Click here to close now.

Welcome!

.NET Authors: Aria Blog, Pat Romanski, Elizabeth White, Hovhannes Avoyan, Sanjeev Sharma

Related Topics: .NET

.NET: Article

Converting VB6 to VB.NET, Part I

A Look at Your Options and When to Use Them

If you're one of the many who have VB6 code, you have three basic options: stay with VB6, convert to .NET, or rewrite from scratch. In this article, we will look at converting VB6 code to VB.NET and C#. I'll discuss when it makes sense to convert versus staying with VB6 or rewriting from scratch. I will cover what converts well and what does not, different ways to do the conversion, how to get code ready to convert, and handling issues after the conversion.

Executive Overview
First, let's get an executive-level overview of where VB6 and VB.NET are at in their life cycles. Note that when I mention VB.NET in this article, I mean all three versions (2002, 2003, 2005). When I talk about a specific version, I will specify the version (such as VB.NET 2002). With the advances in VB.NET 2003, as well as its compatibility with VB.NET 2002, there is little reason to migrate to, or stay with, VB.NET 2002. VB.NET 2005 is still an unstable beta, so the focus here will be on converting to VB.NET 2003.

For those of you who wish to stay with VB6, the key fact is that VB6 developer licenses are perpetual, so developers who have licenses can continue to develop in VB6 for as long as they wish. However, VB6 was released in January 1999 and is approaching six years of age. As a result, it is near the end of its life (VB 1.0 was originally released in 1990). VB6 no longer exists as a stand-alone product - mainstream support ends in about six months - and all support will end three years after that. Currently, to get a new VB6 license, you must either buy VB.NET and then request a VB6 downgrade disk (for about $20), or get an MSDN subscription and download it from the archives. However, I wouldn't be surprised to see these dates extended.

VB6 can be a viable option for small- to medium-sized programs with limited lifespans, for several years to come. But for large, long-term projects that will need to be maintained for a number of years, VB6 is rapidly becoming a non-option.

VB.NET was in widespread beta, with some commercial applications shipping in 2001. Release 1.0 came in 2002 and version 1.1 showed up in 2003. VB.NET is clearly ready for primetime. As a bonus, Mainsoft Corp., Mono, and Portable.NET are preparing to take VB.NET code cross-platform.

VB.NET can be cheap; many VB6 developers are MSDN members and already have access to VB.NET. The stand-alone VB.NET product is about $110, and adventuresome folk can download a free copy of VB.NET 2005 that contains the upgrade wizard at lab.msdn.microsoft.com/vs2005/get/default.aspx. A DVD (or CD) of the VS2005 Enterprise version beta can be ordered for a shipping and handling fee from the same Web page. Serious developers and corporations will typically have one of the more expensive MSDN subscriptions and access to all of this and more.

Options
If you have VB6 code, your main choices are to stay with VB6, convert the code to VB.NET or C#, or rewrite the code from scratch in VB.NET, C#, or Java. If you plan to rewrite in Java, you are probably reading the wrong article (and probably the wrong magazine; may I suggest our fine sister publication JDJ).

Whether or not to convert a program is always a case-by-case decision, driven by several competing factors such as the quality of the original code, cost, programmer availability, customer base, etc. On one hand, the only clear case where not going through at least a trial conversion would make sense is if the product is at the end of its life, with only bug fixes being implemented, and no plans for future versions. On the other hand, few large VB6 programs will convert to VB.NET without some significant rewriting. In almost all cases, I think going through at least a quick "probe" conversion is a good exercise for almost all projects - even if the converted code is not used, some valuable lessons will be learned.

