Let's create an array named students to store the number of students in each grade in a grammar school. The indexes of the elements range from 0 through 6. Using this array is simpler than declaring seven variables.
Your code interacts with an application programming interface (API) that either requires you to pass a zero-length array to one or more procedures or returns a zero-length array from one or more procedures.
This article shows how you'll use Visual Studio to create a simple Visual Basic application, a console app. In this app, you ask the user for their name, and then display it back with the current time. You'll also explore some features of the Visual Studio integrated development environment (IDE), including source control in Git. Visual Basic is a type-safe programming language that's designed to be easy to learn. A console app takes input and displays output in a command-line window, also known as a console.
The command vbc invokes the Visual Basic .NETcommand-line compiler, which ships with the .NET Framework SDK, andinstructs it to compile the file named in the command-line argument.Compiling Hello.vb generates the fileHello.exe. After compiling, typeHello at the command line to run your program.Figure 1-1 shows the results of compiling andrunning this program.
indicates that the program may use one or more types defined in theSystemnamespace .(Types are grouped into namespaces to help avoid name collisions andto group related types together.) Specifically, the hello, world program uses the Console class, which is defined inthe System namespace. The Imports statement ismerely a convenience. It is not needed if the developer is willing toqualify type names with their namespace names. For example, thehello, world program could have been writtenthis way:
In Visual Basic 6, various program objects were defined by placingsource code in files having various filename extensions. For example,code that defined classes was placed in .clsfiles, code that defined standard modules was placed in.bas files, and so on. In Visual Basic .NET, allsource files have .vb filename extensions, andprogram objects are defined with explicit syntax. For example,classes are defined with the Class...End Classconstruct, and standard modules are defined with theModule...End Module construct. Any particular.vb file can contain as many of thesedeclarations as desired.
Here is a program that uses a class instead of a standard module tohouse its Main subroutine. Note thatMain is declared with theShared modifier. It is compiled and run in thesame way as the standard module example, and it produces the sameoutput. There is no technical reason to choose one implementationover the other.
Besides the /references switch, the command linefor compiling the Hello, Windows programincludes the /target switch. The/target switch controls what kind of executablecode file is produced. The possible values of the/target switch are:
To run this program, enter it using a text editor and save it in afile named HelloBrowser.aspx. Because theapplication is a web page that is meant to be delivered by a webserver, it must be saved onto a machine that is running IIS and hasthe .NET Framework installed. Set up a virtual folder in IIS to pointto the folder containing HelloBrowser.aspx.Finally, point a web browser toHelloBrowser.aspx. The output of theHello, Browser application is shown in Figure 1-3.
The original Visual Basic (also referred to as Classic Visual Basic) is a third-generation event-driven programming language from Microsoft known for its Component Object Model (COM) programming model first released in 1991 and declared legacy during 2008. Microsoft intended Visual Basic to be relatively easy to learn and use. Visual Basic was derived from BASIC and enables the rapid application development (RAD) of graphical user interface (GUI) applications, access to databases using Data Access Objects, Remote Data Objects, or ActiveX Data Objects, and creation of ActiveX controls and objects.
A programmer can create an application using the components provided by the Visual Basic program itself. Over time the community of programmers developed third-party components. Programs written in Visual Basic can also make use of the Windows API, which requires external functions declarations.
The final release was version 6 in 1998. On April 8, 2008, Microsoft stopped supporting Visual Basic 6.0 IDE. The Microsoft Visual Basic team still maintains compatibility for Visual Basic 6.0 applications through its "It Just Works" program on supported Windows operating systems.
In 2014, some software developers still preferred Visual Basic 6.0 over its successor, Visual Basic .NET. Visual Basic 6.0 was selected as the most dreaded programming language by respondents of Stack Overflow's annual developer survey in 2016, 2017, and 2018.
