Visual Basic

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Visual Basic
VisualBasicLogo.gif
Microsoft Visual Studio 6 screenshot.png
Screenshot of the Visual Basic 6 IDE running on Windows Vista.
Paradigm(s)Object-based and Event-driven
Appeared in1991; 23 years ago (1991)
DeveloperMicrosoft
Stable release6.0 (1998; 16 years ago (1998))
Typing disciplineStatic, strong
Major implementationsMicrosoft Visual Studio
Influenced byBASIC
InfluencedVisual Basic .NET, Gambas, REALbasic and Basic4ppc
OSMicrosoft Windows and MS-DOS
Websitemsdn.microsoft.com/en-us/vstudio/ms788229.aspx
 
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Visual Basic
VisualBasicLogo.gif
Microsoft Visual Studio 6 screenshot.png
Screenshot of the Visual Basic 6 IDE running on Windows Vista.
Paradigm(s)Object-based and Event-driven
Appeared in1991; 23 years ago (1991)
DeveloperMicrosoft
Stable release6.0 (1998; 16 years ago (1998))
Typing disciplineStatic, strong
Major implementationsMicrosoft Visual Studio
Influenced byBASIC
InfluencedVisual Basic .NET, Gambas, REALbasic and Basic4ppc
OSMicrosoft Windows and MS-DOS
Websitemsdn.microsoft.com/en-us/vstudio/ms788229.aspx

Visual Basic is a third-generation event-driven programming language and integrated development environment (IDE) from Microsoft for its COM programming model first released in 1991. Microsoft intends Visual Basic to be relatively easy to learn and use.[1][2] 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. Programs written in Visual Basic can also use the Windows API, but doing so requires external function declarations. Though the program has received criticism for its perceived faults,[3] version 3 of Visual Basic was a commercial success,[citation needed] and many companies offered third party controls greatly extending its functionality.

The final release was version 6 in 1998. Microsoft's extended support ended in March 2008 and the designated successor was Visual Basic .NET (now known simply as Visual Basic).

Though Visual Basic 6.0 is no longer officially available there remains a sizable number of developers who still prefer Visual Basic 6.0 over .NET.[citation needed]

A dialect of Visual Basic, Visual Basic for Applications (VBA), is used as a macro or scripting language within several Microsoft applications, including Microsoft Office.[4]

Language features[edit]

Like the BASIC programming language, Visual Basic was designed to accommodate beginner programmers. Programmers can not only create simple GUI applications, but to also develop complex 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. Runtime libraries are included by default in Windows 2000 and later. Earlier versions of Windows (95/98/NT), require that the runtime libraries be distributed with the executable.

An empty form in Visual Basic 6.

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 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.

The runtime recovers unused memory using reference counting, which depends on variables passing out of scope or being set to Nothing, avoiding the problem of memory leaks common to other languages. There is a large library of utility objects, and the language provides basic object oriented support. Unlike many other programming languages, Visual Basic is generally not case sensitive—though it transforms keywords into a standard case configuration and forces the case of variable names to conform to the case of the entry in the symbol table. String comparisons are case sensitive by default.

The Visual Basic compiler is shared with other Visual Studio languages (C, C++), but restrictions in the IDE do not allow creation of some targets (Windows model DLLs) and threading models.

Characteristics[edit]

The code windows in Visual Basic, showing a Function using the If, Then, Else and Dim statements.

The following Visual Basic traits differ from C-derived languages:

OPTION BASE was introduced by ANSI, with the standard for ANSI Minimal BASIC in the late 1970s.

History[edit]

Alan Cooper created the drag and drop design for the user interface of Visual Basic.

VB 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 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.[8]

Timeline Description[edit]

Basic for MS-DOS
VB DOS icon

Derivative languages[edit]

Microsoft has developed derivatives of Visual Basic for use in scripting. Visual Basic itself is derived heavily from BASIC, and subsequently has been replaced with a .NET platform version.

Some of the derived languages are:

Performance and other issues[edit]

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. However, small amounts of code and algorithms can be constructed to run faster than compiled native code.

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 after Windows 98 while MSVBVM50.dll comes with all editions after Windows 95. 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.

Criticisms levelled at Visual Basic editions prior to VB.NET include:[19]

Legacy development and support[edit]

All versions of the Visual Basic development environment from 1.0 to 6.0 are now retired and unsupported by Microsoft. 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.[22] 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.

Development and maintenance development for Visual Basic 6 is possible on legacy Windows XP, Windows Vista and Windows 2003 using Visual Studio 6.0 platforms, but is unsupported. 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. The Visual Basic IDE can be installed and used on Windows Vista, where it exhibits some minor incompatibilities that do not hinder normal software development and maintenance. As of August 2008, both Visual Studio 6.0 and the MSDN documentation mentioned above are available for download by MSDN subscribers.

