This appendix introduces some of the important new features in Visual Basic 5 not specific to Internet database development. You can become more familiar with the features mentioned here by reading other Sams books that concentrate on Visual Basic, such as Teach Yourself Visual Basic 4 in 21 Days or Visual Basic 5.0 Unleashed or the documentation that ships with Visual Basic. This appendix covers topics such as the redesigned development environment and the WinSock ActiveX control.
One of the most obvious enhancements to Visual Basic 5 is the new development
environment. Long-term plans for the Visual Basic 5 environment is to use the Developer
Studio environment used in other Microsoft development products, such as Visual J++
and Visual C++. Of course, you still can use the old familiar Visual Basic development
environment referred to as the SDI Development option, but take my advice: Use the
new interface shown in Figure A.1. It is much more functional.
FIGURE
A.1. The Visual Basic Developer Studio
environment.
Coding in Visual Basic 5 has been enhanced and made simpler with features such
as the Auto Statement Builder. This feature displays a drop-down box listing all
the valid properties and methods when you reference an object or ActiveX control
in the Code window. After you select the proper method or property (by pressing the
spacebar), the selected method or property name is placed in your code. The Auto
Quick Information feature feature provides you with the proper function and method
syntax as you code. When you create procedures and functions in forms and modules,
you now can assign a description to the procedure or function by using the Procedure
Attributes dialog boxes:Procedure Attributes dialog box shown in Figure A.2. Descriptions
that you add by using this dialog box are displayed when you view the module or form
with the Object Browser; this capability enables you to determine functionality without
reviewing the code and searching for comments.
FIGURE
A.2. The Procedure Attributes dialog box.
The Visual Basic 5 debugger has been improved in many ways. Breakpoint lines now
appear in red, and a stop sign icon appears in the left margin of the Code window
to make these lines easier to find. As you step through the code using the debugger,
you will notice that the current line of code that is about to be executed is shown
in yellow; a yellow-arrow icon appears in the left margin of the Code window to make
it easier for you to see what line of code you are on. The standard Debug window
has been replaced by a dockable immediate window, watches, and--my favorite--the
local window. The local window tracks the values for all the local variables in a
function or procedure without requiring you to type them in or add them. Forms and
ActiveX controls also appear in the local window. This window enables you to expand
the form or control and to view the current property settings. You now can add watch
variables by dragging the variable or object from the Code window to the Watch window.
Figure A.3 shows some of the many improved debugging features.
FIGURE
A.3.VB 5 Debugging Features dialog boxDebugging Features dialog boxdialog
boxes:Debugging Features.
Project enhancements have been added to Visual Basic 5, such as the capability to work with multiple projects in the same session. The Project dialog boxdialog boxes:ProjectProject dialog box also has been added to improve the project-creation process. This dialog box appears when you start Visual Basic 5 or a new project. You then can select from existing projects or create a new project. Your project choices follow:
Selecting a project type creates a new project of the selected type with the required
objects for the project. When you select Standard Exe, for example, the project created
contains a single form. If you select ActiveX Control, the new project contains a
single UserControl object. You can choose Application Wizard to generate
a fully functional application that you easily can modify or enhance. Figure A.4
shows the introductory Application Wizard dialog box. (You'll take a look at other
Visual Basic wizards in the next section, "More Wizards.")
FIGURE
A.4.The first Application Wizard dialog box.
Many new file types have been added to Visual Basic 5. Table A.1 lists these file
types and their new extensions.)
Table A.1. Visual Basic 5 File Types.
| File Type | Extension |
| Active Designer Binary File | .dsx |
| Active Designer Cache | .dca |
| Active Designer File | .dsr |
| ActiveX Control | .ocx |
| ActiveX Document Binary Form | .dox |
| ActiveX Document Form | .dob |
| Binary Property Page File | .pgx |
| Class | .cls |
| Control Licensing File | .vbl |
| DLL | .dll |
| Executable | .exe |
| Form | .frm |
| Module | .bas |
| Property Page File | .pag |
| Setup Wizard Dependency File | .dep |
| User Control Binary File | .ctx |
| User Control File | .ctl |
| VB Group Project File | .vbg |
| VB Project Workspace File | .vbw |
| VB Setup Wizard Template File | .swt |
Visual Basic 5 is packed with many wizards to make application development easier
and faster. Table A.2 lists the wizards offered in Visual Basic 5.
