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December 7, 2007 / kiranpatils

Differences between visual basic .net and Visual c# .net

Syntactically, Visual Basic .NET and Visual C# .NET are two different languages, just as Visual Basic, Visual C, and Visual C++ are different languages. Visual C# .NET looks more familiar to Visual C, Visual C++, and Java programmers, and Visual Basic .NET looks more familiar to Visual Basic developers. The biggest differences between the languages fall into the following categories:

  • Case sensitivity
  • Variable declaration and assignment
  • Data types
  • Statement termination
  • Statement blocks
  • Use of () vs. []
  • Operators
  • Conditional statements
  • Error handling
  • Overflow checking
  • Parameter passing
  • Late binding
  • Handling unmanaged code
  • Keywords

Case Sensitivity

Identifier names in Visual Basic .NET are not case-sensitive, but identifier names in Visual C# .NET are. This primarily presents a problem when you write code, and is not an issue in debugging a program that already compiles.

Variable Declaration and Assignment

Variables in Visual Basic .NET are declared with the variable before the data type. In Visual C# .NET, the data type precedes the variables.

Visual Basic .NET Visual C# .NET
Dim i, j As Integer int i, j;
Dim i As Integer = 7 int i = 7;
Dim i(6) As Integeror

Dim i() As Integer = New Integer(6) {}

int[] i = new int[6];
Dim con As SqlConnection SqlConnection con;
Dim x As New Y(“ABC”)or

Dim x As Y = New Y(“ABC”)

Y x = new Y(“ABC”);

Data Types

Simple data types have different names in Visual Basic .NET and Visual C# .NET. For example, Integer in Visual Basic .NET is int in Visual C# .NET. However, System.Int32, the .NET Framework base type for which Integer and int are aliases, can be used in both languages. Visual C# .NET also supports the signed byte, unsigned short, unsigned int, and unsigned long data types, which are not available in Visual Basic .NET.

The following table lists the different data type names in each language and the base types for which they are aliases.

Visual Basic .NET Visual C# .NET .NET Framework
Boolean bool System.Boolean
Byte byte System.Byte
Short short System.Int16
Integer int System.Int32
Long long System.Int64
Single float System.Single
Double double System.Double
Decimal decimal System.Decimal
Date System.DateTime System.DateTime
String string System.String
Char char System.Char
Object object System.Object
n/a sbyte System.Sbyte
n/a ushort System.UInt16
n/a uint System.UInt32
n/a ulong System.UInt64

Statement Termination

Statements in Visual Basic .NET are terminated by the end of the line. You can use the colon (:) to put multiple statements in a line, and you can use the line continuation (_) character to make a statement span several lines.

Statements in Visual C# .NET are terminated by the semicolon (;). You can use multiple statements per line, and statements can span multiple lines.

Visual Basic .NET Visual C# .NET
A = 5B = 7 : C = 8

MySub (Arg1, _

Arg2, _

Arg3)

A = 5;B = 7; C = 8;

MySub (Arg1,

Arg2,

Arg3);

Statement Blocks

Visual Basic .NET does not use arbitrary statement blocks. Instead, certain keywords that have a specialized terminating statement are used instead of the statement blocks.

In Visual C# .NET, braces ({}) are used to delimit a statement block; otherwise, a single statement is assumed.

Visual Basic .NET Visual C# .NET
If A = 5 ThenDoSomething()

DoSomethingAgain()

End If

If (a == 5){

DoSomething();

DoSomethingAgain();

}

or

if (a == 5)

DoSomething();

DoSomethingAgain(); //This is not part of

//the if statement.

Use of () vs. [ ]

Visual Basic .NET uses parentheses () to delimit array elements, function arguments, and property indexes.

Visual C# .NET uses parentheses () to delimit function arguments, and brackets ([]) to delimit array elements and property indexes.