Although the focus of this article will be on VB6 to VB.NET conversions, those of you moving to C# or looking at a complete VB.NET rewrite can still benefit from a conversion to VB.NET. For those of you looking at moving to C#, there are several tools (we will take a quick look at a couple of them later) that convert VB.NET to C# (and back), so it makes sense to convert to VB.NET as a step on the way to C#. If you're planning to do a complete rewrite to either VB.NET or C#, you can use the VB.NET conversion wizard to get a head start. In most programs, there are blocks of code that implement algorithms or business logic. These blocks of converted code can be pasted into a new project, speeding development for those choosing to do a complete rewrite.

Also consider that there are different levels and methods of conversion. If you have an ActiveX control written in VB6, a true conversion would be to rewrite it as a WinForm control in VB.NET. A better option might be to wrap the control in a .NET wrapper and use it from .NET while converting and testing. Shipping a VB6 ActiveX control with a .NET application can complicate the install because the VB runtime and associated files must also be installed. This is the same installation that is required if the control is installed with a VB6 application, but it is obviously more complex than the simple XCopy install of pure .NET applications.

Another way in which this ActiveX wrapper trick can be used is on forms that do not convert well, regardless of the reason. If the form can be moved to a separate project that was created as an ActiveX control project, the resulting ActiveX control can be added to a replacement form in VB6 or to a VB.NET project. Any form that can be separated from the rest of the program in this manner can be converted to an ActiveX control and used from .NET using .NET's built-in interop capabilities. In addition, we will see that most simple DLLs can be easily used directly from .NET.

In converting from VB6 to VB.NET 2003, three areas will be looked at: general VB6 code, ADO database code, and ASP Web page code. In this article, I concentrate on using the upgrade wizard to convert general VB code to VB.NET. In the future articles, I will finish general conversion issues, covering ADO, ASP, C#, and VB.NET 2005.

Before We Even Start
Remove dead code; you cannot have trouble with code you do not convert. Remove variables that are never used and subroutines that are never called. I converted one application that was large enough to have a number of associated programs, such as configuration programs, format converters, upgrade tools, and some ActiveX controls. Most of these utilities shared header files (WIN32 API declare statements and user type definitions) with the main application, but most of these programs only used a few of the functions in the headers. Other applications did not use anything in some of the headers. By removing the unused files and functions from the project, I was able to convert all the utilities much quicker. This allowed some functionality to be shown quickly, and provided the experience needed to tackle the main application.

More Stories By Dennis Hayes

Dennis Hayes is a programmer at Georgia Tech in Atlanta Georgia where he writes software for the Adult Cognition Lab in the Psychology Department. He has been involved with the Mono project for over six years, and has been writing the Monkey Business column for over five years.

