Visual Basic .NET

Last updated

Visual Basic
VB.NET Logo.svg
Paradigm Multi-paradigm: structured, imperative, object-oriented, declarative, generic, reflective and event-driven
Designed by Microsoft
Developer Microsoft
First appeared2001;20 years ago (2001)
Stable release
2019 (16.0) / July 24, 2019;22 months ago (2019-07-24)
Typing discipline Static, both strong and weak, [1] both safe and unsafe, [1] nominative
Platform .NET Framework, Mono, .NET Core 3 [2]
OS Chiefly Windows
Also on Android, BSD, iOS, Linux, macOS, Solaris, and Unix
License Roslyn compiler: Apache License 2.0 [3]
Filename extensions .vb
Website docs.microsoft.com/dotnet/visual-basic/
Major implementations
.NET Framework SDK, Roslyn Compiler and Mono
Dialects
Microsoft Visual Basic
Influenced by
Classic Visual Basic
Influenced
Small Basic

Visual Basic, originally called Visual Basic .NET (VB.NET), is a multi-paradigm, object-oriented programming language, implemented on .NET, Mono, and the .NET Framework. Microsoft launched VB.NET in 2002 as the successor to its original Visual Basic language, the last version of which was Visual Basic 6.0. Although the ".NET" portion of the name was dropped in 2005, this article uses "Visual Basic [.NET]" to refer to all Visual Basic languages released since 2002, in order to distinguish between them and the classic Visual Basic. Along with C# and F#, it is one of the three main languages targeting the .NET ecosystem. As of March 11th, 2020, Microsoft announced that evolution of the VB.NET language has concluded. [4]

Contents

Microsoft's integrated development environment (IDE) for developing in Visual Basic is Visual Studio. Most Visual Studio editions are commercial; the only exceptions are Visual Studio Express and Visual Studio Community, which are freeware. In addition, the .NET Framework SDK includes a freeware command-line compiler called vbc.exe. Mono also includes a command-line VB.NET compiler.

Visual Basic is often used in conjunction with the Windows Forms GUI library to make desktop apps for Windows. Programming for Windows Forms with Visual Basic involves dragging and dropping controls on a form using a GUI designer and writing corresponding code for each control.

Syntax

Visual Basic uses statements to specify actions. The most common statement is an expression statement, consisting of an expression to be evaluated, on a single line. As part of that evaluation, functions or subroutines may be called and variables may be assigned new values. To modify the normal sequential execution of statements, Visual Basic provides several control-flow statements identified by reserved keywords. Structured programming is supported by several constructs including two conditional execution constructs (IfThenElseEnd If and Select Case ... Case ... End Select ) and three iterative execution (loop) constructs (DoLoop, ForTo, and For Each) . The ForTo statement has separate initialisation and testing sections, both of which must be present. (See examples below.) The For Each statement steps through each value in a list.

In addition, in Visual Basic:

Simple example

The following is a very simple Visual Basic program, a version of the classic "Hello, World!" example created as a console application:

ModuleModule1SubMain()' The classic "Hello, World!" demonstration programConsole.WriteLine("Hello, World!")EndSubEndModule

It prints "Hello, World!" on a command-line window. Each line serves a specific purpose, as follows:

ModuleModule1

This is a module definition. Modules are a division of code, which can contain any kind of object, like constants or variables, functions or methods, or classes, but can't be instantiated as objects like classes and cannot inherit from other modules. Modules serve as containers of code that can be referenced from other parts of a program. [6]
It is common practice for a module and the code file which contains it to have the same name. However, this is not required, as a single code file may contain more than one module and/or class.

SubMain()

This line defines a subroutine called "Main". "Main" is the entry point, where the program begins execution. [7]

Console.WriteLine("Hello, world!")

This line performs the actual task of writing the output. Console is a system object, representing a command-line interface (also known as a "console") and granting programmatic access to the operating system's standard streams. The program calls the Console method WriteLine, which causes the string passed to it to be displayed on the console.

