Visual Basic (.NET)

This article is about the modern programming language for.NET. For the original Visual Basic, the last version of which was Visual Basic 6.0, seeVisual Basic (classic).

Visual Basic(VB), originally calledVisual Basic.NET(VB.NET), is amulti-paradigm,object-orientedprogramming language,implemented on.NET,Mono,and the.NET Framework.Microsoft launched VB.NET in 2002 as the successor to itsoriginal Visual Basiclanguage, 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 theclassic Visual Basic.Along withC#andF#,it is one of the three main languages targeting the.NET ecosystem. Microsoft updated its VB language strategy on 6 February 2023, stating that VB is a stable language now and Microsoft will keep maintaining it.

Visual Basic

Paradigm	Multi-paradigm:structured,imperative,object-oriented,declarative,generic,reflectiveandevent-driven
Designed by	Microsoft
Developer	Microsoft
First appeared	2001(2001)
Stable release	16.9 / 2 March 2024(2 March 2024)
Typing discipline	Static,both strong and weak,both safe and unsafe,nominative
Platform	.NET Framework,Mono,.NET
OS	ChieflyWindows Also onAndroid,BSD,iOS,Linux,macOS,Solaris,andUnix
License	Roslyncompiler:MIT License
Filename extensions	.vb
Website	docs.microsoft.com/dotnet/visual-basic/
Majorimplementations
.NET Framework SDK,Roslyn CompilerandMono
Dialects
Microsoft Visual Basic
Influenced by
Classic Visual Basic
Influenced
Small Basic,Mercury

Microsoft'sintegrated development environment(IDE) for developing in Visual Basic isVisual Studio.Most Visual Studio editions arecommercial;the only exceptions areVisual Studio ExpressandVisual Studio Community,which arefreeware.In addition, the.NET Framework SDKincludes a freewarecommand-linecompilercalled vbc.exe.Monoalso includes a command-line VB.NET compiler.

Visual Basic is often used in conjunction with theWindows FormsGUIlibraryto makedesktop appsforWindows.Programming for Windows Forms with Visual Basic involves dragging and dropping controls on a form using aGUI designerand writing corresponding code for each control.

Use in making GUI programs

See also:Windows Forms

The Windows Forms library is most commonly used to create GUI interfaces in Visual Basic. All visual elements in the Windows Forms class library derive from the Control class. This provides the minimal functionality of a user interface element such as location, size, color, font, text, as well as common events like click and drag/drop. The Control class also has docking support to let a control rearrange its position under its parent.

Forms are typically designed in theVisual StudioIDE.In Visual Studio, forms are created usingdrag-and-droptechniques. A tool is used to place controls (e.g., text boxes, buttons, etc.) on the form (window). Controls haveattributesandevent handlersassociated 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.

Syntax

Visual Basic usesstatementsto specify actions. The most common statement is an expression statement, consisting of anexpressionto be evaluated, on a single line. As part of that evaluation,functions or subroutinesmay becalledandvariablesmay beassignednew values. To modify the normal sequential execution of statements, Visual Basic provides several control-flow statements identified by reserved keywords.Structured programmingis supported by several constructs including two conditional execution constructs (If...Then...Else...End IfandSelect Case...Case...End Select) and four iterative execution (loop) constructs (Do...Loop,For...To,For Each,andWhile...End While). TheFor...Tostatement has separate initialisation and testing sections, both of which must be present. (See examples below.) TheFor Eachstatement steps through each value in a list.

In addition, in Visual Basic:

• There is no unified way of defining blocks of statements. Instead, certain keywords, such as "If… Then" or "Sub" are interpreted as starters of sub-blocks of code and have matching termination keywords such as "End If" or "End Sub".
• Statements are terminated either with acolon( ":" ) or with theend of line.Multiple-line statements in Visual Basic are enabled with "_" at the end of each such line. The need for the underscore continuation character was largely removed in version 10 and later versions.
• Theequals sign( "=" ) is used in both assigning values to variables and in comparison.
• Round brackets(parentheses) are used witharrays,both to declare them and to get a value at a given index in one of them. Visual Basic uses round brackets to define the parameters of subroutines or functions.
• Asingle quotation mark(') or the keywordREM,placed at the beginning of a line or after any number ofspaceortabcharacters at the beginning of a line, or after other code on a line, indicates that the (remainder of the) line is acomment.