Comments (2)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
Roberto Medrano, Executive Vice President at SOA Software, had reached 30,000 page views on his home page - http://RobertoMedrano.SYS-CON.com/ - on the SYS-CON family of online magazines, which includes Cloud Computing Journal, Internet of Things Journal, Big Data Journal, and SOA World Magazine. He is a recognized executive in the information technology fields of SOA, internet security, governance, and compliance. He has extensive experience with both start-ups and large companies, having been involved at the beginning of four IT industries: EDA, Open Systems, Computer Security and now SOA.
The industrial software market has treated data with the mentality of “collect everything now, worry about how to use it later.” We now find ourselves buried in data, with the pervasive connectivity of the (Industrial) Internet of Things only piling on more numbers. There’s too much data and not enough information. In his session at @ThingsExpo, Bob Gates, Global Marketing Director, GE’s Intelligent Platforms business, to discuss how realizing the power of IoT, software developers are now focused on understanding how industrial data can create intelligence for industrial operations. Imagine ...
Operational Hadoop and the Lambda Architecture for Streaming Data Apache Hadoop is emerging as a distributed platform for handling large and fast incoming streams of data. Predictive maintenance, supply chain optimization, and Internet-of-Things analysis are examples where Hadoop provides the scalable storage, processing, and analytics platform to gain meaningful insights from granular data that is typically only valuable from a large-scale, aggregate view. One architecture useful for capturing and analyzing streaming data is the Lambda Architecture, representing a model of how to analyze rea...
SYS-CON Events announced today that Vitria Technology, Inc. will exhibit at SYS-CON’s @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Vitria will showcase the company’s new IoT Analytics Platform through live demonstrations at booth #330. Vitria’s IoT Analytics Platform, fully integrated and powered by an operational intelligence engine, enables customers to rapidly build and operationalize advanced analytics to deliver timely business outcomes for use cases across the industrial, enterprise, and consumer segments.
The explosion of connected devices / sensors is creating an ever-expanding set of new and valuable data. In parallel the emerging capability of Big Data technologies to store, access, analyze, and react to this data is producing changes in business models under the umbrella of the Internet of Things (IoT). In particular within the Insurance industry, IoT appears positioned to enable deep changes by altering relationships between insurers, distributors, and the insured. In his session at @ThingsExpo, Michael Sick, a Senior Manager and Big Data Architect within Ernst and Young's Financial Servi...
SYS-CON Events announced today that Open Data Centers (ODC), a carrier-neutral colocation provider, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place June 9-11, 2015, at the Javits Center in New York City, NY. Open Data Centers is a carrier-neutral data center operator in New Jersey and New York City offering alternative connectivity options for carriers, service providers and enterprise customers.
The explosion of connected devices / sensors is creating an ever-expanding set of new and valuable data. In parallel the emerging capability of Big Data technologies to store, access, analyze, and react to this data is producing changes in business models under the umbrella of the Internet of Things (IoT). In particular within the Insurance industry, IoT appears positioned to enable deep changes by altering relationships between insurers, distributors, and the insured. In his session at @ThingsExpo, Michael Sick, a Senior Manager and Big Data Architect within Ernst and Young's Financial Servi...
PubNub on Monday has announced that it is partnering with IBM to bring its sophisticated real-time data streaming and messaging capabilities to Bluemix, IBM’s cloud development platform. “Today’s app and connected devices require an always-on connection, but building a secure, scalable solution from the ground up is time consuming, resource intensive, and error-prone,” said Todd Greene, CEO of PubNub. “PubNub enables web, mobile and IoT developers building apps on IBM Bluemix to quickly add scalable realtime functionality with minimal effort and cost.”
Sensor-enabled things are becoming more commonplace, precursors to a larger and more complex framework that most consider the ultimate promise of the IoT: things connecting, interacting, sharing, storing, and over time perhaps learning and predicting based on habits, behaviors, location, preferences, purchases and more. In his session at @ThingsExpo, Tom Wesselman, Director of Communications Ecosystem Architecture at Plantronics, will examine the still nascent IoT as it is coalescing, including what it is today, what it might ultimately be, the role of wearable tech, and technology gaps stil...
In the consumer IoT, everything is new, and the IT world of bits and bytes holds sway. But industrial and commercial realms encompass operational technology (OT) that has been around for 25 or 50 years. This grittier, pre-IP, more hands-on world has much to gain from Industrial IoT (IIoT) applications and principles. But adding sensors and wireless connectivity won’t work in environments that demand unwavering reliability and performance. In his session at @ThingsExpo, Ron Sege, CEO of Echelon, will discuss how as enterprise IT embraces other IoT-related technology trends, enterprises with i...
