Murray Gordon

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.)
• Catch ... When ... 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.

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