Purpose Visual Basic .NET Visual C# .NET
Declare an array Dim a() As LongDim a(3, 5) as Integer int[] x = new int[5];
Initialize an array Dim a() As Long = {3, 4, 5} int[] x = new int[5] {1, 2, 3, 4, 5};
Reallocate array Redim n/a
Functions Arguments X= A(5)MySub (A, B, C) MySub(A, B, C);
Property Indexes Y = MyDataSet.Tables_ (“Author”).Rows(5)._Columns(“AuthorID”) Y = MyDataSet.Tables[“Author”].Rows[5].Columns[“AuthorID”]

Operators

The operators that are used in Visual Basic .NET and Visual C# .NET are quite different. The following table lists the main operators. This information can also be found in the Microsoft® Visual Studio .NETTM documentation.

  Operator Visual Basic .NET Visual C# .NET   Additive    
  Addition + +
  Subtraction
  Multiplicative    
  Multiplication * *
  Division / /
  Integer division \ / (depending on the operands)
  Modulus (division returning only the remainder) Mod %
  Exponentiation ^ n/a
  Assignment    
  Assignment =+= -= *= /* =+= -= *= /*
Integer division \= /= (depending on the operands)  
Concatenate &= +=  
Modulus n/a %=  
Left shift n/a <<=  
Right shift n/a >>=  
Bitwise AND n/a &=  
XOR n/a ^=  
OR n/a |=  
Relational and equality      
Less than < <  
Less than or equal to <= <=  
Greater than > >  
Greater than or equal to >= >=  
Equal = ==  
Not equal <> !=  
Compare two object reference variables Is ==  
Compare object reference type TypeOf x Is Class1 x is Class1  
Compare strings = == or String.Equals()  
Concatenate strings & +  
Shortcircuited Boolean AND AndAlso &&  
Shortcircuited Boolean OR OrElse ||  
Shift      
Left shift n/a <<  
Right shift n/a >>  
Scope resolution      
Scope resolution . ., base  
Postfix      
Type cast Cint, CDbl, …, CType (type)  
Member selection . .  
Postfix increment n/a ++  
Postfix decrement n/a  
Unary      
Indirection n/a * (unsafe mode only)  
Address of AddressOf & (unsafe mode only)  
Logical NOT Not !  
One’s complement Not ~  
Prefix increment n/a ++  
Prefix decrement n/a  
Size of type n/a sizeof  
Bitwise      
Bitwise NOT Not ~  
Bitwise AND And &  
Bitwise XOR Xor ^  
Bitwise OR Or |  
Logical      
Logical AND, OR And &&  
Logical OR Or ||  
Conditional      
Conditional IIf ?:  
Pointer to member      
Pointer to member n/a . (Unsafe mode only)  

Conditional Statements

The following table lists the differences in the conditional statements that Visual Basic .NET and Visual C# .NET use.

Conditional Statement Visual Basic .NET Visual C# .NET
Decision structure (selection) Select Case …, Case, Case Else, End Select switch, case, default,
Decision structure (if … then) If … Then, ElseIf … Then, Else, End If if, else
Loop structure (conditional) While… End While, Do [While, Until] …, Loop [While, Until] do, while, continue
Loop structure (iteration) For …, [Exit For,] NextFor Each …, [Exit For,] Next for, foreach
Control flow statement Exit, GoTo, Stop, End, Return, break, continue, goto, return,throw

Error Handling

Unstructured error handling is for backward compatibility. Visual Basic .NET supports both structured and unstructured error handling, but Visual C# .NET supports only structured error handling.

Purpose Visual Basic .NET Visual C# .NET
Structured error handling Try…
Catch

Finally

End Try

try, catch, finally,
throw
Unstructured error handling On Error GoTo …On Error Resume Next n/a

Overflow Checking

Visual Basic .NET has a project level setting to check for overflow. However, the checking can only be turned on and off at the project level, instead of at the level of an expression or a block of code. To turn overflow checking on and off, follow these steps:

1. On the Project menu, click Properties.

2. Under Configuration Properties, select Optimizations, and then select or clear Remove integer overflow checks.

Visual C# .NET statements can run in either a checked or an unchecked context. In a checked context, arithmetic overflow raises an exception error. In an unchecked context, arithmetic overflow is ignored and the result is truncated. This can be used on an expression or a block of code.