Instead of Console.WriteLine, one could use MsgBox, which prints the message in a dialog box instead of a command-line window. [8]

Complex example

This piece of code outputs Floyd's Triangle to the console:

ImportsSystem.ConsoleModuleProgramSubMain()DimrowsAsInteger' Input validation.DoUntilInteger.TryParse(ReadLine("Enter a value for how many rows to be displayed: "&vbcrlf),rows)AndAlsorows>=1WriteLine("Allowed range is 1 and {0}",Integer.MaxValue)Loop' Output of Floyd's TriangleDimcurrentAsInteger=1DimrowAsIntegerDimcolumnAsIntegerForrow=1TorowsForcolumn=1TorowWrite("{0,-2} ",current)current+=1NextWriteLine()NextEndSub''' <summary>''' Like Console.ReadLine but takes a prompt string.''' </summary>FunctionReadLine(OptionalpromptAsString=Nothing)AsStringIfpromptIsNotNothingThenWrite(prompt)EndIfReturnConsole.ReadLine()EndFunctionEndModule

Comparison with the classic Visual Basic

Whether Visual Basic .NET should be considered as just another version of Visual Basic or a completely different language is a topic of debate. There are new additions to support new features, such as structured exception handling and short-circuited expressions. Also, two important data-type changes occurred with the move to VB.NET: compared to Visual Basic 6, the Integer data type has been doubled in length from 16 bits to 32 bits, and the Long data type has been doubled in length from 32 bits to 64 bits. This is true for all versions of VB.NET. A 16-bit integer in all versions of VB.NET is now known as a Short. Similarly, the Windows Forms editor is very similar in style and function to the Visual Basic form editor.

The things that have changed significantly are the semantics—from those of an object-based programming language running on a deterministic, reference-counted engine based on COM to a fully object-oriented language backed by the .NET Framework, which consists of a combination of the Common Language Runtime (a virtual machine using generational garbage collection and a just-in-time compilation engine) and a far larger class library. The increased breadth of the latter is also a problem that VB developers have to deal with when coming to the language, although this is somewhat addressed by the My feature in Visual Studio 2005.

The changes have altered many underlying assumptions about the "right" thing to do with respect to performance and maintainability. Some functions and libraries no longer exist; others are available, but not as efficient as the "native" .NET alternatives. Even if they compile, most converted Visual Basic 6 applications will require some level of refactoring to take full advantage of the new language. Documentation is available to cover changes in the syntax, debugging applications, deployment and terminology. [9]

Comparative examples

The following simple examples compare VB and VB.NET syntax. They assume that the developer has created a form, placed a button on it and has associated the subroutines demonstrated in each example with the click event handler of the mentioned button. Each example creates a "Hello, World" message box after the button on the form is clicked.

Visual Basic 6:

PrivateSubCommand1_Click()MsgBox"Hello, World"EndSub

VB.NET (MsgBox or MessageBox class can be used):

PrivateSubButton1_Click(senderAsobject,eAsEventArgs)HandlesButton1.ClickMsgBox("Hello, World")EndSub
  • Both Visual Basic 6 and Visual Basic .NET automatically generate the Sub and End Sub statements when the corresponding button is double-clicked in design view. Visual Basic .NET will also generate the necessary Class and End Class statements. The developer need only add the statement to display the "Hello, World" message box.
  • All procedure calls must be made with parentheses in VB.NET, whereas in Visual Basic 6 there were different conventions for functions (parentheses required) and subs (no parentheses allowed, unless called using the keyword Call).
  • The names Command1 and Button1 are not obligatory. However, these are default names for a command button in Visual Basic 6 and VB.NET respectively.
  • In VB.NET, the Handles keyword is used to make the sub Button1_Click a handler for the Click event of the object Button1. In Visual Basic 6, event handler subs must have a specific name consisting of the object's name ("Command1"), an underscore ("_"), and the event's name ("Click", hence "Command1_Click").
  • There is a function called MessageBox.Show in the Microsoft.VisualBasic namespace which can be used (instead of MsgBox) similarly to the corresponding function in Visual Basic 6. There is a controversy [10] about which function to use as a best practice (not only restricted to showing message boxes but also regarding other features of the Microsoft.VisualBasic namespace). Some programmers prefer to do things "the .NET way", since the Framework classes have more features and are less language-specific. Others argue that using language-specific features makes code more readable (for example, using int (C#) or Integer (VB.NET) instead of System.Int32).
  • In Visual Basic 2008, the inclusion of ByVal sender as Object, ByVal e as EventArgs has become optional.