Table A.2. Visual Basic 5 Wizards.
| Wizard | Function |
| ActiveX Control | Helps you develop ActiveX controls. |
| Interface Wizard | |
| ActiveX Control Interface Wizard | |
| ActiveX Document | Migrates existing Visual Basic applications |
| Migration Wizard | into ActiveX document objects |
| ActiveX Document Migration Wizard. | |
| Application Wizard | Generates full-blown applications |
| Application Wizard. | |
| Class Wizard | Provides a graphical tool to help you design and maintain classes |
| Class Wizard. | |
| Data Form Wizard | Generates Visual Basic forms that use data-bound controls to add, update, delete, and query information from a database table |
| Data Form Wizard. | |
| Property Page Wizard | Helps developers construct property pages for user-created ActiveX controls |
| Property Page Wizard. | |
| Setup Wizard | Builds installation routines for user applications |
| Setup Wizard. | |
| Wizard Manager | Helps application developers build wizards |
| Visual Basic 5.0:Wizards | |
| Wizards:Visual Basic 5.0 | |
| Wizard Manager. |
Most wizards are delivered as Visual Basic add-ins--applications that integrate into the Visual Basic design environment using the Add-In Manager. After you register a Visual Basic add-in, you can choose it from the Add-Ins menu in the main Visual Basic Development window.
To register a Visual Basic add-in, follow these steps:
FIGURE A.5.The Add-In Manager dialog box
The add-ins now are registered and will appear on the Add-Ins menu when you access it.
One of the most requested features for Visual Basic has been a native code compiler. Previous versions of Visual Basic compiled code into p-code executables. P-code is not compiled to machine instructions (native) and therefore cannot be executed directly. Instead, p-code executables use an interpreter to convert the p-code into machine instructions. Applications created with p-code don't execute as fast as native-compiled applications. Visual Basic 3 and 4 were criticized for not being able to generate native compiled code like some of their competitors. Visual Basic 5 finally delivers a native code-compiler option. You can generate native code executables for faster execution. You still have the option to create p-code executables, however.
Many of the Visual Basic controls used in previous versions of Visual Basic have
been enhanced in Version 5. Table A.3 lists the new controls offered in the Visual
Basic 5 toolbox.
Table A.3. Visual Basic 5 Controls.
| Control | Function |
| Animation | Displays AVI clips. |
| Animation control | |
| ActiveX:controls:Animation | |
| Chart | Offers a pivot capability (still provides backward compatibility with the old Chart control). |
| Chart control | |
| ActiveX:controls:Chart | |
| Internet Transfer | Enables you to get and retrieve files from FTP and HTTP servers. |
| Internet Transfer control | |
| ActiveX:controls:Internet Transfer | |
| MsFlexGrid | Provides enhanced grid control to give you more individual cell control and data-binding options. |
| MsFlexGrid control | |
| ActiveX:controls:MsFlexGrid | |
| Visual Basic 5.0:ActiveX controls | |
| ActiveX:controls | |
| Up/Down | Enables you to add increment and decrement features to other ActiveX controls by using the up- and down-arrow buttons. |
| Up/Down control | |
| ActiveX:controls:Up/Down | |
| WebBrowser | Adds WWW browser capabilities. |
| WebBrowser control | |
| ActiveX:controls:WebBrowser | |
| WinSock | Adds TCP/IP and UDP (User Datagram Protocol) socket capabilities using an ActiveX control. |
| Visual Basic 5.0:ActiveX controls | |
| ActiveX:controls | |
| WinSock control | |
| ActiveX:controls:WinSock |
Many language features and changes have been added to Visual Basic 5. Several important features--such as interfaces, friend functions, and default properties--already have been discussed in Chapters 8, "Using Classes and Objects in Visual Basic 5," and 16, "Creating ActiveX Controls for the Web with VB 5." This section outlines some of the other language enhancements in Visual Basic 5.
