C# and Visual Basic .NET are the two primary languages used to program on the .NET Framework.
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C# and VB.NET are syntactically very different languages with very different history. As the name suggests, the C# syntax is based on the core C language originally developed by Bell Labs (AT&T) in the 1970s [1] and eventually evolved into the fully object oriented C++ language still in use today. Much of the Java syntax is also based on this same C++ language,[2] which is one of the reasons the two share a common look and feel. See Comparison of Java and C Sharp for more on this topic.
VB.NET has its roots in the BASIC language of the '60s with its name being an acronym for "Beginner's All-purpose Symbolic Instruction Code". In its beginning, BASIC was used in the college community as a "basic" language for first exposure to computer programming and the acronym represented the language accurately.[3] In the '70s, the language was picked up by microcomputer manufacturers of the era to be used as both a simple ROM embedded programming language as well as a quasi operating system for input/output control.[4] In the early '80s, the language was picked up by Microsoft and expanded significantly beyond its original intent into their "Visual Basic" language/platform that was sold throughout the 1990s as a "rapid application development" (RAD) tool for Windows programming.[5] It competed directly against other RAD tools of the 1990s such as PowerBuilder.[6] Even though Visual Basic was a successful development platform, it was discontinued after its 6th version (VB6) when Microsoft introduced the .NET Framework and its related Visual Studio development platform in the early 2000s.
Though C# and VB.NET are syntactically very 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.[7] They compile to the same intermediate language (IL), which runs against the same .NET Framework runtime libraries.[8] Although there are some differences in the programming constructs (discussed further below), their differences are primarily syntactic and, assuming one avoids the Visual Basic "Compatibility" libraries provided by Microsoft to aid conversion from VB6, almost every command in VB has an equivalent command 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 purpose.
One of the main goals of .NET has been its multi-language support. The intent of the design was that all of the various Microsoft languages should have the same level of access to all OS features, should be able to expose the same level of power and usability, and simplify calling from a module in one language to that written in another language.
In implementation, all .NET programming languages share the same runtime engine, uniform Abstract syntax tree, and Common Intermediate Language. Additionally all .NET languages have access to platform features including garbage collection, cross language inheritance, exception handling, and debugging. This allows the same output binary to be produced from any .NET programming language.
Visual Studio provides minor differences in the development environment for C# and VB.Net. With each subsequent release of Visual Studio, the differences between development environments for these languages have been reduced. For instance early versions of Visual Studio had poor support for Intellisense in C# compared to Visual Basic .NET, and did not offer background compilation for C#.[9] Currently, the main differences in the development environments are additional features for Visual Basic .NET that originated in VB6, including:
My.* namespaces contain many commonly-used shortcuts brought over from VB6, such as methods for operating on the registry and application configuration fileBackground compilation is a feature of the Visual Studio IDE whereby code is compiled as it is written by the programmer with the purpose of identifying compilation errors without requiring the solution to be built. This feature has been available for Visual Basic since .NET 1.1 and was present in early versions of Visual Studio for Visual Basic .NET. However, background compilation is a relatively new concept for Visual C# and is available with service pack 1 for Visual Studio 2008 Standard Edition and above. A distinct disadvantage for C# is that the Error List panel does not update until the solution is rebuilt. Refactoring large projects in C# is made more difficult by the need to frequently rebuild the solution in order to highlight compilation errors.[10] Such is not the case with Visual Basic because the Error List panel is synchronised with the background compiler.
Background Compilation is less demanding on system resources and results in faster build cycles.[10] This is a particular advantage with large projects and can significantly reduce the time required to start debugging in the IDE.[10]
The bulk of the differences between C# and VB.NET from a technical perspective are syntactic sugar.That is, most of the features are in both languages, but some things are easier to do in one language than another. Many of the differences between the two languages are actually centered around the IDE.