The following example demonstrates a difference between Visual Basic 6 and VB.NET. Both examples close the active window.

Visual Basic 6:

SubcmdClose_Click()UnloadMeEndSub

VB.NET:

SubbtnClose_Click(senderAsObject,eAsEventArgs)HandlesbtnClose.ClickClose()EndSub

The 'cmd' prefix is replaced by the 'btn' prefix, conforming to the new convention previously mentioned.[ which? ]

Visual Basic 6 did not provide common operator shortcuts. The following are equivalent:

Visual Basic 6:

SubTimer1_Timer()'Reduces Form Height by one pixel per tickMe.Height=Me.Height-1EndSub

VB.NET:

SubTimer1_Tick(senderAsObject,eAsEventArgs)HandlesTimer1.TickMe.Height-=1EndSub

Comparison with C#

C# and Visual Basic are Microsoft's first languages made to program on the .NET Framework (later adding F# and more; others have also added languages). Though C# and Visual Basic are syntactically different, that is where the differences mostly end. Microsoft developed both of these languages to be part of the same .NET Framework development platform. They are both developed, managed, and supported by the same language development team at Microsoft. [11] They compile to the same intermediate language (IL), which runs against the same .NET Framework runtime libraries. [12] Although there are some differences in the programming constructs, their differences are primarily syntactic and, assuming one avoids the Visual Basic "Compatibility" libraries provided by Microsoft to aid conversion from Visual Basic 6, almost every feature in VB has an equivalent feature in C# and vice versa. Lastly, both languages reference the same Base Classes of the .NET Framework to extend their functionality. As a result, with few exceptions, a program written in either language can be run through a simple syntax converter to translate to the other. There are many open source and commercially available products for this task.

Examples

Hello World!

Windows Form Application

Requires a button called Button1.

PublicClassForm1PrivateSubButton1_Click(senderAsObject,eAsEventArgs)HandlesButton1.ClickMsgBox("Hello world!",MsgBoxStyle.Information,"Hello world!")' Show a message that says "Hello world!".EndSubEndClass
Hello world! window Hello world! Window.jpg
Hello world! window

Console Application

ModuleModule1SubMain()Console.WriteLine("Hello world!")' Write in the console "Hello world!" and start a new line.Console.ReadKey()' The user must press any key before the application ends.EndSubEndModule

Speaking

Windows Form Application

Requires a TextBox titled 'TextBox1' and a button called Button1.

PublicClassForm1PrivateSubButton1_Click(senderAsObject,eAsEventArgs)HandlesButton1.ClickCreateObject("Sapi.Spvoice").Speak(TextBox1.Text)EndSubEndClass

Console Application

ModuleModule1PrivateVoice=CreateObject("Sapi.Spvoice")PrivateTextAsStringSubMain()Console.Write("Enter the text to speak: ")' Say "Enter the text to speak: "Text=Console.ReadLine()' The user must enter the text to speak.Voice.Speak(Text)' Speak the text the user has entered.EndSubEndModule

Version history

Succeeding the classic Visual Basic version 6.0, the first version of Visual Basic .NET debuted in 2002. As of 2020, ten versions of Visual Basic .NET are released.

2002 (VB 7.0)

The first version, Visual Basic .NET, relies on .NET Framework 1.0. The most important feature is managed code, which contrasts with the classic Visual Basic.

2003 (VB 7.1)

Visual Basic .NET 2003 was released with .NET Framework 1.1. New features included support for the .NET Compact Framework and a better VB upgrade wizard. Improvements were also made to the performance and reliability of .NET IDE (particularly the background compiler) and runtime. In addition, Visual Basic .NET 2003 was available in the Visual Studio.NET Academic Edition, distributed to a certain number of scholars[ weasel words ] from each country without cost.

2005 (VB 8.0)

After Visual Basic .NET 2003, Microsoft dropped ".NET" from the name of the product, calling the next version Visual Basic 2005.

