Problem calling a COM object within my webservice - please help....

[Michael]

Hi,

If anyone can help me identify the problem here I would appreciate it!
Here
are the details:

I created a Windows based .NET application that has a reference to a
COM object. The COM object was instainted successfully and all the
calls to this COM object worked fine.

I moved the classes that referenced the COM object into a WebService
and made a reference to the COM object, esstially the exact same code.
When the WebService instanitates the COM object within a try block it
seems ok but as soon as I attempt to call a method on the COM object
it raises an
NullReferenceException. Here are some of the details in the exception:

_COMPlusExceptionCode -532459699
_HResult -2147467261
_message "Object reference not set to an instance of an object."
_xcode -1073741819
_xptrs 11989016
HResult -2147467261

Here are things that I have tried:
- using the tlbimp utility to create a .NET assembly and referencing
the wrapper assembly
- I gave administrator privelegdes to the aspnet_wp user
- removed the IIS anynonyous flag and connect with web.config set to
impersonate
- added the following line before the COM is created:
Thread.CurrentThread.ApartmentState = ApartmentState.STA;
- moved and reregistered the COM's dll in the same bin directory as
the webservice itself.

Thanks in advance for your help.
Mike

 

[Michael Pearson]

The error you have seems to indicate that you didn't instantiate your COM
object yet.

Do you have something like this for your object?

oMyObject = new MyComObject.ClassName

Can you post some code so we can see what's going on in that code?

Michael

 

[Michael]

Thanks for responding Michael,

Here is the code snippet that I am using to instaintate the com
object:

try
{
Thread.CurrentThread.ApartmentState = ApartmentState.STA;
pbcodeinterfaceClass pbInterfaceCOM = new pbcodeinterfaceClass();
String directoryData;
String lib = "somevalue";
directoryData = pbInterfaceCOM.of_exportlibrarydirectory(lib,(Int16)1);
if (directoryData != String.Empty)
{
...more code
catch (Exception ex)
{
ex = ex;
return null;
}

The code only blow's up when I call a method
(of_ExportLibraryDirectory) of my COM object (pbInterfaceCOM). Again,
this code works perfect when run within a windows application.

Thanks!
Mike