This work is licensed under a Create Common License
[ Download Word Version or PDF Version ]
| |
Comments | |
| 'Single line only Rem Single line only | C# // Single line /* Multiple line */ /// XML comments on single line /** XML comments on multiple lines */ |
Program Structure | |
| Imports System Namespace MyNameSpace Class HelloWorld 'Entry point which delegates to C-style main Private Function Public Overloads Shared Sub Main() Main(System.Environment.GetCommandLineArgs()) End Sub
Overloads Shared Sub Main(args() As String) System.Console.WriteLine("Hello World") End Sub 'Main End Class 'HelloWorld End Namespace 'MyNameSpace | C# using System Namespace MyNameSpace { class HelloWorld { static void Main(string[] args) { System.Console.WriteLine("Hello World") } } }
|
Data Types | |
| '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 | |
| 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 | |
| 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())
Enum Weekdays Saturday Sunday Monday Tuesday Wednesday Thursday Friday End Enum 'Weekdays | 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);
enum Weekdays { Saturday, Sunday, Monday, Tuesday, Wednesday, Thursday, Friday }
|
| Operators | |
| '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 | |
| 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 | |
| '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 | |
| 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) {}, NewInteger(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 | |
| 'Pass by value (in, default), reference '(in/out), and reference (out) Sub TestFunc(ByVal x As Integer, ByRef y AsInteger, 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()) AsInteger 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 | |
| Class Withfinally Public Shared Sub Main() Try Dim x As Integer = 5 Dim y As Integer = 0 Dim z As Integer = x / y Console.WriteLine(z) Catch e As DivideByZeroException System.Console.WriteLine("Error occurred") Finally System.Console.WriteLine("Thank you") End Try End Sub 'Main End Class 'Withfinally | C# class Withfinally { public static void Main() { try { int x = 5; int y = 0; int z = x/y; Console.WriteLine(z); } catch(DivideByZeroException e) { System.Console.WriteLine("Error occurred"); } finally { System.Console.WriteLine("Thank you"); } } } |
| Namespaces | |
| 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 | |
| 'Accessibility keywords Public Private Friend Protected Protected Friend Shared
'Inheritance Class Articles Inherits Authors ... End Class
Imports System
Interface IArticle Sub Show() End Interface 'IArticle _
Class IAuthor Implements IArticle
Public Sub Show() System.Console.WriteLine("Show() method Implemented") End Sub 'Show
'Entry point which delegates to C-style main Private Function Public Overloads Shared Sub Main() Main(System.Environment.GetCommandLineArgs()) End Sub
Overloads Public Shared Sub Main(args() AsString) Dim author As New IAuthor() author.Show() End Sub 'Main End Class 'IAuthor | C# //Accessibility keywords public private internal protected protected internal static
//Inheritance class Articles: Authors { ... }
using System;
interface IArticle { void Show(); }
class IAuthor:IArticle { public void Show() { System.Console.WriteLine("Show() method Implemented"); }
public static void Main(string[] args) { IAuthor author = new IAuthor(); author.Show(); } }
|
| Constructors / Destructors | |
| 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 | |
| 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 | |
| Structure AuthorRecord Public name As String Public rank As Single
Public Sub New(ByVal name As String, ByVal rankAs Single) Me.name = name Me.rank = rank End Sub End Structure
Dim author As AuthorRecord = NewAuthorRecord("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, floatrank) { this.name = name; this.rank = rank; } }
AuthorRecord author = newAuthorRecord("Steven", 8.8); AuthorRecord author2 = author
author.name = "Scott"; SystemConsole.WriteLine(author.name);//Prints Steven System.Console.WriteLine(author2.name);//Prints Scott
|
| Properties | |
| 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
Imports System
Class [Date]
Public Property Day() As Integer Get Return day End Get Set day = value End Set End Property Private day As Integer
Public Property Month() As Integer Get Return month End Get Set month = value End Set End Property Private month As Integer
Public Property Year() As Integer Get Return year End Get Set year = value End Set End Property Private year As Integer
Public Function IsLeapYear(year As Integer) AsBoolean Return(If year Mod 4 = 0 Then True ElseFalse) End Function 'IsLeapYear
Public Sub SetDate(day As Integer, month AsInteger, year As Integer) Me.day = day Me.month = month Me.year = year End Sub 'SetDate End Class '[Date] | C# private int _size;
public int Size { get { return _size; } set { if (value < 0) _size = 0; else _size = value; } }
foo.Size++;
using System; class Date { public int Day{ get { return day; } set { day = value; } } int day;
public int Month{ get { return month; } set { month = value; } } int month;
public int Year{ get { return year; } set { year = value; } } int year;
public bool IsLeapYear(int year) { return year%4== 0 ? true: false; } public void SetDate (int day, intmonth, int year) { this.day = day; this.month = month; this.year = year; } } |
Delegates / Events | |
| 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, AddressOfMy_MsgArrivedCallback 'Won't throw an exception if obj is Nothing RaiseEvent MsgArrivedEvent("Test message") RemoveHandler MsgArrivedEvent, AddressOfMy_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 AsSystem.Object, _ ByVal e As System.EventArgs) HandlesMyButton.Click MessageBox.Show(Me, "Button was clicked", "Info", _ MessageBoxButtons.OK, MessageBoxIcon.Information) End Sub | C# delegate void MsgArrivedEventHandler(stringmessage);
event MsgArrivedEventHandler MsgArrivedEvent;
//Delegates must be used with events in C#
MsgArrivedEvent += newMsgArrivedEventHandler (My_MsgArrivedEventCallback); //Throws exception if obj is null MsgArrivedEvent("Test message"); MsgArrivedEvent -= newMsgArrivedEventHandler (My_MsgArrivedEventCallback);
using System.Windows.Forms;
Button MyButton = new Button(); MyButton.Click += newSystem.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 | |
| '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 | |
| 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# using System.IO;
//Write out to text file StreamWriter writer = File.CreateText ("c:\\myfile.txt"); writer.WriteLine("Out to file."); writer.Close();
//Read all lines from text file StreamReader reader = File.OpenText ("c:\\myfile.txt"); string line = reader.ReadLine(); while (line != null) { Console.WriteLine(line); line = reader.ReadLine(); } reader.Close();
//Write out to binary file string str = "Text data"; int num = 123; BinaryWriter binWriter = newBinaryWriter(File.OpenWrite ("c:\\myfile.dat")); binWriter.Write(str); binWriter.Write(num); binWriter.Close();
//Read from binary file BinaryReader binReader = newBinaryReader(File.OpenRead ("c:\\myfile.dat")); str = binReader.ReadString(); num = binReader.ReadInt32(); binReader.Close(); |