For this release, Microsoft added many features intended to reinforce Visual Basic .NET's focus as a rapid application development platform and further differentiate it from C#., including:

To bridge the gaps between itself and other .NET languages, this version added:

Visual Basic 2005 introduced the IsNot operator that makes 'If X IsNot Y' equivalent to 'If Not X Is Y'. It gained notoriety [18] when it was found to be the subject of a Microsoft patent application. [19] [20]

2008 (VB 9.0)

Visual Basic 9.0 was released along with .NET Framework 3.5 on November 19, 2007.

For this release, Microsoft added many features, including:

2010 (VB 10.0)

In April 2010, Microsoft released Visual Basic 2010. Microsoft had planned to use Dynamic Language Runtime (DLR) for that release [21] but shifted to a co-evolution strategy between Visual Basic and sister language C# to bring both languages into closer parity with one another. Visual Basic's innate ability to interact dynamically with CLR and COM objects has been enhanced to work with dynamic languages built on the DLR such as IronPython and IronRuby. [22] The Visual Basic compiler was improved to infer line continuation in a set of common contexts, in many cases removing the need for the " _" line continuation characters. Also, existing support of inline Functions was complemented with support for inline Subs as well as multi-line versions of both Sub and Function lambdas. [23]

2012 (VB 11.0)

Visual Basic 2012 was released alongside .NET Framework 4.5. Major features introduced in this version include:[ further explanation needed ]

2013 (VB 12.0)

Visual Basic 2013 was released alongside .NET Framework 4.5.1 with Visual Studio 2013. Can also build .NET Framework 4.5.2 applications by installing Developer Pack. [24]

2015 (VB 14.0)

Visual Basic 2015 (code named VB "14.0") was released with Visual Studio 2015. Language features include a new "?." operator to perform inline null checks, and a new string interpolation feature is included to format strings inline. [25]

2017 (VB 15.x)

Visual Basic 2017 (code named VB "15.0") was released with Visual Studio 2017. Extends support for new Visual Basic 15 language features with revision 2017, 15.3, 15.5, 15.8. Introduces new refactorings that allow organizing source code with one action. [26] [27]

2019 (VB 16.0)

Visual Basic 2019 (code named VB "16.0") was released with Visual Studio 2019. [28] The first version of Visual Basic focused on .NET Core. [29]

Cross-platform and open-source development

The official Visual Basic compiler is written in Visual Basic and is available on GitHub as a part of the .NET Compiler Platform. [30] The creation of open-source tools for Visual Basic development has been slow compared to C#, although the Mono development platform provides an implementation of Visual Basic-specific libraries and a Visual Basic 2005 compatible compiler written in Visual Basic, [31] as well as standard framework libraries such as Windows Forms GUI library.

SharpDevelop and MonoDevelop are open-source alternative IDEs. The Gambas environment is also similar but distinct from Visual Basic.

See also

Related Research Articles

BASIC Family of programming languages

BASIC is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use. The original version was designed by John G. Kemeny and Thomas E. Kurtz and released at Dartmouth College in 1964. They wanted to enable students in fields other than science and mathematics to use computers. At the time, nearly all use of computers required writing custom software, which was something only scientists and mathematicians tended to learn.

VBScript is an Active Scripting language developed by Microsoft that is modeled on Visual Basic. It allows Microsoft Windows system administrators to generate powerful tools for managing computers with error handling, subroutines, and other advanced programming constructs. It can give the user complete control over many aspects of their computing environment.

Visual Basic for Applications (VBA) is an implementation of Microsoft's event-driven programming language Visual Basic 6, which was declared legacy in 2008, and is an associated integrated development environment (IDE). Although pre-.NET Visual Basic is no longer supported or updated by Microsoft, the VBA programming language was upgraded in 2010 with the introduction of Visual Basic for Applications 7 in Microsoft Office applications. As of 2020, VBA has held its position as "most dreaded" language for developers for 2 years, according to some who participated in surveys undertaken by Stack Overflow..

Windows Script Host

The Microsoft Windows Script Host (WSH) is an automation technology for Microsoft Windows operating systems that provides scripting abilities comparable to batch files, but with a wider range of supported features. This tool was first provided on Windows 95 after Build 950a on the installation discs as an optional installation configurable and installable by means of the Control Panel, and then a standard component of Windows 98 and subsequent and Windows NT 4.0 Build 1381 and by means of Service Pack 4. The WSH is also a means of automation for Internet Explorer via the installed WSH engines from IE Version 3.0 onwards; at this time VBScript became means of automation for Microsoft Outlook 97. The WSH is also an optional install provided with a VBScript and JScript engine for Windows CE 3.0 and following and some third-party engines including Rexx and other forms of Basic are also available.

