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VB5's Enterprise Edition scales up with bundled client/server tools, Microsoft Transaction Server 1.0, and a developer version of SQL Server 6.5.
Three Flavors
VB5 comes in three editions: Learning, Professional, and Enterprise. The Learning Edition replaces VB4's Standard Edition, adding an interactive CD-ROM tutorial based on Microsoft's Mastering series. You can't create ActiveX controls with this version, but the freeware Control Creation Edition, which is posted on Microsoft's Web site, comes bundled in the box.
All four editions feature VB5's sleek
new IDE
, but only the Professional and Enterprise versions leverage the new extensibility model, which exposes virtually all the product's capabilities to programmatic control. This pays off immediately in a series of new Wizards and add-ins.
Active Creation
You can create ActiveX controls from scratch, by combining existing controls, or by extending the features of
other controls using subclassing. VB5 lets you work on multiple projects simultaneously to test and debug an ActiveX control project within a separate host project.
The new Forms Layout window lets you position your application's forms at design time, adjusting the look and feel at different resolutions. The Properties window adds a new Categorized view that groups properties by type. The Object Browser can now search one or all referenced libraries and then jump you directly to modules and procedures in your projects.
Active Intelligence
VB5's IntelliSense features take advantage of ActiveX's COM technology, which automatically exposes type information, including objects, properties, methods, and statements. The code window bristles with interactive tools: Quick Info displays context-sensitive syntax for statements and functions, List Members provides a drop-down list of properties and methods when you enter a control's name, and Complete Word fleshes out entity names as you t
ype.
Debugging is smarter, too. In break mode, when you position the cursor over a variable, a Data Tip pops up, displaying the value. You can run code at design time and in break mode from the Immediate window, drag a variable from the code window into the Watch window, and set breakpoints and current lines by clicking visual margin indicators.
VB5's language enhancements center on the new ActiveX-creation capabili-ties. You can raise events in your components and handle events raised by other applications or your own objects. The
Implements
statement supports polymorphism, allowing multiple classes to respond to the same interface.
Rolling your own ActiveX control is not a trivial endeavor, but the ActiveX Control Interface Wizard makes it easier by marrying properties, methods, and events for common controls with your own custom interface. The Property Page Wizard assembles a tabbed properties dialogue that your control's user accesses at design time by right-clicking on the cont
rol.
The Professional and Enterprise versions support the creation of
Active Documents
, a new VB project type that creates applications that can be run in Microsoft's Internet Explorer (see the sidebar "From Form to Active Document"). VB4's Setup Wizard has been enhanced to support ActiveX controls and Active Documents, packaging your components into compressed
CAB
files (short for Cabinet files) and generating sample Hypertext Markup Language (HTML) code that points at your control.
You can link to secondary
CAB
files, such as VB5's 700-KB run-time component and other data-access modules, or point at a central location on your intranet. When a browser user clicks on your control or jumps to an Active Document page, the ActiveX code is downloaded to the user's machine, verified for safety, decompressed, registered in the Windows registry, installed, and then activated.
True Compilation
With VB5's native-code compiler technology, deve
lopers now have the choice of compiling in VB's interpreted pseudocode format or directly in optimized native-code format.
Compiled code delivers up to 20 times the performance of pseudocode; this is particularly noticeable with compute-intensive operations common to three-tier distributed applications. To use the multithreading support, you must use the Unattended Execution option to build components that suppress all message boxes and dialog boxes, letting your program operate unattended on remote computers.
To the Enterprise
The Enterprise Edition tools move well beyond VB4's tentative steps into three-tier development. Microsoft Transaction Server shields VB developers from the complexities of distributed component architectures, handling server registration, process and thread management, resource management and synchronization, and component-based security.
The Visual Database Tools incorporate Microsoft Access's drag-and-drop user interface. The Database Designer fo
r SQL Server 6.5 directly attaches to your prototype database; you can interactively change SQL field data types and let the Database Designer rebuild your database under document description language (DDL) script control. The Query Designer allows you to construct SQL statements with visual and direct editing windows, updating in real-time on one screen.
VB5 provides an integrated Transact SQL Debugger that lets you step through stored procedure code as if it were application code. Other tools streamline data connections, save processing time with batch operations, and perform simulations to profile multitier application performance in different network topologies.
The Last Box
VB5 will prove to be as important to Microsoft's fortunes as it is for programmers'. The ActiveX and Active Documents technologies provide an automated migration path via the Web that can transparently replicate changes to Microsoft Office, Back Office, and Windows tools as you browse the Web. This versi
on may be the last copy of VB that you buy in a box.
Where to Find
Visual Basic 5.0....................Price unavailable at press time
Requires 486/66, Windows 95 or NT, a VGA or better monitor, and
CD-ROM. Memory and disk requirements vary with the three editions.
Microsoft Corp.
Redmond, WA
Phone: (206) 882-8080
Fax: (206) 936-7329
Internet:
http://www.microsoft.com/vbasic/
Circle 1087 on Inquiry Card.
The Basics of Web Development
