Skip to Main Content
C# in a Nutshell, Second Edition
book

C# in a Nutshell, Second Edition

by Peter Drayton, Ben Albahari, Ted Neward
August 2003
Intermediate to advanced content levelIntermediate to advanced
928 pages
32h 1m
English
O'Reilly Media, Inc.
Content preview from C# in a Nutshell, Second Edition

Exposing COM Objects to C#

When you instantiate a COM object, you are actually working with a proxy known as the Runtime Callable Wrapper (RCW). The RCW is responsible for managing the lifetime requirements of the COM object and translating the methods called on it into the appropriate calls on the COM object. When the garbage collector finalizes the RCW, it releases all references to the object it was holding. For situations in which you need to release the COM object without waiting for the garbage collector to finalize the RCW, you can use the static ReleaseComObject method of the System.Runtime.InteropServices.Marshal type.

The following example demonstrates how to change your MSN Instant Messenger friendly name using C# via COM Interop:

// RenameMe.cs - compile with:
//   csc RenameMe.cs /r:Messenger.dll
// Run RenameMe.exe "new name" to change your name
//   as it is displayed to other users.
// Run TlbImp.exe "C:\Program Files\Messenger\msmsgs.exe"
//   to create Messenger.dll
using System;
using Messenger;
class MSNFun {
    static void Main(string[ ] args) {
        MsgrObject mo = new MsgrObject( );
        IMsgrService ims = mo.Services.PrimaryService;
        ims.FriendlyName = args[0];
    }
}

You can also work with COM objects using the reflection API. This is more cumbersome than using TlbImp.exe, but is handy in cases in which it’s impossible or inconvenient to run TlbImp.exe. To use COM through reflection, you have to get a Type from Type.GetTypeFromProgID( ) for each COM type you want to work with. ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

C# in a Nutshell

C# in a Nutshell

Ben Albahari, Ted Neward, Peter Drayton
C# 7.0 in a Nutshell

C# 7.0 in a Nutshell

Joseph Albahari, Ben Albahari
C# Cookbook, 2nd Edition

C# Cookbook, 2nd Edition

Jay Hilyard, Stephen Teilhet
C# Cookbook

C# Cookbook

Stephen Teilhet, Jay Hilyard

Publisher Resources

ISBN: 0596005261Catalog PageErrata