Microsoft.NET

……………………………………………….Expertise in .NET Technologies

Complete Comparison for VB.NET and C#

Posted by Ravi Varma Thumati on March 16, 2009

Contents

  1. Introduction
  2. Advantages of both languages
  3. Keyword Differences
  4. Data types Differences
  5. Operators Differences
  6. Programming Difference
  7. New Features of both languages in 2005 version
  8. Conclusion
  9. History

Introduction

Some people like VB.NET’s natural language, case-insensitive approach, others like C#’s terse syntax. But both have access to the same framework libraries. We will discuss about the differences in the following topics:

  1. Advantages of both languages
  2. Keyword Differences
  3. Data types Differences
  4. Operators Differences
  5. Programming Difference

Advantages of both languages

VB.NET C#
  • Support for optional parameters – very handy for some COM interoperability.
  • Support for late binding with Option Strict off – type safety at compile time goes out of the window, but legacy libraries which don’t have strongly typed interfaces become easier to use.
  • Support for named indexers.
  • Various legacy VB functions (provided in the Microsoft.VisualBasic namespace, and can be used by other languages with a reference to the Microsoft.VisualBasic.dll). Many of these can be harmful to performance if used unwisely, however, and many people believe they should be avoided for the most part.
  • The with construct: it’s a matter of debate as to whether this is an advantage or not, but it’s certainly a difference.
  • Simpler (in expression – perhaps more complicated in understanding) event handling, where a method can declare that it handles an event, rather than the handler having to be set up in code.
  • The ability to implement interfaces with methods of different names. (Arguably this makes it harder to find the implementation of an interface, however.)
  • CatchWhen … clauses, which allow exceptions to be filtered based on runtime expressions rather than just by type.
  • The VB.NET parts of Visual Studio .NET compiles your code in the background. While this is considered as an advantage for small projects, people creating very large projects have found that the IDE slows down considerably as the project gets larger.
  • XML documentation generated from source code comments. (This is coming in VB.NET with Whidbey (the code name for the next version of Visual Studio and .NET), and there are tools which will do it with existing VB.NET code already.)
  • Operator overloading – again, coming to VB.NET in Whidbey.
  • Language support for unsigned types (you can use them from VB.NET, but they aren’t in the language itself). Again, support for these is coming to VB.NET in Whidbey.
  • The using statement, which makes unmanaged resource disposal simple.
  • Explicit interface implementation, where an interface which is already implemented in a base class can be re-implemented separately in a derived class. Arguably this makes the class harder to understand, in the same way that member hiding normally does.
  • Unsafe code. This allows pointer arithmetic etc, and can improve performance in some situations. However, it is not to be used lightly, as a lot of the normal safety of C# is lost (as the name implies). Note that unsafe code is still managed code, i.e., it is compiled to IL, JITted, and run within the CLR.

Keyword Differences

Purpose VB.NET C#
Declare a variable Private, Public, Friend, Protected, Static1, Shared, Dim declarators (keywords include user-defined types and built-in types)
Declare a named constant Const const
Create a new object New, CreateObject() new
Function/method does not return a value Sub void
Overload a function or method (Visual Basic: overload a procedure or method) Overloads (No language keyword required for this purpose)
Refer to the current object Me this
Make a nonvirtual call to a virtual method of the current object MyClass n/a
Retrieve character from a string GetChar Function []
Declare a compound data type (Visual Basic: Structure) Structure <members> End Structure struct, class, interface
Initialize an object (constructors) Sub New() Constructors, or system default type constructors
Terminate an object directly n/a n/a
Method called by the system just before garbage collection reclaims an object7 Finalize destructor
Initialize a variable where it is declared  

Dim x As Long = 5
Dim c As New _
   Car(FuelTypeEnum.Gas)

 

 

// initialize to a value:
int x = 123;
// or use default
// constructor:
int x = new int();

 