If you spent any time using previous versions of Visual Basic with the Windows API, you probably noticed that you can't use a Windows API that requires the address of a function. This problem occurred because you could not pass the address of a Visual Basic function or procedure to a Windows API. Visual Basic 5 offers a new keyword called AddressOf that returns the address of the Visual Basic function. The address of the function you want must reside in a .BAS module. When using the AddressOf keyword, you cannot intercept Windows messages in Visual Basic (this is called subclassing).
Optional arguments in procedures and functions now can be of any data type (Visual Basic 4 allowed only variant-type optional arguments). The property procedures Let and Get also can have optional arguments. Class modules now can contain a single property that can be designated as the default property.
Several keywords, such as Events and RaiseEvents, have been added to enable you to create and fire your own events. The WithEvents keyword enables your application to handle and respond to events that fire in an ActiveX component.
Visual Basic 5 will ship with the following editions:
The Custom Control Edition is for developers that just want to develop ActiveX controls. The Standard Edition includes the basic functionality of Visual Basic but does not include database features. The Professional Edition includes all the standard database features like DAO. The Enterprise Edition of Visual Basic 5 offers several new features that are worth examining, for instance a developer version of Microsoft SQL Server 6.5.
If you work with Visual Basic and SQL Server, you will want to learn how to use the SQL Server stored procedure debuggerSQL SspdVisual Basic 5.0:SQL Sspd. SQL Server does not come with a debugger, and trying to debug a complicated SQL Server stored procedure always has been a problem. The SQL Server debugger integrates directly into the Visual Basic development environment and enables you to go through a stored procedure step by step to view stored procedure variables. The Enterprise Edition also includes Visual Source Safe to manage code revisions and multiple programmers working on the same project. A developer version of the Microsoft Transaction Server is included as well as native support for RISC platforms. One of the most useful features is a set of tools referred to as the Visual Database tools that allows you to create graphical queries and manage SQL Server and Oracle database schema from the Visual Basic developer environment.
You probably have heard about three-tier applications. The classic three-tier
model consists of data services, business services (rules), and client services.
The goal of the three-tier architecture is to distribute processing and reduce the
amount of software distribution and headaches caused when a business rule or new
data service is added or changed. Versions prior to Visual Basic 4 were used in two-tier
client/server applications; Visual Basic 4 added remote automation, which made three-tier
applications possible. In Visual Basic 4, you could create a client front-end application
to provide the client services (user request), an OLE Automation server (ActiveX
component) using remote automation as business services, and SQL Server as data services.
Visual Basic 5 simplifies three-tier applications by providing distributed components
that use COM with Windows 95 and Windows NT 4. Remote automation still is available
for other Windows platforms such as Windows 3.11 and Windows NT 3.51. Figure A.6
shows the Remote Automation Connection Manager.
FIGURE
A.6.The Remote Automation Connection Manager dialog box.
The ActiveX Designers are features new to Visual Basic 5. These designers help automate tasks that normally require a great deal of code. An ActiveX Designer is not a wizard; instead, it is similar to the standard Visual Basic Form Designer. When you add an ActiveX Designer to a project, the ActiveX Designer creates classes in your project. You then can use the classes created by the ActiveX Designer to create objects and invoke the methods of the object. To aid in code modification and speed development, the ActiveX Designer may offer a Design window to provide a graphical interface to the classes and code. You also can add your own properties and methods to the classes. To see an example using the UserConnection ActiveX Designer, refer to Chapter 9, "Visual Basic 5 Data Access Features."
