Comments

	 

	VB.NET

	 

	'Single line only

	Rem Single line only

	 

	 C#

	// Single line

	/* Multiple

	line */

	/// XML comments on single line

	/** XML comments on multiple lines */

	 

	Data Types

	 

	VB.NET

	 

	'Value Types

	Boolean

	Byte

	Char (example: "A")

	Short, Integer, Long

	Single, Double

	Decimal

	Date

	

	'Reference Types

	Object

	String

	 

	Dim x As Integer

	System.Console.WriteLine(x.GetType())

	System.Console.WriteLine(TypeName(x))

	

	'Type conversion

	Dim d As Single = 3.5

	Dim i As Integer = CType (d, Integer)

	i = CInt (d)

	i = Int(d)

	 

	 C#

	 

	//Value Types

	bool

	byte, sbyte

	char (example: 'A')

	short, ushort, int, uint, long, ulong

	float, double

	decimal

	DateTime

	

	//Reference Types

	object

	string

	 

	int x;

	Console.WriteLine(x.GetType())

	Console.WriteLine(typeof(int))

	

	//Type conversion

	float d = 3.5;

	int i = (int) d

	 

	 

	Constants

	 

	VB.NET

	Const MAX_AUTHORS As Integer = 25

	ReadOnly MIN_RANK As Single = 5.00

	 C#

	const int MAX_AUTHORS = 25;

	readonly float MIN_RANKING = 5.00;

	 

	Enumerations

	 

	VB.NET

	Enum Action

	  Start

	  'Stop is a reserved word

	[Stop]

	  Rewind

	  Forward

	End Enum

	Enum Status

	   Flunk = 50

	   Pass = 70

	   Excel = 90

	End Enum

	Dim a As Action = Action.Stop 

	If a <> Action.Start Then _

	'Prints "Stop is 1" 

	   System.Console.WriteLine(a.ToString & " is " & a)

	'Prints 70

	System.Console.WriteLine(Status.Pass)

	'Prints Pass

	System.Console.WriteLine(Status.Pass.ToString())

	 C#

	enum Action {Start, Stop, Rewind, Forward};

	enum Status {Flunk = 50, Pass = 70, Excel = 90};

	 

	 

	 

	 

	 

	Action a = Action.Stop;

	if (a != Action.Start)

	//Prints "Stop is 1"

	  System.Console.WriteLine(a + " is " + (int) a);

	// Prints 70

	System.Console.WriteLine((int) Status.Pass); 

	// Prints Pass

	System.Console.WriteLine(Status.Pass);

	 

	Operators

	 

	VB.NET

	 

	'Comparison

	=  <  >  <=  >=  <>

	

	'Arithmetic

	+  -  *  /

	Mod

	  (integer division)

	^  (raise to a power)

	

	'Assignment

	=  +=  -=  *=  /=  =  ^=  <<=  >>=  &=

	

	'Bitwise

	And  AndAlso  Or  OrElse  Not  <<  >>

	

	'Logical

	And  AndAlso  Or  OrElse  Not

	

	'String Concatenation

	& 

	 

	 C#

	 

	//Comparison

	==  <  >  <=  >=  !=

	

	//Arithmetic

	+  -  *  /

	%  (mod)

	/  (integer division if both operands are ints)

	Math.Pow(x, y)

	

	//Assignment

	=  +=  -=  *=  /=   %=  &=  |=  ^=  <<=  >>=  ++  --

	

	//Bitwise

	&  |  ^   ~  <<  >>

	

	//Logical

	&&  ||   !

	

	//String Concatenation

	+

	 

	 

	Choices

	 

	VB.NET

	 

	greeting = IIf(age < 20, "What's up?", "Hello")

	

	'One line doesn't require "End If", no "Else"

	If language = "VB.NET" Then langType = "verbose"

	

	'Use: to put two commands on same line

	If x <> 100 And y < 5 Then x *= 5 : y *= 2  

	

	'Preferred

	If x <> 100 And y < 5 Then

	  x *= 5

	  y *= 2

	End If

	 

	

	'or to break up any long single command use _

	If henYouHaveAReally < longLine And _ 

	itNeedsToBeBrokenInto2   > Lines  Then _

	  UseTheUnderscore(charToBreakItUp)