Simple example

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

ModuleModule1

SubMain()
' The classic "Hello, World!" demonstration program
Console.WriteLine("Hello, World!")
EndSub

EndModule

It prints "Hello, World!"on acommand-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 not 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.
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 or class.

SubMain()

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

Console.WriteLine("Hello, world!")

This line performs the actual task of writing the output.Consoleis a system object, representing a command-line interface (also known as a "console" ) and granting programmatic access to the operating system'sstandard streams.The program calls theConsolemethodWriteLine,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.

Complex example

This piece of code outputsFloyd's Triangleto the console:

ImportsSystem.Console

ModuleProgram

SubMain()
DimrowsAsInteger

' Input validation.
DoUntilInteger.TryParse(ReadLine("Enter a value for how many rows to be displayed:"&vbcrlf),rows)AndAlsorows>=1
WriteLine("Allowed range is 1 and {0}",Integer.MaxValue)
Loop

' Output of Floyd's Triangle
DimcurrentAsInteger=1
DimrowAsInteger
DimcolumnAsInteger
Forrow=1Torows
Forcolumn=1Torow
Write("{0,-2}",current)
current+=1
Next

WriteLine()
Next
EndSub

''' <summary>
''' Like Console.ReadLine but takes a prompt string.
''' </summary>
FunctionReadLine(OptionalpromptAsString=Nothing)AsString
IfpromptIsNotNothingThen
Write(prompt)
EndIf

ReturnConsole.ReadLine()
EndFunction

EndModule

Comparison with the classic Visual Basic

Main article:Comparison of Visual Basic and Visual Basic.NET

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 asstructured exception handlingand short-circuited expressions. Also, two important data-type changes occurred with the move to VB.NET: compared to Visual Basic 6, theIntegerdata typehas been doubled in length from 16 bits to 32 bits, and theLongdata typehas 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 aShort.Similarly, theWindows Formseditor is very similar in style and function to the Visual Basic form editor.

The things thathavechanged significantly are the semantics—from those of an object-based programming language running on adeterministic,reference-countedengine based onCOMto a fullyobject-orientedlanguage backed by the.NET Framework,which consists of a combination of theCommon Language Runtime(avirtual machineusinggenerational garbage collectionand ajust-in-time compilationengine) and a far largerclass 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 theMyfeature 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 ofrefactoringto take full advantage of the new language. Documentation is available to cover changes in the syntax, debugging applications, deployment and terminology.

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 clickevent handlerof 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.Click
MsgBox("Hello, World")
EndSub

• Both Visual Basic 6 and Visual Basic.NET automatically generate theSubandEnd Substatements when the corresponding button is double-clicked in design view. Visual Basic.NET will also generate the necessaryClassandEnd Classstatements. 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 keywordCall).
• The namesCommand1andButton1are not obligatory. However, these are default names for a command button in Visual Basic 6 and VB.NET respectively.
• In VB.NET, theHandleskeyword is used to make the subButton1_Clicka handler for theClickevent of the objectButton1.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,henceCommand1_Click).
• There is a function calledMessageBox.Showin theMicrosoft.VisualBasicnamespace which can be used (instead ofMsgBox) similarly to the corresponding function in Visual Basic 6. There is a controversyabout which function to use as a best practice (not only restricted to showing message boxes but also regarding other features of theMicrosoft.VisualBasicnamespace). 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, usingint(C#) orInteger(VB.NET) instead ofSystem.Int32).
• In Visual Basic 2008, the inclusion ofByValsenderasObject,ByValeasEventArgshas become optional.

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

Visual Basic 6:

SubcmdClose_Click()
UnloadMe
EndSub

VB.NET:

SubbtnClose_Click(senderAsObject,eAsEventArgs)HandlesbtnClose.Click
Close()
EndSub

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

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 tick
Me.Height=Me.Height-1
EndSub

VB.NET:

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

Comparison with C#

Main article:Comparison of C Sharp and Visual Basic.NET

C# and Visual Basic are Microsoft's first languages made to program on the.NET Framework (later addingF#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.They compile to the same intermediate language (IL), which runs against the same.NET Framework runtime libraries.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 Forms Application

Requires a button called Button1.