Parameter Passing

Visual Basic .NET uses ByVal for passing parameters by value, and uses ByRef for passing parameters by reference. Visual Basic .NET can also force parameters to be passed by value, regardless of how they are declared, by enclosing the parameters in extra parentheses. Visual Basic .NET also supports optional parameters, which are not available in Visual C# .NET.

Visual C# .NET does not have a way to pass reference types (objects) strictly by value. You can either pass the reference (basically a pointer) or a reference to the reference (a pointer to a pointer). Unmanaged Visual C# .NET methods can take pointers just like Visual C++ methods. To pass a parameter by reference, Visual C# .NET uses the ref keyword. To use a ref parameter, the argument must explicitly be passed to the method as a ref argument. The value of a ref argument is passed to the ref parameter.

Purpose Visual Basic .NET Visual C# .NET
Pass by value Public Sub ABC (ByVal y As Long)…

End Sub

ABC(x)

ABC((x))

void ABC(int x){

}

ABC(i);

Pass by reference Public Sub ABC(ByRef y As Long)…

End Sub

ABC(x)

void ABC(ref int x){

}

ABC(ref i);

Optional parameter Supported n/a

Late Binding

Both Visual Basic .NET and Visual C# .NET can implement implicit late binding through reflection. However, implementing late binding in Visual Basic .NET is much easier than in Visual C# .NET.

In Visual Basic .NET, as in Visual Basic 6.0, the Visual Basic compiler calls a helper method behind the scenes that uses reflection to obtain the object type. The arguments that are passed to the helper method cause the appropriate method to be invoked at run time. These arguments are the object on which to invoke the method, the name of the invoked method that is a string, and the arguments that are passed to the invoked method that is an array of objects. Additionally, you can implement late binding explicitly in code through reflection.

Imports System

Module Hello

Sub Main()

‘ Set up variable.

Dim helloObj As Object

‘ Create the object.

helloObj = new HelloWorld()

‘ Invoke the print method as if it was early bound

‘ even though it is really late bound.

helloObj.PrintHello(“Visual Basic Late Bound”)

End Sub

End Module

In Visual C# .NET, implementing late binding is more difficult than in Visual Basic .NET. Instead of having the compiler implement late binding, you must explicitly implement late binding in code by using reflection.

Handing Unmanaged Code

Visual C# .NET permits you to write unmanaged code. In unmanaged code, you can do things such as declare and operate on pointers, perform conversions between pointers and integral types, and take the address of variables. In a sense, writing unmanaged code is much like writing Visual C code in a Visual C# .NET program.

Because code that is written by using an unmanaged context cannot be verified to be safe, it is run only when the code is fully trusted. Do not use unmanaged context to try to write Visual C code in Visual C# .NET. Unmanaged code must be clearly marked with the modifier unsafe so that developers cannot use unmanaged features accidentally, and the execution engine works to make sure that unmanaged code cannot be run in a non-trusted environment. The scope of the unmanaged context extends from the parameter list to the end of the function, so pointers can also be used in the parameter list.

In Visual Basic .NET, you cannot write unmanaged code.

Keywords

The following table lists the keywords that Visual Basic .NET and Visual C# .NET use in several categories. This information can also be found in the Visual Studio .NET online documentation.

  Purpose Visual Basic .NET Visual C# .NET     Object Oriented Programming      
  Indicates a class constructor Public Class Class1Public Sub New(..)

MyBase.New

End Sub

End Class

Note: You have to call the base class constructor explicitly in Visual Basic .NET.

public class Class1{

public Class1(..)

{

}

….

}

Note: The call to the base class constructor (base()) is generated automatically by the compiler in Visual C# .NET if you do not include constructor initializers.

 
  Indicates a class destructorNote: The Destructor or Finalize method is called by garbage collection. Protected Overrides Sub Finalize()m_Gadget = Nothing

m_Gear = Nothing

MyBase.Finalize()

End Sub

public class Class1{

public ~Class1()

{

….

