Watin + HttpWatch application issue after Windows Upgrade?

Question

We have an application using Watin and HttpWatch, to check for some production sites. We check response time of our applications at regular intervals and we use this application for that.

We open an IE instance and after setting some configs attach this instance with HttpWatch plugin. The application is working perfectly fine in Windows Server 2003.

But, we get the following error when we execute this application in Windows Server 2008.

Unable to cast COM object of type 'HttpWatch.ControllerClass' to interface type 'HttpWatch.IController'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{21828BF3-DA77-4FC1-968E-FC7A46AEC19A}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).

We have tried many things but unable to solve this issue. Also, we have put the latest DLLs for Interop.HttpWatch.dll and Interop.SHDocVw.dll for the required Windows Server 2008 version, as we got to know about it from a link.

Answer 1

Check if this is error due to 2003 -> 2008 transition or 32bit -> 64 bit.

I have similar errors with COM - and have to change compilation to 32 bit in some cases.

Answer 2

I finally fixed this issue.

The problem that was occurring as follows:

The project was built for Target Version -- Any CPU

The project made use of InternetExplorer Class of Watin, and IE for our machine is of target version x86, while my machine is x64. (Windows Server 2008 R2)

So when the application was trying to attach the x64 specific worker process to x86 IE instance, it was giving the above error.

I rebuilt the project for x86 platform, and now the application is working perfectly fine.

In case you have the same issue, try it doing this way. Do let me know if it helps!

Regards,

Varun Shringarpure