.exe? Any
help appreciated!

"Aaron" wrote:

First of all, thanks for the response Mattias! I notice you consistently
help us problem ridden posters and let me just say we really appreciate the
time you take helping us.

Regarding my issue, I don't have the source code for the COM component so am
unable to change the type definitions for the Struct members. This dll does
not export these methods either, so, if I understand PInvoke correctly, I am
unable to use PInvoke since the method isn't exported. So, knowing what I
know now from the info contained in the link you referred to, if I were able
to flatten the struct members (get rid of array references, which I would
like to do anyways since I am always just passing in 1) this method would
complete S_OK. <- :s

So the question now is, is it possible to _redefine_ a structure which is
declared in the namespace of the COM component? So I would be able to call
'pseudo code
Structure MyNewlyRedefine dGroupAttribute
...
... ' redefine the array structure to be non-arrays
end structure
Dim myNewlyRedefine dGroupAttribute s as MyNewlyRedefine dGroupAttribute

Be able to use my redefined flattened structure without getting
"There is no interface that accepts these parameters
(myapp.MyNewlyR edefinedGroupAt tribute, Nokia.TCSapi.tc sGroupAttribute sMask_t,
int16)"

Create(myNewlyR edefinedGroupAt tributes, groupAttributes Mask, cookie)

Is it possible to just edit the IL and reassemble or will I get that
"missingfieldex ception"?

Thanks in advance Mattias!

Aaron
"Mattias Sjögren" wrote:

> Aaron,
>
> >This struct has a member which is a struct
> >which contains an array of another struct.
>
> That's unfortunately not supported by the marshaler. See
>
> http://dotnetinterop.com/faq/?q=StructWithStructArray
>
>
>
> Mattias
>
> --
> Mattias Sjögren [MVP] mattias @ mvps.org
> http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
> Please reply only to the newsgroup.
>

[tcarvin]

Sorry I wasn't clear. You can use OLE View to capture the IDL source (copy-n-
paste). You can then edit it, and then recompile it using MIDL. It is the
TypeLib that Visual Studio uses to map to the component's signitures. Of
course, you have to be sure to not actually break one of those signitures, just
"bend" it a little. Like flattening your array to let .NET call it. It doesn't
change the actual data layout in memory so the COM component will be none the
wiser.

I hope that helps,
Tom

"Aaron" <Aa***@discussi ons.microsoft.c om> wrote in message news:<72******* *************** ************@mi crosoft.com>...

OLEView allowed me to view the types but not edit/rebuild. Any other
suggestions?

I tried editing the IL file, but once I change the field definitions for a
struct, I get a MissingFieldExc eption after reassembling/deploying/running my
app. I tried changing the valuetype myobject[] struct members to pointers
(native int) and thats when I get a *runtime* error of missingFieldExc eption
(although it does compile). Anyways, any other ideas?

"tcarvin" wrote:

Couldn't you just alter the typelib for your COM component? You can use a tool
like OLE View to extract the type lib from the COM component, which you could
then modify and rebuild. Be forewarned, I haven't tried this specifically.

Tom

"Aaron" <Aa***@discussi ons.microsoft.c om> wrote in message news:<35******* *************** ************@mi crosoft.com>...

In other words, how do I go about _flattening_ my structure when I don't have
the source code for the COM component to change the c++ source and do a
recompile. Can I do something with the IL or a switch to the TLBIMP.exe? Any
help appreciated!

"Aaron" wrote:

> First of all, thanks for the response Mattias! I notice you consistently
> help us problem ridden posters and let me just say we really appreciate the
> time you take helping us.
>
> Regarding my issue, I don't have the source code for the COM component so am
> unable to change the type definitions for the Struct members. This dll does
> not export these methods either, so, if I understand PInvoke correctly, I am
> unable to use PInvoke since the method isn't exported. So, knowing what I
> know now from the info contained in the link you referred to, if I were able
> to flatten the struct members (get rid of array references, which I would
> like to do anyways since I am always just passing in 1) this method would
> complete S_OK. <- :s
>
> So the question now is, is it possible to _redefine_ a structure which is
> declared in the namespace of the COM component? So I would be able to call
> 'pseudo code
> Structure MyNewlyRedefine dGroupAttribute
> ...
> ... ' redefine the array structure to be non-arrays
> end structure
> Dim myNewlyRedefine dGroupAttribute s as MyNewlyRedefine dGroupAttribute
>
> Be able to use my redefined flattened structure without getting
> "There is no interface that accepts these parameters
> (myapp.MyNewlyR edefinedGroupAt tribute, Nokia.TCSapi.tc sGroupAttribute sMask_t,
> int16)"
>
> Create(myNewlyR edefinedGroupAt tributes, groupAttributes Mask, cookie)
>
> Is it possible to just edit the IL and reassemble or will I get that
> "missingfieldex ception"?
>
> Thanks in advance Mattias!
>
> Aaron
> "Mattias Sjögren" wrote:
>
> > Aaron,
> >
> > >This struct has a member which is a struct
> > >which contains an array of another struct.
> >
> > That's unfortunately not supported by the marshaler. See
> >
> > http://dotnetinterop.com/faq/?q=StructWithStructArray
> >
> >
> >
> > Mattias
> >
> > --
> > Mattias Sjögren [MVP] mattias @ mvps.org
> > http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
> > Please reply only to the newsgroup.
> >