Take 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
Declare that an object can be modified asynchronously n/a volatile
Force explicit declaration of variables Option Explicit n/a. (All variables must be declared prior to use)
Test for an object variable that does not refer to an object obj = Nothing obj == null
Value of an object variable that does not refer to an object Nothing null
Test for a database null expression IsDbNull n/a
Test whether a Variant variable has been initialized n/a n/a
Define a default property Default by using indexers
Refer to a base class MyBase base
Declare an interface Interface interface
Specify an interface to be implemented Implements (statement) class C1 : I1
Declare a class Class <implementation> class
Specify that a class can only be inherited. An instance of the class cannot be created. MustInherit abstract
Specify that a class cannot be inherited NotInheritable sealed
Declare an enumerated type Enum <members> End Enum enum
Declare a class constant Const const (Applied to a field declaration)
Derive a class from a base class Inherits C2 class C1 : C2
Override a method Overrides override
Declare a method that must be implemented in a deriving class MustOverride abstract
Declare a method that can’t be overridden NotOverridable (Methods are not overridable by default.) sealed
Declare a virtual method, property (Visual Basic), or property accessor (C#, C++) Overridable virtual
Hide a base class member in a derived class Shadowing n/a
Declare a typesafe reference to a class method Delegate delegate
Specify that a variable can contain an object whose events you wish to handle WithEvents (Write code – no specific keyword)
Specify 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
Evaluate an object expression once, in order to access multiple members  

With objExpr
  <.member>
  <.member>
End With

 

n/a
Structured exception handling  

Try <attempt>
Catch
<handle errors>
Finally
<always execute>
End Try

 

try, catch, finally, throw
Decision structure (selection) Select Case ..., Case, Case Else, End Select switch, case, default, goto, break
Decision structure (if … then) If ... Then, ElseIf ... Then, Else, End If if, else
Loop structure (conditional) While, Do [While, Until] ..., Loop [While, Until] do, while, continue
Loop structure (iteration) For ..., [Exit For], Next
For Each ..., [Exit For,] Next
for, foreach
Declare an array  

Dim a() As Long

 

 

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
Visible outside the project or assembly Public public
Invisible outside the assembly (C#/Visual Basic) or within the package (Visual J#, JScript) Friend internal
Visible only within the project (for nested classes, within the enclosing class) Private private
Accessible outside class and project or module Public public
Accessible outside the class, but within the project Friend internal
Only accessible within class or module Private private
Only accessible to current and derived classes Protected protected
Preserve procedure’s local variables Static n/a
Shared by all instances of a class Shared static
Comment code '
Rem
//, /* */ for multi-line comments
/// for XML comments
Case-sensitive? No Yes
Call Windows API Declare <API> use Platform Invoke
Declare and raise an event Event, RaiseEvent event
Threading primitives SyncLock lock
Go to Goto goto

Data types Differences

Purpose/Size VB.NET C#
Decimal Decimal decimal
Date Date DateTime
(varies) String string
1 byte Byte byte
2 bytes Boolean bool
2 bytes Short, Char (Unicode character) short, char (Unicode character)
4 bytes Integer int
8 bytes Long long
4 bytes Single float
8 bytes Double double

Operators Differences

Purpose VB.NET C#
Integer division \ /
Modulus (division returning only the remainder) Mod %
Exponentiation ^ n/a
Integer division Assignment \= /=
Concatenate &= NEW +=
Modulus n/a %=
Bitwise-AND n/a &=
Bitwise-exclusive-OR n/a ^=
Bitwise-inclusive-OR n/a |=
Equal = ==
Not equal <> !=
Compare two object reference variables Is ==
Compare object reference type TypeOf x Is Class1 x is Class1
Concatenate strings & +
Shortcircuited Boolean AND AndAlso &&
Shortcircuited Boolean OR OrElse ||
Scope resolution . . and base
Array element () [ ]
Type cast Cint, CDbl, …, CType (type)
Postfix increment n/a ++
Postfix decrement n/a --
Indirection n/a * (unsafe mode only)
Address of AddressOf & (unsafe mode only; also see fixed)
Logical-NOT Not !
One’s complement Not ~
Prefix increment n/a ++
Prefix decrement n/a --
Size of type n/a sizeof
Bitwise-AND And &
Bitwise-exclusive-OR Xor ^
Bitwise-inclusive-OR Or |
Logical-AND And &&
Logical-OR Or ||
Conditional If Function () ?:
Pointer to member n/a . (Unsafe mode only)