Like the BASIC programming language, Visual Basic was designed to have an easy learning curve. Programmers can create both simple and complex GUI applications. Programming in VB is a combination of visually arranging components or controls on a form, specifying attributes and actions for those components, and writing additional lines of code for more functionality. Since VB defines default attributes and actions for the components, a programmer can develop a simple program without writing much code. Programs built with earlier versions suffered performance problems, but faster computers and native code compilation has made this less of an issue. Though VB programs can be compiled into native code executables from version 5 on, they still require the presence of around 1 MB of runtime libraries. Core runtime libraries are included by default in Windows 2000 and later, but extended runtime components still have to be installed. Earlier versions of Windows (95/98/NT), require that the runtime libraries be distributed with the executable.
Forms are created using drag-and-drop techniques. A tool is used to place controls (e.g., text boxes, buttons, etc.) on the form (window). Controls have attributes and event handlers associated with them. Default values are provided when the control is created, but may be changed by the programmer. Many attribute values can be modified during run time based on user actions or changes in the environment, providing a dynamic application. For example, code can be inserted into the form resize event handler to reposition a control so that it remains centered on the form, expands to fill up the form, etc. By inserting code into the event handler for a keypress in a text box, the program can automatically translate the case of the text being entered, or even prevent certain characters from being inserted.
Visual Basic can create executables (EXE files), ActiveX controls, or DLL files, but is primarily used to develop Windows applications and to interface with database systems. Dialog boxes with less functionality can be used to provide pop-up capabilities. Controls provide the basic functionality of the application, while programmers can insert additional logic within the appropriate event handlers. For example, a drop-down combination box automatically displays a list. When the user selects an element, an event handler is called that executes code that the programmer created to perform the action for that list item. Alternatively, a Visual Basic component can have no user interface, and instead provide ActiveX objects to other programs via Component Object Model (COM). This allows for server-side processing or an add-in module.
Visual Basic 1.0 was introduced in 1991. The drag and drop design for creating the user interface is derived from a prototype form generator developed by Alan Cooper and his company called Tripod. Microsoft contracted with Cooper and his associates to develop Tripod into a programmable form system for Windows 3.0, under the code name Ruby (no relation to the later Ruby programming language). Tripod did not include a programming language at all. Microsoft decided to combine Ruby with the Basic language to create Visual Basic. The Ruby interface generator provided the "visual" part of Visual Basic, and this was combined with the "EB" Embedded BASIC engine designed for Microsoft's abandoned "Omega" database system. Ruby also provided the ability to load dynamic link libraries containing additional controls (then called "gizmos"), which later became the VBX interface.
Earlier versions of Visual Basic (prior to version 5) compiled the code to P-Code only. The P-Code is interpreted by the language runtime. The benefits of P-Code include portability and smaller binary file sizes, but it usually slows down the execution, since having a runtime adds an additional layer of interpretation. Visual Basic applications require Microsoft Visual Basic runtime MSVBVMxx.DLL, where xx is the relevant version number, either 50 or 60. MSVBVM60.dll comes as standard with Windows in all editions from Windows 98 to Windows 10 (some editions of Windows 7 do not include it). A Windows 95 machine would however require inclusion with the installer of whichever DLL was needed by the program. Visual Basic 5 and 6 can compile code to either native or P-Code but in either case the runtime is still required for built in functions and forms management.
All versions of the Visual Basic development environment from 1.0 to 6.0 were retired by Microsoft by 2008, and are therefore no longer supported. The associated runtime environments are also unsupported, except for the Visual Basic 6 core runtime environment, which Microsoft officially supports for the lifetime of Windows 8, Windows 10 and Windows 11. Third party components that shipped with Visual Studio 6.0 are not included in this support statement. Some legacy Visual Basic components may still work on newer platforms, despite being unsupported by Microsoft and other vendors. Documentation for Visual Basic 6.0, its application programming interface and tools is best covered in the last MSDN release before Visual Studio.NET 2002. Later releases of MSDN focused on .NET development and had significant parts of the Visual Basic 6.0 programming documentation removed as the language evolved, and support for older code ended. Although vendor support for Visual Basic 6 has ended, and the product has never been supported on the latest versions of Windows, key parts of the environment still work on newer platforms. It is possible to get a subset of the development environment working on 32-bit and 64-bit versions of Windows Vista, Windows 7, Windows 8, Windows 10 and Windows 11. 2b1af7f3a8