FreeBASIC

FreeBASIC is a multiplatform, free/open source (GPL) BASIC programming language and compiler for Microsoft Windows, protected-mode MS-DOS, Linux, FreeBSD and Xbox. The Xbox version is no longer maintained.

Windows Presentation Foundation (WPF) is a free and open-source graphical subsystem originally developed by Microsoft for rendering user interfaces in Windows-based applications. WPF, previously known as "Avalon", was initially released as part of .NET Framework 3.0 in 2006. WPF uses DirectX and attempts to provide a consistent programming model for building applications. It separates the user interface from business logic, and resembles similar XML-oriented object models, such as those implemented in XUL and SVG.

Managed Extensions for C++ or Managed C++ is a now-deprecated set of language extensions for C++, including grammatical and syntactic extensions, keywords and attributes, to bring the C++ syntax and language to the .NET Framework. These extensions were created by Microsoft to allow C++ code to be targeted to the Common Language Runtime (CLR) in the form of managed code, as well as continue to interoperate with native code.

C Sharp (programming language) Multi-paradigm (object-oriented) programming language

C# is a general-purpose, multi-paradigm programming language encompassing static typing, strong typing, lexically scoped, imperative, declarative, functional, generic, object-oriented (class-based), and component-oriented programming disciplines.

Oxygene (programming language)

Oxygene is a programming language developed by RemObjects Software for Microsoft's Common Language Infrastructure, the Java Platform and Cocoa. Oxygene based on Delphi's Object Pascal, but also has influences from C#, Eiffel, Java, F# and other languages.

C# and Visual Basic .NET are the two primary languages used to program on the .NET Framework.

Visual Basic Event-driven programming language

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.

This article describes the syntax of the C# programming language. The features described are compatible with .NET Framework and Mono.

typeof, alternately also typeOf, and TypeOf, is an operator provided by several programming languages to determine the data type of a variable. This is useful when constructing programs that must accept multiple types of data without explicitly specifying the type.

XBLite is a free Open Source BASIC programming language compiler and development system. It was started in 2001 by David Szafranski in order to provide a Windows exclusive version of the XBasic dialect. XBLite is released under the GNU GPL licensing scheme, Standard libraries are released under the GNU LGPL licensing scheme.

Microsoft Small Basic

Microsoft Small Basic is a programming language, interpreter and associated IDE. Microsoft's simplified variant of BASIC, it is designed to help students who have learnt visual programming languages such as Scratch learn text-based programming. The associated IDE provides a simplified programming environment with functionality such as syntax highlighting, intelligent code completion, and in-editor documentation access. The language has only 14 keywords.

The programming language C# introduces several new features in version 2.0. These include:

.NET Framework version history

Microsoft started development on the .NET Framework in the late 1990s originally under the name of Next Generation Windows Services (NGWS). By late 2001 the first beta versions of .NET 1.0 were released. The first version of .NET Framework was released on 13 February 2002, bringing managed code to Windows NT 4.0, 98, 2000, ME and XP.

Windows Runtime (WinRT) is a platform-agnostic application architecture first introduced in Windows 8 and Windows Server 2012 in 2012. WinRT supports development in C++/WinRT, C++/CX, Rust/WinRT, JavaScript-TypeScript, and the managed code languages C# and Visual Basic .NET (VB.NET). WinRT applications natively support both the x86 and ARM processors, and may run inside a sandboxed environment to allow greater security and stability. WinRT components are designed with interoperability among multiple languages and APIs in mind, including native, managed and scripting languages.

.NET Compiler Platform, also known by its nickname Roslyn, is a set of open-source compilers and code analysis APIs for C# and Visual Basic (VB.NET) languages from Microsoft.

Visual Basic .NET was released by Microsoft in 2002 as a successor to the original Visual Basic computer programming language. It was implemented on the .NET Framework 1.0. The main new feature was managed code. Programmers familiar only with Visual Basic would probably have encountered difficulties working with the new version or adapting existing programs for it.