Programming Difference

 

Purpose VB.NET C#
Declaring Variables
Dim x As Integer
Public x As Integer = 10
int x;
int x = 10;

 

Comments
' comment
x = 1  ' comment
Rem comment
// comment
/* multiline
 comment */
Assignment Statements
nVal = 7
nVal = 7;
Conditional Statements
If nCnt <= nMax Then
   ' Same as nTotal =
   ' nTotal + nCnt.
   nTotal += nCnt
   ' Same as nCnt = nCnt + 1.
   nCnt += 1
Else
   nTotal += nCnt
   nCnt -= 1
End If
if (nCnt <= nMax)
{
   nTotal += nCnt;
   nCnt++;
}
else
{
   nTotal +=nCnt;
   nCnt--;
}
Selection Statements
Select Case n
   Case 0
      MsgBox ("Zero")
     ' Visual Basic .NET exits
     ' the Select at
     ' the end of a Case.
   Case 1
      MsgBox ("One")
   Case 2
      MsgBox ("Two")
   Case Else
      MsgBox ("Default")
End Select
switch(n)
{
   case 0:
      Console.WriteLine("Zero");
      break;
   case 1:
      Console.WriteLine("One");
      break;
   case 2:
      Console.WriteLine("Two");
      break;
   default:
      Console.WriteLine("?");
      break;
}
FOR Loops
For n = 1 To 10
   MsgBox("The number is " & n)
Next

For Each prop In obj
    prop = 42
Next prop
for (int i = 1; i <= 10; i++)
   Console.WriteLine(
      "The number is {0}", i);
foreach(prop current in obj)
{
   current=42;
}
Hiding Base Class Members
Public Class BaseCls
   ' The element to be shadowed
   Public Z As Integer = 100
   public Sub Test()
      System.Console.WriteLine( _
        "Test in BaseCls")
   End Sub
End Class

Public Class DervCls
   Inherits BaseCls
   ' The shadowing element.
   Public Shadows Z As String = "*"
   public Shadows Sub Test()
      System.Console.WriteLine( _
          "Test in DervCls")
   End Sub
End Class

Public Class UseClasses
  ' DervCls widens to BaseCls.
  Dim BObj As BaseCls =
          New DervCls()
  ' Access through derived
  ' class.
  Dim DObj As DervCls =
       New DervCls()

  Public Sub ShowZ()
    System.Console.WriteLine( _
     "Accessed through base "&_
     "class: "  & BObj.Z)
    System.Console.WriteLine(_
    "Accessed through derived "&_
    "class: " & DObj.Z)
    BObj.Test()
    DObj.Test()
  End Sub
End Class
public class BaseCls
{
   // The element to be hidden
   public int Z = 100;
   public void Test()
   {
      System.Console.WriteLine(
        "Test in BaseCls");
   }
}

public class DervCls : BaseCls
{
  // The hiding element
  public new string Z = "*";
  public new void Test()
  {
    System.Console.WriteLine(
      "Test in DervCls");
  }
}

public class UseClasses
{
  // DervCls widens to BaseCls
  BaseCls BObj = new DervCls();
   // Access through derived
   //class
  DervCls DObj = new DervCls();
  public void ShowZ()
  {
    System.Console.WriteLine(
    "Accessed through " +
      "base class: {0}",
      BObj.Z);
    System.Console.WriteLine(
    "Accessed through" +
      " derived class:{0}",
      DObj.Z);
    BObj.Test();
    DObj.Test();
   }
}
WHILE Loops
' Test at start of loop
While n < 100 .
   ' Same as n = n + 1.
   n += 1
End While '
while (n < 100)
   n++;
Parameter Passing by Value
' The argument Y is
'passed by value.
Public Sub ABC( _
  ByVal y As Long)
'If ABC changes y, the
' changes do not affect x.
End Sub