WithEvents construct. This construct is available so that a programmer may select an object from the Class Name drop down list and then select a method from the Declarations drop down list to have the Method signature automatically insertedHandles syntax for eventsWith ... End With structureIsNumeric evaluates whether a string can be cast into a numeric value (the equivalent for C# requires using int.TryParse)#1/1/2000# syntax (M/dd/yyyy).Module (although C#'s sealed static classes with additional semantics, but each field has to individually be declared as static)Modules imported to the current file, can be access with no preceding container accessor (See Now for example)My namespacedynamic type which functions as a late bound form of Object.unsafe keywordchecked and unchecked contexts for fine-grained control of overflow/underflow checking=. Whereas C# has separate tokens, == for comparison and = to assign a valueDim i As Integer = "1" 'Compiler automatically converts String to Integer Dim j As String = 1 'Compiler automatically converts Integer to String If i = j Then 'Compiler does cast and compare between i and j MessageBox.Show("Avoid using, but this message will appear!") End If
It should be noted that although the default is for 'Option Strict' is off, it is recommended by Microsoft[14] and widely considered to be a good practice to turn 'Option Strict' "on", due to the fact it increases application performance, and eliminates the chance of naming errors and other programming mistakes.[15]
Val() function which also parses a null value while converting into double (In c# Convert.ToDouble() is used to convert any object into double type value, but which throws exception in case of a null value)Visual Basic .NET terminates a block of code with End BlockName statements (or Next statements, for a for loop) which are more familiar for programmers with experience using T-SQL. In C#, the braces, {}, are used to delimit blocks, which is more familiar to programmers with experience in other widely-deployed languages such as C++ and Java. Additionally, in C# if a block consists of only a single statement, the braces may be omitted.
C# is case sensitive while Visual Basic .NET is not. Thus in C# it is possible to have two variables with the same name, for example variable1 and Variable1. Visual Studio will correct the case of variables as they are typed in VB.NET. In many cases however, case sensitivity can be useful. C# programmers typically capitalize type names and leave member and variable names lowercase. This allows, for example, fairly natural naming of method arguments: public int CalculateOrders(Customer customer). Of course, this can cause problems for those converting C# code to a case-insensitive language, such as Visual Basic, or to those unaccustomed to reading a case sensitive language.
Visual Basic is not case sensitive, which means any combinations of upper and lower cases in keywords are acceptable. However Visual Studio automatically converts all Visual Basic keywords to the default capitalised forms, e.g. "Public", "If".
C# is case sensitive and all C# keywords are in lower cases.
Visual Basic and C# share most keywords, with the difference being the default (Remember Visual Basic is not case sensitive) Visual Basic keywords are the capitalised versions of the C# keywords, e.g. "Public" vs "public", "If" vs "if".
A few keywords have very different versions in Visual Basic and C#:
Friend vs internal - access modifiers allowing inter-class but not intra-assembly referenceMe vs this - a self-reference to the current object instanceMustInherit vs abstract - prevents a class from being directly instantiated, and forces consumers to create object references to only derived classesMustOverride vs abstract - for forcing derived classes to override this methodMyBase vs base - for referring to the base class from which the current class is derivedNotInheritable vs sealed - for declaring classes that may not be inheritedNotOverridable vs sealed - for declaring methods that may not be overridden by derived classesOverridable vs virtual - declares a method as being able to be overridden in derived classesShared vs static - for declaring methods that do not require an explicit instance of an objectSome C# keywords such as sealed represent different things when applied to methods as opposed to when they are applied to class definitions. VB.NET, on the other hand, uses different keywords for different contexts.