	

	If x > 5 Then

	  x *= y 

	ElseIf x = 5 Then

	  x += y 

	ElseIf x < 10 Then

	  x -= y

	Else

	  x /= y

	End If

	

	'Must be a primitive data type

	Select Case color   

	  Case "black", "red"

	    r += 1

	  Case "blue"

	    b += 1

	  Case "green"

	    g += 1

	  Case Else

	    other += 1

	End Select

	 

	 C#

	 

	greeting = age < 20 ? "What's up?" : "Hello";

	 

	 

	 

	 

	 

	if (x != 100 && y < 5)

	{

	  // Multiple statements must be enclosed in {}

	  x *= 5;

	  y *= 2;

	}

	 

	 

	 

	

	if (x > 5) 

	  x *= y; 

	else if (x == 5) 

	  x += y; 

	else if (x < 10) 

	  x -= y; 

	else 

	  x /= y;

	 

	//Must be integer or string

	switch (color)

	{

	  case "black":

	  case "red":    r++;

	   break;

	  case "blue"

	   break;

	  case "green": g++;  

	   break;

	  default:    other++;

	   break;

	}

	 

	 

	Loops

	 

	VB.NET

	 

	'Pre-test Loops:

	While c < 10

	  c += 1

	End While Do Until c = 10

	  c += 1

	Loop

	

	'Post-test Loop:

	Do While c < 10

	  c += 1

	Loop

	

	For c = 2 To 10 Step 2

	  System.Console.WriteLine(c)

	Next

	 

	'Array or collection looping

	Dim names As String() = {"Steven", "SuOk", "Sarah"}

	For Each s As String In names

	  System.Console.WriteLine(s)

	Next

	 

	 C#

	//Pre-test Loops: while (i < 10)

	  i++;

	for (i = 2; i < = 10; i += 2)

	  System.Console.WriteLine(i);

	 

	 

	

	//Post-test Loop:

	do

	  i++;

	while (i < 10);

	 

	 

	 

	

	// Array or collection looping

	string[] names = {"Steven", "SuOk", "Sarah"};

	foreach (string s in names)

	  System.Console.WriteLine(s);

	 

	 

	Arrays

	 

	VB.NET

	 

	Dim nums() As Integer = {1, 2, 3}

	For i As Integer = 0 To nums.Length - 1 

	  Console.WriteLine(nums(i)) 

	Next

	'4 is the index of the last element, so it holds 5 elements

	Dim names(4) As String

	names(0) = "Steven"

	'Throws System.IndexOutOfRangeException

	names(5) = "Sarah"

	

	'Resize the array, keeping the existing

	'values (Preserve is optional)

	ReDim Preserve names(6)

	 

	 

	Dim twoD(rows-1, cols-1) As Single 

	twoD(2, 0) = 4.5

	

	Dim jagged()() As Integer = { _

	  New Integer(4) {}, New Integer(1) {}, New Integer(2) {} }

	jagged(0)(4) = 5

	 

	 C#

	 

	int[] nums = {1, 2, 3};

	for (int i = 0; i < nums.Length; i++)

	  Console.WriteLine(nums[i]);

	

	// 5 is the size of the array

	string[] names = new string[5];

	names[0] = "Steven";

	// Throws System.IndexOutOfRangeException

	names[5] = "Sarah"

	

	// C# can't dynamically resize an array.

	//Just copy into new array.

	string[] names2 = new string[7];

	// or names.CopyTo(names2, 0);

	Array.Copy(names, names2, names.Length);

	 

	float[,] twoD = new float[rows, cols];

	twoD[2,0] = 4.5;

	

	int[][] jagged = new int[3][] {

	  new int[5], new int[2], new int[3] };

	jagged[0][4] = 5;

	 

	 

	Functions

	 

	VB.NET

	 

	'Pass by value (in, default), reference

	'(in/out), and reference (out)

	Sub TestFunc(ByVal x As Integer, ByRef y As Integer,

	ByRef z As Integer)

	  x += 1

	  y += 1

	  z = 5

	End Sub

	

	'c set to zero by default

	Dim a = 1, b = 1, c As Integer

	TestFunc(a, b, c)

	System.Console.WriteLine("{0} {1} {2}", a, b, c) '1 2 5

	