When it comes to the Internet of Things, hooking up will get you only so far. If you want customers to commit, you need to go beyond simply connecting products. You need to use the devices themselves to transform how you engage with every customer and how you manage the entire product lifecycle. In his session at @ThingsExpo, Sean Lorenz, Technical Product Manager for Xively at LogMeIn, will show how “product relationship management” can help you leverage your connected devices and the data they generate about customer usage and product performance to deliver extremely compelling and reliabl...
The Internet of Things (IoT) is causing data centers to become radically decentralized and atomized within a new paradigm known as “fog computing.” To support IoT applications, such as connected cars and smart grids, data centers' core functions will be decentralized out to the network's edges and endpoints (aka “fogs”). As this trend takes hold, Big Data analytics platforms will focus on high-volume log analysis (aka “logs”) and rely heavily on cognitive-computing algorithms (aka “cogs”) to make sense of it all.
With several hundred implementations of IoT-enabled solutions in the past 12 months alone, this session will focus on experience over the art of the possible. Many can only imagine the most advanced telematics platform ever deployed, supporting millions of customers, producing tens of thousands events or GBs per trip, and hundreds of TBs per month. With the ability to support a billion sensor events per second, over 30PB of warm data for analytics, and hundreds of PBs for an data analytics archive, in his session at @ThingsExpo, Jim Kaskade, Vice President and General Manager, Big Data & Ana...
One of the biggest impacts of the Internet of Things is and will continue to be on data; specifically data volume, management and usage. Companies are scrambling to adapt to this new and unpredictable data reality with legacy infrastructure that cannot handle the speed and volume of data. In his session at @ThingsExpo, Don DeLoach, CEO and president of Infobright, will discuss how companies need to rethink their data infrastructure to participate in the IoT, including: Data storage: Understanding the kinds of data: structured, unstructured, big/small? Analytics: What kinds and how responsiv...
Since 2008 and for the first time in history, more than half of humans live in urban areas, urging cities to become “smart.” Today, cities can leverage the wide availability of smartphones combined with new technologies such as Beacons or NFC to connect their urban furniture and environment to create citizen-first services that improve transportation, way-finding and information delivery. In her session at @ThingsExpo, Laetitia Gazel-Anthoine, CEO of Connecthings, will focus on successful use cases.
Sensor-enabled things are becoming more commonplace, precursors to a larger and more complex framework that most consider the ultimate promise of the IoT: things connecting, interacting, sharing, storing, and over time perhaps learning and predicting based on habits, behaviors, location, preferences, purchases and more. In his session at @ThingsExpo, Tom Wesselman, Director of Communications Ecosystem Architecture at Plantronics, will examine the still nascent IoT as it is coalescing, including what it is today, what it might ultimately be, the role of wearable tech, and technology gaps stil...
The true value of the Internet of Things (IoT) lies not just in the data, but through the services that protect the data, perform the analysis and present findings in a usable way. With many IoT elements rooted in traditional IT components, Big Data and IoT isn’t just a play for enterprise. In fact, the IoT presents SMBs with the prospect of launching entirely new activities and exploring innovative areas. CompTIA research identifies several areas where IoT is expected to have the greatest impact.
Wearable devices have come of age. The primary applications of wearables so far have been "the Quantified Self" or the tracking of one's fitness and health status. We propose the evolution of wearables into social and emotional communication devices. Our BE(tm) sensor uses light to visualize the skin conductance response. Our sensors are very inexpensive and can be massively distributed to audiences or groups of any size, in order to gauge reactions to performances, video, or any kind of presentation. In her session at @ThingsExpo, Jocelyn Scheirer, CEO & Founder of Bionolux, will discuss ho...
SYS-CON Events announced today that GENBAND, a leading developer of real time communications software solutions, has been named “Silver Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. The GENBAND team will be on hand to demonstrate their newest product, Kandy. Kandy is a communications Platform-as-a-Service (PaaS) that enables companies to seamlessly integrate more human communications into their Web and mobile applications - creating more engaging experiences for their customers and boosting collaboration and productiv...
From telemedicine to smart cars, digital homes and industrial monitoring, the explosive growth of IoT has created exciting new business opportunities for real time calls and messaging. In his session at @ThingsExpo, Ivelin Ivanov, CEO and Co-Founder of Telestax, shared some of the new revenue sources that IoT created for Restcomm – the open source telephony platform from Telestax. Ivelin Ivanov is a technology entrepreneur who founded Mobicents, an Open Source VoIP Platform, to help create, deploy, and manage applications integrating voice, video and data. He is the co-founder of TeleStax, a...