References

  1. 1 2 "Option Explicit and Option Strict in Visual Basic .NET and in Visual Basic". Support. Microsoft. March 19, 2008. Retrieved August 22, 2013.
  2. Dollard, Kathleen (November 13, 2018). "Visual Basic in .NET Core 3.0". blogs.msdn.microsoft.com.
  3. "Dotnet/Roslyn".
  4. "Visual Basic support planned for .NET 5.0". March 11, 2020.
  5. "New Features in Visual Basic 10".
  6. "Module Statement". MSDN – Developer Center. Retrieved January 20, 2010.
  7. "Main Procedure in Visual Basic". MSDN – Developer Center. Retrieved January 20, 2010.
  8. "Visual Basic Version of Hello, World". MSDN – Developer Center. Retrieved January 20, 2010.
  9. "Microsoft Visual Basic 6.0 Migration Resource Center". MSDN . Microsoft . Retrieved November 9, 2014.
  10. "Visual Studio 2003 Retired Technical documentation". Microsoft Download Center.
  11. Krill, Paul (February 27, 2009). "Microsoft converging programming languages | Developer World". InfoWorld. Archived from the original on January 26, 2013. Retrieved August 18, 2013.
  12. "Microsoft Intermediate Language". Dotnet-guide.com. Retrieved August 18, 2013.
  13. Mackenzie, Duncan (2006). "Navigate The .NET Framework And Your Projects With The My Namespace". MSDN Magazine Visual Studio 2005 Guided Tour 2006. Microsoft.
  14. Whitney, Tyler (November 2005). "My.Internals: Examining the Visual Basic My Feature". MSDN . Microsoft.
  15. "What's New with the Visual Basic Upgrade Wizard in Visual Basic 2005". msdn2.microsoft.com.
  16. "Defining and Using Generics in Visual Basic 2005". msdn2.microsoft.com.
  17. "Operator Overloading in Visual Basic 2005". msdn2.microsoft.com.
  18. Sherriff, Lucy (February 22, 2005). "Real Software slams MS IsNot patent application". The Register. Retrieved April 6, 2009.
  19. Taft, Darryl K. (February 21, 2005). "Real Software Slams Microsofts Patent Effort". eWeek. Retrieved April 6, 2009.
  20. Vick, Paul A. Jr.; Barsan, Costica Corneliu; Silver, Amanda K. (May 14, 2003). "United States Patent Application: 20040230959". Patent Application Full Text and Image Database. US Patent & Trademark Office. Retrieved April 6, 2009.
  21. "What the heck is "VBx"?". May 1, 2007. Retrieved August 12, 2009. With the new DLR, we have support for IronPython, IronRuby, Javascript, and the new dynamic VBx compile
  22. "What is New in Visual Basic 2010". Microsoft. 2009. Retrieved August 12, 2009. Visual Basic binds to objects from dynamic languages such as IronPython and IronRuby
  23. "What's New in Visual Basic 2010". Microsoft. 2010. Retrieved August 1, 2010.
  24. Download Microsoft .NET Framework 4.5.2 Developer Pack for Windows Vista SP2, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2008 SP2 Windows Server 2008 R2 SP1, Windows Server 2012 and Windows Server 2012 R2 from Official Microsoft Download Center
  25. "New Language Features in Visual Basic 14". msdn.com.
  26. reshmim. "Visual Studio 2017 Release Notes". www.visualstudio.com.
  27. reshmim. "What's new for Visual Basic 2017,15.3,15.5,15.8". www.visualstudio.com.
  28. reshmim. "Visual Studio 2019 Release Notes". www.visualstudio.com.
  29. reshmim. "What's new for Visual Basic 16.0". www.visualstudio.com.
  30. Roslyn, .NET Foundation, April 13, 2019, retrieved April 14, 2019
  31. "Redirecting…". www.mono-project.com.

Further reading

  1. "Visual Basic Language Specification 8.0". Microsoft Corporation. November 15, 2005. Retrieved December 10, 2010.
  2. "Visual Basic Language Specification 9.0". Microsoft Corporation. December 19, 2007. Retrieved September 28, 2011.
  3. "Visual Basic Language Specification 11.0". Microsoft Corporation. June 7, 2013. Retrieved September 22, 2013.