	'Accept variable number of arguments

	Function Sum(ByVal ParamArray nums As Integer()) As Integer

	  Sum = 0

	  For Each i As Integer In nums

	    Sum += i

	  Next

	End Function 'Or use a Return statement like C#

	Dim total As Integer = Sum(4, 3, 2, 1) 'returns 10

	

	'Optional parameters must be listed last

	'and must have a default value

	Sub SayHello(ByVal name As String,

	Optional ByVal prefix As String = "")

	  System.Console.WriteLine("Greetings, " & prefix

	& " " & name)

	End Sub

	

	SayHello("Steven", "Dr.")

	SayHello("SuOk")

	

	 

	 C#

	// Pass by value (in, default), reference

	//(in/out), and reference (out)

	void TestFunc(int x, ref int y, out int z) {

	  x++;

	  y++;

	  z = 5;

	}

	 

	

	int a = 1, b = 1, c; // c doesn't need initializing

	TestFunc(a, ref b, out c);

	System.Console.WriteLine("{0} {1} {2}", a, b, c); // 1 2 5

	

	// Accept variable number of arguments

	int Sum(params int[] nums) {

	  int sum = 0;

	  foreach (int i in nums)

	    sum += i;

	  return sum;

	}

	

	int total = Sum(4, 3, 2, 1); // returns 10

	

	/* C# doesn't support optional arguments/parameters.

	Just create two different versions of the same function. */

	void SayHello(string name, string prefix) {

	  System.Console.WriteLine("Greetings, "  + prefix + " " + name);

	}

	void SayHello(string name) {

	  SayHello(name, "");

	}

	 

	 

	Exception Handling

	 

	VB.NET

	 

	'Deprecated unstructured error handling

	On Error GoTo MyErrorHandler

	...

	MyErrorHandler: System.Console.WriteLine(Err.Description)

	Dim ex As New Exception("Something has really gone wrong.")

	Throw ex

	

	Try

	  y = 0

	  x = 10 / y

	Catch ex As Exception When y = 0 'Argument and When is optional

	  System.Console.WriteLine(ex.Message) 

	Finally

	  DoSomething() 

	End Try

	 

	 C#

	 

	 

	 

	Exception up = new Exception("Something is really wrong."); 

	throw up; // ha ha

	

	try{

	  y = 0;

	  x = 10 / y;

	}

	catch (Exception ex) { //Argument is optional, no "When" keyword

	  Console.WriteLine(ex.Message);

	}

	finally{

	  // Do something

	}

	 

	 

	Namespaces

	 

	VB.NET

	 

	Namespace ASPAlliance.DotNet.Community

	  ...

	End Namespace

	

	'or

	

	Namespace ASPAlliance 

	  Namespace DotNet

	    Namespace Community

	      ...

	    End Namespace

	  End Namespace

	End Namespace

	

	Imports ASPAlliance.DotNet.Community

	 

	 C#

	 

	namespace ASPAlliance.DotNet.Community {

	  ...

	}

	

	// or

	

	namespace ASPAlliance {

	  namespace DotNet {

	    namespace Community {

	      ...

	    }

	  }

	}

	

	using ASPAlliance.DotNet.Community;

	 

	 

	Classes / Interfaces

	 

	VB.NET

	 

	'Accessibility keywords

	Public

	Private

	Friend

	Protected

	Protected Friend

	Shared

	

	'Inheritance

	Class Articles

	  Inherits Authors

	  ...

	End Class

	

	'Interface definition

	Interface IArticle 

	  ...

	End Interface

	

	'Extending an interface

	Interface IArticle

	  Inherits IAuthor

	  ...

	End Interface

	

	'Interface implementation</span>

	Class PublicationDate

	  Implements</strong> IArticle, IRating

	   ...

	End Class

	 

	 C#

	 

	//Accessibility keywords

	public

	private

	internal

	protected

	protected internal

	static

	

	//Inheritance

	class Articles: Authors {

	  ...

	}

	 

	//Interface definition

	interface IArticle {

	  ...

	}

	

	//Extending an interface

	interface IArticle: IAuthor {

	  ...

	}

	 

	//Interface implementation

	class PublicationDate: IArticle, IRating {

	   ...