Example code[edit]

The following code snippet displays a message box saying "Hello, World!" as the window loads:

 Private Sub Form_Load()     ' Execute a simple message box that says "Hello, World!"     MsgBox "Hello, World!"End Sub 

This snippet makes a counter that moves up 1 every second (a label and a timer control need to be added to the form for this to work):

 Option Explicit Dim Count As Integer Private Sub Form_Load()     Count = 0     Timer1.Interval = 1000 ' units of milliseconds End Sub Private Sub Timer1_Timer()     Count = Count + 1     Label1.Caption = Count End Sub 

See also[edit]

Related Microsoft technologies:

Related programming languages:

References[edit]

  1. ^ Root, Randal; Romero Sweeney, Mary (2006). A tester's guide to .NET programming. Apress. p. 3. ISBN 978-1-59059-600-5. "You can choose a language based on how easy it is to learn. For beginners, Visual Basic is a good choice. [~snip] A big advantage of Visual Basic is that it is a popular language because it is easy to learn." 
  2. ^ Plant, Robert T.; Murrell, Stephen (2007). An executive's guide to information technology. Cambridge University Press. p. 343. ISBN 978-0-521-85336-1. "Summary of positive issues: Visual Basic is easy to learn and widely available." 
  3. ^ "Thirteen Ways to Loathe VB". 
  4. ^ "VBA for Office Developers". Microsoft. 
  5. ^ In most languages, True is mapped to a non zero numeric value, often 1 or -1.
  6. ^ "Microsoft Basic Logical Expression Evaluation". Vb.mvps.org. Retrieved 2009-06-16. 
  7. ^ "PRB: Round Function different in VBA 6 and Excel Spreadsheet". Microsoft Support. Retrieved 2014-01-25. 
  8. ^ "The Birth of Visual Basic".  Rian " Petot " Danao I <3 19
  9. ^ www.insteptech.com (2005-07-22). "What's new in VB6?". www.insteptech.com. 
  10. ^ "Support Statement for Visual Basic 6.0 on Windows Vista, Windows Server 2008 and Windows 7". Msdn.microsoft.com. 2008-04-08. Retrieved 2009-06-16. 
  11. ^ "Support Statement for Visual Basic 6.0 on Windows Vista, Windows Server 2008, Windows 7, and Windows 8". Msdn.microsoft.com. 2012-11-01. Retrieved 2013-07-21. 
  12. ^ "Product Family Life Cycle Guidelines for Visual Basic 6.0". Msdn2.microsoft.com. 2005-03-31. Retrieved 2009-06-16. 
  13. ^ "Petition to Microsoft". Classicvb.org. 2005-03-08. Retrieved 2009-06-16. 
  14. ^ Al Tenhundfeld (2009-03-04). "Visual Basic 6.0 to be Supported on Windows 7". The Register. Retrieved 2009-03-05. 
  15. ^ Andrew Orlowski and Carey Bishop (2005-07-22). "MS Anti-Spyware built on MS Abandonware". The Register. Retrieved 2006-10-04. 
  16. ^ "Paul Thurrott's SuperSite for Windows: Windows Defender Beta 2 Review". Winsupersite.com. 2006-02-14. Retrieved 2009-06-16. 
  17. ^ "Compatibility Between the 32-bit and 64-bit Versions of Office 2010". Microsoft Corporation. Retrieved 16 July 2012. 
  18. ^ Piquet, Lori (2002-02-20). "Abandoning the Fantasy of VB Migration Wizardry". DevX.com. Jupitermedia. Retrieved 2007-05-17. 
  19. ^ Alex Homer, Dave Sussman, Rob Howard, Brian Francis, Karli Watson, Richard Anderson (2004). Professional ASP.NET 1.1. Wiley. p. 71. ISBN 0-7645-5890-0. Retrieved 2008-10-08. 
  20. ^ Marc D'Aoust (December 2000). "Avoid Writing Tedious, Boring Code". Microsoft. Retrieved 2008-11-10. 
  21. ^ Andrew Troelsen (2008). Pro VB 2008 and the .NET 3.5 Platform: The expert's voice in .NET. Apress. p. 5. ISBN 1-59059-822-9. 
  22. ^ Platt, David (2012-06-01). "Don't Get Me Started – The Silent Majority: Why Visual Basic 6 Still Thrives". MSDN Magazine. Retrieved 2012-06-09. 

External links[edit]