ABC(x) ' Call the procedure.
' You can force parameters to
' be passed by value,
' regardless of how
' they are declared,
' by enclosing
' the parameters in
' extra parentheses.
ABC((x))
/* Note that there is
no way to pass reference
types (objects) strictly
by value. You can choose
to either pass the reference
(essentially a pointer), or
a reference to the reference
(a pointer to a pointer).*/
// The method:
void ABC(int x)
{
   ...
}
// Calling the method:
ABC(i);
Parameter Passing by Reference
Public Sub ABC(ByRef y As Long)
' The parameter y is declared
'by referece:
' If ABC changes y, the changes are
' made to the value of x.
End Sub

ABC(x) ' Call the procedure.
/* Note that there is no
 way to pass reference types
 (objects)  strictly by value.
 You can choose to  either
 pass the reference
 (essentially  a pointer),
 or a reference to the
 reference (a pointer to a
 pointer).*/
// Note also that unsafe C#
//methods can take pointers
//just like C++ methods. For
//details, see unsafe.
// The method:
void ABC(ref int x)
{
   ...
}
// Calling the method:
ABC(ref i);
Structured Exception Handling
Try
   If x = 0 Then
      Throw New Exception( _
         "x equals zero")
   Else
      Throw New Exception( _
        "x does not equal zero")
   End If
Catch err As System.Exception
   MsgBox( _
   "Error: " & Err.Description)
Finally
   MsgBox( _
   "Executing finally block.")
End Try
// try-catch-finally
try
{
  if (x == 0)
   throw new System.Exception(
     "x equals zero");
  else
   throw new System.Exception(
     "x does not equal zero");
}
catch (System.Exception err)
{
  System.Console.WriteLine(
              err.Message);
}
finally
{
  System.Console.WriteLine(
   "executing finally block");
}
Set an Object Reference to Nothing
o = Nothing
o = null;
Initializing Value Types
Dim dt as New System.DateTime( _
  2001, 4, 12, 22, 16, 49, 844)
System.DateTime dt =
 new System.DateTime(
 2001, 4, 12, 22, 16,
      49, 844);

New Features of both languages in 2005 version

VB.NET C#
Visual Basic 2005 has many new and improved language features — such as inheritance, interfaces, overriding, shared members, and overloading — that make it a powerful object-oriented programming language. As a Visual Basic developer, you can now create multithreaded, scalable applications using explicit multithreading. This language has following new features,