[tcarvin]

Sorry I wasn't clear. You can use OLE View to capture the IDL source (copy-n-
paste). You can then edit it, and then recompile it using MIDL. It is the
TypeLib that Visual Studio uses to map to the component's signitures. Of
course, you have to be sure to not actually break one of those signitures, just
"bend" it a little. Like flattening your array to let .NET call it. It doesn't
change the actual data layout in memory so the COM component will be none the
wiser.

I hope that helps,
Tom

"Aaron" <Aa***@discussi ons.microsoft.c om> wrote in message news:<72******* *************** ************@mi crosoft.com>...

OLEView allowed me to view the types but not edit/rebuild. Any other
suggestions?

I tried editing the IL file, but once I change the field definitions for a
struct, I get a MissingFieldExc eption after reassembling/deploying/running my
app. I tried changing the valuetype myobject[] struct members to pointers
(native int) and thats when I get a *runtime* error of missingFieldExc eption
(although it does compile). Anyways, any other ideas?

"tcarvin" wrote:

Couldn't you just alter the typelib for your COM component? You can use a tool
like OLE View to extract the type lib from the COM component, which you could
then modify and rebuild. Be forewarned, I haven't tried this specifically.

Tom

"Aaron" <Aa***@discussi ons.microsoft.c om> wrote in message news:<35******* *************** ************@mi crosoft.com>...

In other words, how do I go about _flattening_ my structure when I don't have
the source code for the COM component to change the c++ source and do a
recompile. Can I do something with the IL or a switch to the TLBIMP.exe? Any
help appreciated!

"Aaron" wrote:

> First of all, thanks for the response Mattias! I notice you consistently
> help us problem ridden posters and let me just say we really appreciate the
> time you take helping us.
>
> Regarding my issue, I don't have the source code for the COM component so am
> unable to change the type definitions for the Struct members. This dll does
> not export these methods either, so, if I understand PInvoke correctly, I am
> unable to use PInvoke since the method isn't exported. So, knowing what I
> know now from the info contained in the link you referred to, if I were able
> to flatten the struct members (get rid of array references, which I would
> like to do anyways since I am always just passing in 1) this method would
> complete S_OK. <- :s
>
> So the question now is, is it possible to _redefine_ a structure which is
> declared in the namespace of the COM component? So I would be able to call
> 'pseudo code
> Structure MyNewlyRedefine dGroupAttribute
> ...
> ... ' redefine the array structure to be non-arrays
> end structure
> Dim myNewlyRedefine dGroupAttribute s as MyNewlyRedefine dGroupAttribute
>
> Be able to use my redefined flattened structure without getting
> "There is no interface that accepts these parameters
> (myapp.MyNewlyR edefinedGroupAt tribute, Nokia.TCSapi.tc sGroupAttribute sMask_t,
> int16)"
>
> Create(myNewlyR edefinedGroupAt tributes, groupAttributes Mask, cookie)
>
> Is it possible to just edit the IL and reassemble or will I get that
> "missingfieldex ception"?
>
> Thanks in advance Mattias!
>
> Aaron
> "Mattias Sjögren" wrote:
>
> > Aaron,
> >
> > >This struct has a member which is a struct
> > >which contains an array of another struct.
> >
> > That's unfortunately not supported by the marshaler. See
> >
> > http://dotnetinterop.com/faq/?q=StructWithStructArray
> >
> >
> >
> > Mattias
> >
> > --
> > Mattias Sjögren [MVP] mattias @ mvps.org
> > http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
> > Please reply only to the newsgroup.
> >