Role-specific COM+ Interview Questions & Answers:

1. How to make a NET component talk to a COM component?

To enable the communication between COM and .NET
components, the .NET Framework generates a COM Callable
Wrapper (CCW).

The CCW enables communication between the calling COM code
and the managed code. It also handles conversion between
the data types, as well as other messages between the COM
types and the .NET types.

2. What is CCW (COM Callable Wrapper)?

A proxy object generated by the common language runtime so
that existing COM applications can use managed classes,
including .NET Framework classes, transparently.

3. How does you handle this COM components developed in other programming languages in .NET?

by creating typelibraries & wrapper classes

4. How to register com+ services?

we acn register the Com+ services using the "regsvcs"
command

5. What is use of ContextUtil class?

ContextUtil is the preferred class to use for obtaining
COM+ context information.

6. What is the new three features of COM+ services, which are not there in COM (MTS)?

1) Automatic Transaction
2) Distributed Transactions
3) Object Pooling

7. Is the COM architecture same as .Net architecture? What is the difference between them?

com architecture needs registratation & classids where as .net
architecture does not need registration & classids

8. Explain what are wrapper Classes?

Wrapper classes are used to encapsulate values of primitive
types in objects, so that they can be passed around in the
same manner.

9. What are CCW and RCW?

Com Callable Wrapper
1)Create Assembly and compile with strong name.
2)Register Assembly using regasm <assembly name>
3)Register Assembly in GAC using gacutil /i <assembly name>
4)Use tlbexp <assemblyname.dll> to export Assembly as Type
Library for COM.

Runtime Callable Wrapper
1)Create Public Key Token file using sn.exe –k
<keyfilename.snk>
2)Use tlbimp <TypeLibFileName> /keyfile: <keyfilename.snk>
/out: <AssemblyName.dll>
3)Register Imported Assembly in GAC using gacutil /i
<AssemblyName.dll>

10. Explain Disadvantages of com components?

1. Does not supports implement-inheritence
2. Version compatibility.
3. Fully dependant on registry hence doesn't work on non-window platforms.,