PublicClassForm1

PrivateSubButton1_Click(senderAsObject,eAsEventArgs)HandlesButton1.Click
MsgBox("Hello world!",MsgBoxStyle.Information,"Hello world!")' Show a message that says "Hello world!".
EndSub
EndClass

Hello world! window

Console Application

ModuleModule1

SubMain()
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.
EndSub
EndModule

Speaking

Windows Forms Application

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

PublicClassForm1

PrivateSubButton1_Click(senderAsObject,eAsEventArgs)HandlesButton1.Click
CreateObject("Sapi.Spvoice").Speak(TextBox1.Text)
EndSub
EndClass

Console Application

ModuleModule1
PrivateVoice=CreateObject("Sapi.Spvoice")
PrivateTextAsString

SubMain()
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.
EndSub
EndModule

Version history

Succeedingthe classic Visual Basicversion 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 ismanaged 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 Frameworkand a better VB upgradewizard.Improvements were also made to the performance and reliability of.NET IDE (particularly thebackground compiler) and runtime. In addition, Visual Basic.NET 2003 was available in the Visual Studio.NET Academic Edition, distributed to a certain number of scholarsfrom 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 arapid application developmentplatform and further differentiate it fromC#., including:

• Edit and Continuefeature
• Design-time expression evaluation
• A pseudo-namespacecalled "My", which provides:
  • Easy access to certain areas of the.NET Framework that otherwise require significant code to access like usingMy.Form2.Text="MainForm"rather thanSystem.WindowsApplication1.Forms.Form2.text="MainForm"
  • Dynamically generated classes (e.g.My.Forms)
• Improved VB-to-VB.NET converter
• A "using" keyword, simplifying the use of objects that require the Disposepatternto free resources
• Just My Codefeature, which hides (steps over)boilerplate codewritten by the Visual Studio.NET IDE and system library code during debugging
• Data Source binding, easingdatabaseclient/server development

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

• Generics
• Partial classes,a method of defining some parts of a class in one file and then adding more definitions later; particularly useful for integrating user code with auto-generated code
• Operator overloadingandnullable types
• Support forunsigned integerdata types commonly used in other languages

Visual Basic 2005 introduced theIsNotoperator that makes'If X IsNot Y'equivalent to'If Not X Is Y'.It gained notorietywhen it was found to be the subject of a Microsoft patent application.

2008 (VB 9.0)

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

For this release, Microsoft added many features, including:

• A trueconditional operator,"If(condition as Boolean, truepart, falsepart)", to replace the "IIf" function.
• Anonymous types
• Support forLINQ
• Lambda expressions
• XML Literals
• Type Inference
• Extension methods

2010 (VB 10.0)

In April 2010, Microsoft released Visual Basic 2010. Microsoft had planned to useDynamic Language Runtime(DLR) for that releasebut 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 asIronPythonandIronRuby.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.

2012 (VB 11.0)

Visual Basic 2012 was released alongside.NET Framework 4.5.Major features introduced in this version include:

• Asynchronous programmingwith "async" and "await" statements
• Iterators
• Call hierarchy
• Caller information
• "Global" keyword in "namespace" statements

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.

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.

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.

2019 (VB 16.0)

Visual Basic 2019 (code named VB "16.0" ) was released with Visual Studio 2019.It is the first version of Visual Basic focused on.NET Core.

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.The creation of open-source tools for Visual Basic development has been slow compared toC#,although theMonodevelopment platform provides an implementation of Visual Basic-specific libraries and a Visual Basic 2005 compatiblecompilerwritten in Visual Basic,as well as standard framework libraries such asWindows FormsGUI library.

MonoDevelopwas anopen-sourcealternativeIDE.TheGambasenvironment is also similar but distinct from Visual Basic, as is the Visual FB Editor forFreeBasic.

See also

• Microsoft Visual Studio Express
• List of.NET libraries and frameworks
• Comparison of C# and Visual Basic.NET
• Visual Basic for Applications
• Microsoft Small Basic
• Comparison of programming languages

References

• "License.txt in the Roslyn repo at 0d04884".GitHub.RetrievedNovember 26,2024.{{cite web}}:CS1 maint: url-status (link)

Further reading

1. "Visual Basic Language Specification 8.0".Microsoft Corporation. November 15, 2005.Archivedfrom the original on January 21, 2011.RetrievedDecember 10,2010.
2. "Visual Basic Language Specification 9.0".Microsoft Corporation. December 19, 2007.RetrievedSeptember 28,2011.
3. "Visual Basic Language Specification 11.0".Microsoft Corporation. June 7, 2013.Archivedfrom the original on March 5, 2012.RetrievedSeptember 22,2013.

External links

• Official website
• The Visual Basic Team Blog