Professional Visual Basic 6 D Istributed Objects

by Rockford Lhotka

Visual Basic is the leading Windows development tool with 3-4 million licenses sold. Many VB developers face the challenge of building scalable applications using distributed COM objects in Visual... This description may be from another edition of this product.

• Format: Paperback
• Language: English
• ISBN: 1861002076
• ISBN13: 9781861002075
• Release Date: May 1999
• Publisher: Wrox Press
• Length: 452 Pages
• Weight: 1.85 lbs.
• Dimensions: 1.1" x 7.3" x 9.3"

Customer Reviews

Simply Outstanding

The concepts and ideas presented in this book (as well as the Business Objects book) should be in the "toolbox" of every serious Visual Basic developer. The examples are concise and the concepts are easy to read and understand. I recently developed an n-tier e-commerce web application using the author's concepts for the middle tier. This was my first full-scale, enterprise-level effort, and I found the architecture easy to implement and the performance and scalability to be superb.Incidentally, the support from the author and publisher are excellent as well. When I had a question about the subject matter in the book, I e-mailed the author. I received a personal reply from Mr. Lhotka, with a detailed answer to my question, in just a couple of days.

Amazing. This book is a must for every serious developer

I read a lot of books in VB but THIS one is necessary for all professional developer. It's an expert book, so don't search for a lot of user interface code in it. It's all about engine under the hood. A MUST. I don't consider buying this book if it's your first start in VB. Try Beginning Object and Businness Object before this one.

Great follow-up to VB6 Business Objects

In a nutshell, if you just read and liked Visual Basic 6 Business Objects, get a hold of this book.Basically, this book is following Lhotka's architecture while adding new features to it's implementation. Features such as State Rollback, Load Balancing, and obviously, more objects usage on a distributed environment.You will also find some good usage of MSMQ and web-oriented objects.The only thing still missing is to see where the authors would fit XML into all this.

The best book about distributed apps with VB and COM/MTS

Lhotka goes straight to the important matter about this topic: solid arquitecture, UI and data centered business objects, and passing object state across networks. He does not waste time with no-sense XML/CSS, Interdev and other useless "fashionable" stuff. He takes care of the real critical issues when developing distributed apps. I have been programming distributed apps for the last 3 years using several techniques & technologies (DCOM, MTS, TCP-IP, LU62, etc) and I really appreciate this book; it's full of substance. I use a very different approach than the one proposed by Lhotka (because I use direct Winsock connections with a custom AppServer), but I found this book very usefull to compare against my particular framework and to extract some nice ideas. If I were to program with DCOM/MTS/MSMQ, I would use Lhotka's framework and this book would be a definitive guide. It's full of very intelligent and practical concepts. Don't waste your money & time in other books about this topic. This is the one you need.

Must have follow up to Visual Basic 6 Business Objects

This book picks up where the author left off in his other book (Visual Basic 6 Business Objects). As a matter of fact, the framework from his other book falls apart when you try to work with more than 2 levels of parent-child relationships (i.e. Parent-Child-GrandChild...)The book deals with this problem specifically in Chapters 3 and 4. Lhotka modifies the framework to handle state stacking in Ch. 3. This modification allows n-level rollback for grandchild objects. Chapter 4 covers passing object state for n-level relationships. The passing object state chapter is critical because it shows you how to pack up all state information for an n-level relationship and send it as one string (byte array) to the parent persist object (which should be running in MTS). It explains how the parent persist object unpacks the string, saves its state, and then saves the state of every child (where every child saves it children, etc.). This allows the entire relationship tree to be saved within one MTS transaction. This was impossible to do with the old book with object relationships that have 3 or more levels.The chapter on MSMQ is very good. It is not the definitive reference for MSMQ programming, but it provides a very good method of enabling asynchronous processing within the current CSLA framework. He adds a Proxy-Server layer between the object code and the persist code, and the objects in this layer are capable of storing the object state for a parent (and its children, grandchildren, etc.), and setting themselves as the body of an MSMQ message. He also shows you a VB reader application that can read the queue and instantiate the proxy objects which then automatically perform the persist functions. The author does note that the reader app is just a demo and a true enterprise solution would be to develop an NT Service written in C/C++.However, a book can only go so far, and you must always add additional functionality before the framework can truly be used in an enterprise. One simple example involves MSMQ: When the business object fires off a proxy server object to persist or load data, it does not know if the proxy server is performing the function synchronously or asynchronously. I had to add functionality to provide the business object with this information and allow it to act accordingly.There are also some minor bugs in the code relating to state stacking that I had to fix. Overall though, the code is solid and the framework functions as promised. If you are using the CSLA framework from his other book, then you MUST get this book as well.