1. Write a class. It must extend System.EnterpriseServices.ServicedComponent. Declaratively mark up the class and its members with any required attributes.
2. Generate a strong name (key). All assemblies that run under Enterprise Services must be signed.
3. Add Assembly information. At a minimum you need to set the ApplicationName and AssemblyKeyFile attributes. The latter is what links the assembly with the key generated in the previous step.
4. Compile the assembly.
5. Deploy the assembly:
   • Place the assembly in the Global Assembly Cache. This is not required, but is definitely recommended.
   • Register the assembly with COM+. Here you have three options: a) Manual registration using the regsvcs.exe command line utility; b) Programmatic registration using the RegistrationHelper class in the System.EnterpriseServices namespace; c) Lazy registration (recommended only for development purposes).
6. Build and run the client.

The remainder of this article will walk you through each of these steps, explaining them in greater detail.

Building a transactional application
With the following steps you will build a serviced component an assembly that runs under Enterprise Services) that simulates a banking transaction. You will then build a small Windows Forms client application to consume the component.

To build and run this application you will need the final version of the Microsoft .NET Framework and administrative rights to the Northwind database included with the Microsoft Database Engine or Microsoft SQL Server. The steps assume you are using Visual Studio .NET. This IDE is not, however, required to build this application.

The server component simulates a balance of funds between two accounts. The transfer involves both a withdrawal and a deposit. To keep things simple, the transfer occurs within the same "bank," using the same database, and all of the business tier code is in a single class. As such, the transaction could have been handled entirely by SQL Server. In the real world, of course, this would normally not be the case.

Creating the database using Visual Studio .NET
You will need a new database for this example. Visual Studio .NET provides a convenient way to create databases using the new Server Explorer.

1. Start Visual Studio .NET.


2. Create a new Visual Basic .NET Windows Application project called "TransDemo".


3. Select the View | Server Explorer menu command (or press CTRL+ALT+S) to open the Server Explorer.


4. Expand Servers | SQL Servers | <Your computer name>.


5. Right-click the server instance to which you will add a new database and select New Database.


6. In the New Database Name field type BigBank.
7. Select Use Windows NT Integrated Security, and then click OK.
   
   
   Figure 1: Creating the database


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