Hi Praveen,
The QC API which you are using in the C# code is COM based. that is why its header showing like "System.__ComObject".
if you expand the System.__ComObject then you wil get all the lists which is you are trying to fetch.
Please debug your code and Quick watch the System_ComObject, you will get everything depend on what QC API Class/interface you are fetching.
Regards,
Ramesh