  1. Continue Statement, which immediately skips to the next iteration of a Do, For, or While loop.
  2. IsNot operator, which you can avoid using the Not and Is operators in an awkward order.
  3. 3. Using...End. Using statement block ensures disposal of a system resource when your code leaves the block for any reason.
    Public Sub setbigbold( _
        ByVal c As Control)
    Using nf As New _
      System.Drawing.Font("Arial",_
      12.0F, FontStyle.Bold)
      c.Font = nf
      c.Text = "This is" &_
      "12-point Arial bold"
    End Using
    End Sub
  4. Explicit Zero Lower Bound on an Array, Visual Basic now permits an array declaration to specify the lower bound (0) of each dimension along with the upper bound.
  5. Unsigned Types, Visual Basic now supports unsigned integer data types (UShort, UInteger, and ULong) as well as the signed type SByte.
  6. Operator Overloading, Visual Basic now allows you to define a standard operator (such as +, &, Not, or Mod) on a class or structure you have defined.
  7. Partial Types, to separate generated code from your authored code into separate source files.
  8. Visual Basic now supports type parameters on generic classes, structures, interfaces, procedures, and delegates. A corresponding type argument specifies at compilation time the data type of one of the elements in the generic type.
  9. Custom Events. You can declare custom events by using the Custom keyword as a modifier for the Event statement. In a custom event, you specify exactly what happens when code adds or removes an event handler to or from the event, or when code raises the event.
  10. Compiler Checking Options, The /nowarn and /warnaserror options provide more control over how warnings are handled. Each one of these compiler options now takes a list of warning IDs as an optional parameter, to specify to which warnings the option applies.
  11. There are eight new command-line compiler options:
    1. The /codepage option specifies which codepage to use when opening source files.
    2. The /doc option generates an XML documentation file based on comments within your code.
    3. The /errorreport option provides a convenient way to report a Visual Basic internal compiler error to Microsoft.
    4. The /filealign option specifies the size of sections in your output file.
    5. The /noconfig option causes the compiler to ignore the Vbc.rsp file.
    6. The /nostdlib option prevents the import of mscorlib.dll, which defines the entire System namespace.
    7. The /platform option specifies the processor to be targeted by the output file, in those situations where it is necessary to explicitly specify it.
    8. The /unify option suppresses warnings resulting from a mismatch between the versions of directly and indirectly referenced assemblies.
With the release of Visual Studio 2005, the C# language has been updated to version 2.0. This language has following new features:

  1. Generics types are added to the language to enable programmers to achieve a high level of code reuse and enhanced performance for collection classes. Generic types can differ only by arity. Parameters can also be forced to be specific types.
  2. Iterators make it easier to dictate how a for each loop will iterate over a collection’s contents.
    // Iterator Example
    public class NumChar
    {
    string[] saNum = {
      "One", "Two", "Three",
      "Four", "Five", "Six",
      "Seven", "Eight", "Nine",
      "Zero"};
    public
     System.Collections.IEnumerator
     GetEnumerator()
    {
    foreach (string num in saNum)
    yield return num;
    }
    }
    // Create an instance of
    // the collection class
    NumChar oNumChar = new NumChar();
    // Iterate through it with foreach
    foreach (string num in oNumChar)
    Console.WriteLine(num);
  3. Partial type definitions allow a single type, such as a class, to be split into multiple files. The Visual Studio designer uses this feature to separate its generated code from user code.
  4. Nullable types allow a variable to contain a value that is undefined.
  5. Anonymous Method is now possible to pass a block of code as a parameter. Anywhere a delegate is expected, a code block can be used instead: There is no need to define a new method.
    button1.Click +=
     delegate { MessageBox.Show(
     "Click!") };
  6. . The namespace alias qualifier (::) provides more control over accessing namespace members. The global :: alias allows to access the root namespace that may be hidden by an entity in your code.
  7. Static classes are a safe and convenient way of declaring a class containing static methods that cannot be instantiated. In C# v1.2 you would have defined the class constructor as private to prevent the class being instantiated.
  8. 8. There are eight new compiler options:
    1. /langversion option: Can be used to specify compatibility with a specific version of the language.
    2. /platform option: Enables you to target IPF (IA64 or Itanium) and AMD64 architectures.
    3. #pragma warning: Used to disable and enable individual warnings in code.
    4. /linkresource option: Contains additional options.
    5. /errorreport option: Can be used to report internal compiler errors to Microsoft over the Internet.
    6. /keycontainer and /keyfile: Support specifying cryptographic keys.

Conclusion

I think that this article will help you understand both language features and also you can choose a language based on your taste. I will update this article in future if there are any changes.

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One Response to “Complete Comparison for VB.NET and C#”

  1. I am really inspired along with your writing skills well with the layout in your weblog. Is this a paid subject or did you modify it yourself? Anyway stay up the excellent quality writing, it is rare to look a nice blog like this one these days..

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