| C# | Visual Basic .NET |
|---|---|
//Single line comment /*Multi-line comment line 2 line 3*/ ///XML single line comment /**XML multi-line comment line 2 line 3*/ |
'Single line comment
Multi-line comment not available
'''XML single line comment
XML multi-line comment not available |
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| C# | Visual Basic .NET |
if (condition) { // condition is true } else if (othercondition) { // condition is false and othercondition is true } else { // condition and othercondition are false } |
If condition Then ' condition is true ElseIf othercondition Then ' condition is false and othercondition is true Else ' condition and othercondition false End If |
| C# | Visual Basic .NET |
for (int i = 0; i <= number - 1; i++) { // loop from zero up to one less than number } |
For i As Integer = 0 To number - 1 ' loop from zero up to one less than number Next |
for (int i = number; i >= 0; i--) { // loops from number down to zero } |
For i As Integer = number To 0 Step -1 ' loops from number down to zero Next |
break; //breaks out of a loop |
Exit For 'breaks out of a for loop Exit While 'breaks out of a while loop Exit Do 'breaks out of a do loop |
| C# | Visual Basic .NET | |
if (a == b) { // equal } |
If a = b Then ' equal End If |
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if (a != b) { // not equal } Or: if (!(a == b)) { // not equal } |
If a <> b Then ' not equal End If Or: If Not a = b Then ' not equal End If |
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if (a == b & c == d | e == f) { // multiple comparisons } |
If a = b And c = d Or e = f Then ' multiple comparisons End If |
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if (a == b && c == d || e == f) { // short-circuiting comparisons } |
If a = b AndAlso c = d OrElse e = f Then ' short-circuiting comparisons End If |
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| C# | Visual Basic .NET |
if (Object.ReferenceEquals(a, b)) { // variables refer to the same instance } |
If a Is b Then 'Can also be written as If Object.ReferenceEquals(a, b) Then ' variables refer to the same instance End If |
if (!Object.ReferenceEquals(a, b)) { // variables do not refer to the same instance } |
If a IsNot b Then ' variables do not refer to the same instance End If |
if (a.Equals(b)) { // instances are equivalent } |
If a = b Then 'Or a.Equals(b) ' instances are equivalent End If |
if (! a.Equals(b)) { // not equivalent } |
If a <> b Then ' not equivalent End If |
var type = typeof(int); |
Dim type = GetType(Integer) |
if (a is b) { // types of a and b are compatible } |
If TypeOf a Is b Then ' types of a and b are compatible End If |
if (!(a is b)) { // types of a and b are not compatible } |
If Not TypeOf a Is b Then ' types of a and b are not compatible End If |
Note: these examples for equivalence tests assume neither the variable "a" nor the variable "b" is a Null reference (Nothing in Visual Basic.NET). If "a" were null, the C# evaluation of the .equals method would throw a NullReferenceException, whereas the VB.NET = operator would return true if both were null, or false if only one was null (and evaluate the equals method if neither were null). They also assume that the .equals method and the = operator are implemented for the class type in question. Omitted for clarity, the exact transliteration would be:
C#
if(object.equals(a,b))
VB.NET
If a = b Then
Both C# and VB.NET have high adoption rates, and very active developer communities and Microsoft fully supports both communities. Most .NET Framework developers use C# as their primary language.[16] C# has an advantage in terms of the level of community activity on the Internet and there are more books available for C#.
Examples of community and industry adoption include:
C++/CLI (a replacement for Managed Extensions for C++) does not have the adoption rate of C# or VB.NET, but does have a significant following. C++/CLI syntactically, stylistically, and culturally is closest to C#. However, C++/CLI stays closer to its C++ roots than C# does. C++/CLI directly supports pointers, destructors, and other unsafe program concepts which are not supported or limited in the other languages. It allows the direct use of both .NET code and standard C++ code. C++/CLI is used for porting native/legacy C++ applications into the .NET framework, or cases where the programmer wants to take more control of the code; but this control comes at a significant cost of ease of use and readability. Many of the automated tools that come with Visual Studio have reduced functionality when interacting with C++ code. This is because reflection cannot provide as much information about the code as it can for C# and VB.net
J# runs a distant fourth in terms of adoption. J# is a language primarily designed to ease the transition of Java applications to the .NET framework; it allows developers to leave much of their Java or J++ code unchanged while still running it in the .NET framework, thus allowing them to migrate small pieces of it into another .NET language, such as C#, individually. J# does not receive the same level of updates as the other languages, and does not have the same level of community support. For example, Visual Studio 2005 Team System supports automatic generation of Unit Tests in C#, VB.Net, and C++, but excludes J#. J# has been discontinued and is not included in Visual Studio 2008 or newer versions, since the existing J# feature set largely meets customer needs and usage of J# is declining.
All .NET languages compile down to Common Intermediate Language (CIL), which contains rich metadata and is functionally and logically equivalent to the original .NET language code. For these reasons, while it is possible to code directly in CIL, it is rarely done. The equivalency of CIL to .NET language code permits tools such as .NET Reflector to transform a .NET assembly into source code that is nearly identical to the original source. Code obfuscators are often used to guard against this, and operate by directly modifying the CIL of an assembly in order to make it difficult or impossible to de-compile to a higher level .NET language.
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