COM+ Programming with Visual Basic

Services Overview

Now that you know how to create a COM+ application, add your components to it, and deploy it, you may be wondering about the advantage of having a COM+ application in the first place. The advantage is that adding components to your application enables you to use a number of COM+ services. If you examine the properties of a component in the COM+ Services Administration program (right-click on the component and choose Properties), you will notice that there are a number of services, which are available at different levels: the application, component, interface, and method levels of a COM+ object. The following list briefly describes each service and indicates whether it is available to library applications—if the item does not read “server applications only,” the service is available for both library applications and server applications:

Process-level security (server applications only)

Helps you set up DCOM security. DCOM security affects how a client gains access to the application. Without COM+, you would have to configure DCOM security manually using dcomcnfg.exe. You will learn more about this feature in Chapter 10. (See the dialog box on the left in Figure 7-14.)

Figure 7-14. Application Security Properties

Component-level security

Enables you to restrict or grant access to a component’s method by assigning access rights either at the component, interface, or ...