	}

	 

	 

	Constructors / Destructors

	 

	VB.NET

	Class TopAuthor

	  Private _topAuthor As Integer

	  Public Sub New()

	    _topAuthor = 0

	  End Sub

	  Public Sub New(ByVal topAuthor As Integer)

	    Me._topAuthor = topAuthor

	  End Sub

	  Protected Overrides Sub Finalize()

	   'Desctructor code to free unmanaged resources

	    MyBase.Finalize() 

	  End Sub

	End Class

	 C#

	 

	class TopAuthor {

	  private int _topAuthor;

	  public TopAuthor() {

	     _topAuthor = 0;

	  }

	  public TopAuthor(int topAuthor) {

	    this._topAuthor= topAuthor

	  }

	  ~TopAuthor() {

	    // Destructor code to free unmanaged resources.

	    // Implicitly creates a Finalize method

	  }

	}

	 

	 

	Objects

	 

	VB.NET

	 

	Dim author As TopAuthor = New TopAuthor

	With author

	  .Name = "Steven"

	  .AuthorRanking = 3

	End With

	author.Rank("Scott")

	author.Demote() 'Calling Shared method

	'or

	TopAuthor.Rank()

	

	Dim author2 As TopAuthor = author 'Both refer to same object

	author2.Name = "Joe"

	System.Console.WriteLine(author2.Name) 'Prints Joe

	

	author = Nothing 'Free the object

	

	If author Is Nothing Then _

	  author = New TopAuthor

	

	Dim obj As Object = New TopAuthor

	If TypeOf obj Is TopAuthor Then _

	  System.Console.WriteLine("Is a TopAuthor object.")

	 

	 C#

	 

	TopAuthor author = new TopAuthor();

	//No "With" construct

	author.Name = "Steven";

	author.AuthorRanking = 3;

	

	author.Rank("Scott");

	TopAuthor.Demote() //Calling static method

	 

	

	TopAuthor author2 = author //Both refer to same object

	author2.Name = "Joe";

	System.Console.WriteLine(author2.Name) //Prints Joe

	

	author = null //Free the object

	

	if (author == null)

	  author = new TopAuthor();

	

	Object obj = new TopAuthor(); 

	if (obj is TopAuthor)

	  SystConsole.WriteLine("Is a TopAuthor object.");

	 

	 

	Structs

	 

	VB.NET

	 

	Structure AuthorRecord

	  Public name As String

	  Public rank As Single

	  Public Sub New(ByVal name As String, ByVal rank As Single) 

	    Me.name = name

	    Me.rank = rank

	  End Sub

	End Structure

	

	Dim author As AuthorRecord = New AuthorRecord("Steven", 8.8)

	Dim author2 As AuthorRecord = author

	author2.name = "Scott"

	System.Console.WriteLine(author.name) 'Prints Steven

	System.Console.WriteLine(author2.name) 'Prints Scott

	 

	 C#

	struct AuthorRecord {

	  public string name;

	  public float rank;

	  public AuthorRecord(string name, float rank) {

	    this.name = name;

	    this.rank = rank;

	  }

	}

	 

	AuthorRecord author = new AuthorRecord("Steven", 8.8);

	AuthorRecord author2 = author

	author.name = "Scott";

	SystemConsole.WriteLine(author.name); //Prints Steven

	System.Console.WriteLine(author2.name); //Prints Scott

	 

	 

	Properties

	 

	VB.NET

	 

	Private _size As Integer

	Public Property Size() As Integer

	  Get

	    Return _size

	  End Get

	  Set (ByVal Value As Integer)

	    If Value < 0 Then

	      _size = 0

	    Else

	      _size = Value

	    End If

	  End Set

	End Property

	

	foo.Size += 1

	 

	 C#

	private int _size;

	public int Size {

	  get {

	    return _size;

	  }

	  set {

	    if (value < 0)

	      _size = 0;

	    else

	      _size = value;

	  }

	}

	 

	foo.Size++;

	 

	 

	Delegates / Events

	 

	VB.NET

	 

	Delegate Sub MsgArrivedEventHandler(ByVal message

	As String)

	

	Event MsgArrivedEvent As MsgArrivedEventHandler

	

	'or to define an event which declares a

	'delegate implicitly

	Event MsgArrivedEvent(ByVal message As String)