}

}

 
  Declares a class Class class  
  Indicates class inheritance Public Class AInherits B

End Class

public class A : B{

}

 
  Indicates that the class can only be inherited and cannot be instantiated MustInherit abstract  
  Indicates that the class cannot be inherited NotInheritable sealed  
  Calls your own implementation of the method instead of an overridden method in the derived class MyClass None  
  Refers to a base class from the derived class MyBase base  
  Declares a type-safe reference to a class method Delegate delegate  
  Indicates that the method or the property overrides the implementation in its base class Overrides override  
  Indicates that these methods have no implementation and must be implemented in derived classes MustOverride(in MustInherit

class)

abstract(in abstract

class)

 
  Indicates that the method or the property cannot be overridden in derived classes NotOverridableNote: By default, methods are not overridable. sealed  
  Indicates that the method or the property can be overridden in an inheriting class Overridable virtual  
  Overloads a procedure, a function, or a method Overloads None. Define functions with same name but different signatures.  
  Specifies that a variable can contain an object whose events you want to handle WithEvents No specific keyword  
  Specifies the events for which an event procedure will be called Handles (Event procedures can still be associated with a WithEvents variable by naming pattern.) n/a  
  Evaluates an object expression one time to access multiple members With objExpr<.member>

<.member>

End With

n/a  
  Refers to the current object Me This  
  Declares an enumerated type Enum…

End Enum

Enum  
  Declares an interface Interface interface  
  Implements an interface Implements class C1 : I1  
  Indicates an indexer Default Property public string this[int index]{

get {return List[index];}

set {List[index]=value;}

}

 
  Class Access Modifiers      
  Indicates that the modifier is accessible outside the project or the assembly Public public  
  Indicates that the modifier is accessible inside the assembly only Friend internal  
  Indicates that the modifier is accessible only in the project (for nested classes, in the enclosing class) Private private  
  Class Member Access Modifiers      
  Indicates that the modifier is accessible outside the class and the project Public public  
  Indicates that the modifier is accessible outside the class, but in the project Friend internal  
  Indicates that the modifier is only accessible in a class or a module Private private  
  Indicates that the modifier is accessible only to current and derived classes Protected protected  
  Indicates the union of Protected and Friend or Internal Protected Friend protected internal  
  Indicates that the members are shared across all instances Shared static  
  Miscellaneous Lifetime      
  Preserves the local variables for the procedure Static n/a  
  Other      
Calls the Windows API Declare statement use Platform Invoke  
Indicates a comment ‘, Rem //, /* */ for miltine comments,/// for XML comments  
Indicates a constant Const Const, readonly  
  Creates a new object New, CreateObject new
  Declares a function or a method with no return value Sub void
  Declares that an object can be modified asynchronously n/a volatile
  Declares a variable Private, Public, Friend, Protected, Static, Shared, Dim declarators (keywords include user-defined types and built-in types)
  Declares a variable explicitly Option Explicit None (All variables must be declared before use)
  Declares and raises an event Event, RaiseEvent event
  Declares a structure Structure…

End Structure

struct
  Defines a default property Default by using indexers
  Declares a null object Nothing null
  Declares a namespace Namespace…

End Namespace

Namespace{

}

  Indicates namespace usage Imports using
  Retrieves a character from a string GetChar Function [ ]
  Returns the address of a function AddressOf (For class members, this operator returns a reference to a function in the form of a delegate instance) delegate
  Tests for a null object Obj Is Nothing obj == null
  Tests for a database null expression IsDbNull n/a
  Threads primitives SyncLock lock

Conclusion

Based on your personal preference and past experience, you can use either Visual Basic .NET or Visual C# .NET to build solutions. Although differences do exist between the two languages, both languages use the .NET Framework common language runtime and are equally powerful. This document only briefly discusses the differences in syntax between Visual Basic .NET and Visual C# .NET. For more detailed information about these differences and other differences that exist between the two programming languages, see the Visual Studio .NET online help.

One Comment

Leave a Comment
  1. music / Jan 7 2008 7:34 pm

    very interesting.
    i’m adding in RSS Reader

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