	

	AddHandler MsgArrivedEvent, AddressOf My_MsgArrivedCallback

	'Won't throw an exception if obj is Nothing

	RaiseEvent MsgArrivedEvent("Test message")

	RemoveHandler MsgArrivedEvent, AddressOf My_MsgArrivedCallback

	 

	Imports System.Windows.Forms

	

	'WithEvents can't be used on local variable

	Dim WithEvents MyButton As Button

	MyButton = New Button

	

	Private Sub MyButton_Click(ByVal sender As System.Object, _

	  ByVal e As System.EventArgs) Handles MyButton.Click

	  MessageBox.Show(Me, "Button was clicked", "Info", _

	    MessageBoxButtons.OK, MessageBoxIcon.Information)

	End Sub

	 

	 C#

	 

	delegate void MsgArrivedEventHandler(string message);

	

	event MsgArrivedEventHandler MsgArrivedEvent;

	

	//Delegates must be used with events in C#

	

	MsgArrivedEvent += new MsgArrivedEventHandler

	  (My_MsgArrivedEventCallback);

	//Throws exception if obj is null

	MsgArrivedEvent("Test message");

	MsgArrivedEvent -= new MsgArrivedEventHandler

	  (My_MsgArrivedEventCallback);

	 

	using System.Windows.Forms;

	

	Button MyButton = new Button();

	MyButton.Click += new System.EventHandler(MyButton_Click);

	

	private void MyButton_Click(object sender,    System.EventArgs e) {

	  MessageBox.Show(this, "Button was clicked", "Info",

	    MessageBoxButtons.OK, MessageBoxIcon.Information);

	}

	 

	 

	Console I/O

	 

	VB.NET

	 

	'Special character constants

	vbCrLf, vbCr, vbLf, vbNewLine

	vbNullString

	vbTab

	vbBack

	vbFormFeed

	vbVerticalTab

	""

	Chr(65) 'Returns 'A'

	

	System.Console.Write("What's your name? ")

	Dim name As String = System.Console.ReadLine()

	System.Console.Write("How old are you? ")

	Dim age As Integer = Val(System.Console.ReadLine())

	System.Console.WriteLine("{0} is {1} years old.", name, age)

	'or

	System.Console.WriteLine(name & " is " & age & " years old.")

	Dim c As Integer

	c = System.Console.Read() 'Read single char

	System.Console.WriteLine(c) 'Prints 65 if user enters "A"

	 

	 C#

	 

	//Escape sequences

	n, r

	t

	 

	

	Convert.ToChar(65) //Returns 'A' - equivalent to Chr(num) in VB

	// or

	(char) 65

	

	System.Console.Write("What's your name? ");

	string name = SYstem.Console.ReadLine();

	System.Console.Write("How old are you? ");

	int age = Convert.ToInt32(System.Console.ReadLine());

	System.Console.WriteLine("{0} is {1} years old.",  name, age);

	//or

	System.Console.WriteLine(name + " is " +  age + " years old.");

	

	int c = System.Console.Read(); //Read single char

	System.Console.WriteLine(c); //Prints 65 if user enters "A"

	 

	 

	File I/O

	 

	VB.NET

	 

	Imports System.IO

	

	'Write out to text file

	Dim writer As StreamWriter = File.CreateText

	  ("c:myfile.txt")

	writer.WriteLine("Out to file.")

	writer.Close()

	

	'Read all lines from text file

	Dim reader As StreamReader = File.OpenText

	  ("c:myfile.txt")

	Dim line As String = reader.ReadLine()

	While Not line Is Nothing

	  Console.WriteLine(line)

	  line = reader.ReadLine()

	End While

	reader.Close()

	

	'Write out to binary file

	Dim str As String = "Text data"

	Dim num As Integer = 123

	Dim binWriter As New BinaryWriter(File.OpenWrite

	  ("c:myfile.dat"))

	binWriter.Write(str)

	binWriter.Write(num)

	binWriter.Close()

	

	'Read from binary file

	Dim binReader As New BinaryReader(File.OpenRead

	  ("c:myfile.dat"))

	str = binReader.ReadString()

	num = binReader.ReadInt32()

	binReader.Close()

	 

	 C#