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Imports System
Namespace Hello Class HelloWorld Overloads Shared SubMain(ByVal args() As String) Dim name As String = "VB.NET"
@H_404_75@'See if an argument was passed from the command line If args.Length = 1 Then name = args(0)
Console.WriteLine("Hello," & name & "!") End Sub End Class End Namespace |
using System;
namespace Hello { public class HelloWorld { public static voidMain(string[] args) { string name = "C#";
@H_404_75@// See if an argument was passed from the command line if (args.Length == 1) name = args[0];
Console.WriteLine("Hello," + name + "!"); } } } |
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@H_404_75@' Single line only @H_404_75@REMSingle line only @H_404_75@''' <summary>XML comments</summary> |
@H_404_75@// Single line /* Multiple line */ /// <summary>XML comments on single line</summary> /** <summary>XML comments on multiple lines</summary> */ |
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@H_404_75@Value Types Boolean Byte,SByte Char Short,UShort,Integer,UInteger,Long,ULong Single,Double Decimal Date @H_404_75@Reference Types Object String @H_404_75@Initializing Dim correct As Boolean = True Dim b As Byte = &H2A@H_404_75@'hex or &O52 for octal Dim person As Object = Nothing Dim name As String = "Dwight" Dim grade As Char = "B"c Dim today As Date = #12/31/2007 12:15:00 PM# Dim amount As Decimal = 35.99@ Dim gpa As Single = 2.9! Dim pi As Double = 3.14159265 Dim lTotal As Long = 123456L Dim sTotal As Short = 123S Dim usTotal As UShort = 123US Dim uiTotal As UInteger = 123UI Dim ulTotal As ULong = 123UL @H_404_75@Implicitly Typed Local Variables Dim s = "Hello!" Dim nums = New Integer() {1,2,3} Dim hero = New SuperHero With {.Name = "Batman"} @H_404_75@Type Information DimxAsInteger Console.WriteLine(x.GetType())@H_404_75@' Prints System.Int32 Console.WriteLine(GetType(Integer))@H_404_75@' Prints System.Int32 Console.WriteLine(TypeName(x))@H_404_75@' Prints Integer
Dim c as New Circle IfTypeOfcIsShape Then _ Console.WriteLine("c is a Shape") @H_404_75@Type Conversion / Casting Dim d As Single = 3.5 Dim i As Integer =CType(d,Integer)@H_404_75@' set to 4 (Banker's rounding) i =CInt(d)@H_404_75@' same result as CType i =Int(d)@H_404_75@' set to 3 (Int function truncates the decimal)
Dim o As Object = 2 i =DirectCast(o,Integer)@H_404_75@' Throws InvalidCastException if type cast fails
Dim s As New Shape Dim c As Circle =TryCast(s,Circle)@H_404_75@' Returns Nothing if type cast fails |
@H_404_75@Value Types bool byte,sbyte char short,ushort,int,uint,long,ulong float,double decimal DateTime@H_404_75@(not a built-in C# type) @H_404_75@Reference Types object string @H_404_75@Initializing bool correct = true; byte b = 0x2A;@H_404_75@// hex object person = null; string name = "Dwight"; char grade = 'B'; DateTime today = DateTime.Parse("12/31/2007 12:15:00"); decimal amount = 35.99m; float gpa = 2.9f; double pi = 3.14159265; long lTotal = 123456L; short sTotal = 123; ushort usTotal = 123; uint uiTotal = 123; ulong ulTotal = 123; @H_404_75@Implicitly Typed Local Variables var s = "Hello!"; var nums = new int[] { 1,3 }; var hero = new SuperHero() { Name = "Batman" }; @H_404_75@Type Information int x; Console.WriteLine(x.GetType());@H_404_75@// Prints System.Int32 Console.WriteLine(typeof(int));@H_404_75@// Prints System.Int32 Console.WriteLine(x.GetType().Name);@H_404_75@// prints Int32
Circle c = new Circle(); if (cisShape) Console.WriteLine("c is a Shape"); @H_404_75@Type Conversion / Casting float d = 3.5f; i =Convert.ToInt32(d);@H_404_75@// Set to 4 (rounds) int i =(int)d;@H_404_75@// set to 3 (truncates decimal)
object o = 2; int i = (int)o;@H_404_75@// Throws InvalidCastException if type cast fails
Shape s = new Shape(); Circle c = sasCircle;@H_404_75@// Returns null if type cast fails |
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ConstMAX_STUDENTSAsInteger = 25 @H_404_75@' Can set to a const or var; may be initialized in a constructor ReadOnlyMIN_DIAMETERAsSingle = 4.93 |
constint MAX_STUDENTS = 25; @H_404_75@// Can set to a const or var; may be initialized in a constructor readonlyfloat MIN_DIAMETER = 4.93f; |
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EnumAction Start [Stop]@H_404_75@' Stop is a reserved word Rewind Forward End Enum
EnumStatus Flunk = 50 Pass = 70 Excel = 90 End Enum
Dim a As Action = Action.Stop If a <> Action.Start Then _ Console.WriteLine(a.ToString & " is " & a)@H_404_75@' Prints "Stop is 1"
Console.WriteLine(Status.Pass)@H_404_75@' Prints 70 Console.WriteLine(Status.Pass.ToString())@H_404_75@' Prints Pass |
enumAction {Start,Stop,Rewind,Forward}; enumStatus {Flunk = 50,Pass = 70,Excel = 90};
Action a = Action.Stop; if (a != Action.Start) Console.WriteLine(a + " is " + (int) a);@H_404_75@// Prints "Stop is 1"
Console.WriteLine((int) Status.Pass);@H_404_75@// Prints 70 Console.WriteLine(Status.Pass);@H_404_75@// Prints Pass |
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@H_404_75@Comparison = < > <= >= <> @H_404_75@Arithmetic + - * / Mod /@H_404_75@(integer division) ^@H_404_75@(raise to a power) @H_404_75@Assignment = += -= *= /= /= ^= <<= >>= &= @H_404_75@Bitwise And Or Xor Not << >> @H_404_75@Logical AndAlso OrElse And Or Xor Not Note:AndAlso and OrElse perform short-circuit logical evaluations @H_404_75@String Concatenation & |
@H_404_75@Comparison == < > <= >= != @H_404_75@Arithmetic + - * / %@H_404_75@(mod) /@H_404_75@(integer division if both operands are ints) Math.Pow(x,y) @H_404_75@Assignment = += -= *= /= %= &= |= ^= <<= >>= ++ -- @H_404_75@Bitwise & | ^ ~ << >> @H_404_75@Logical && || & | ^ ! Note:&& and || perform short-circuit logical evaluations @H_404_75@String Concatenation + |
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@H_404_75@' Ternary/Conditional operator (Iff evaluates 2nd and 3rd expressions) greeting =If(age < 20,"What's up?","Hello") @H_404_75@' One line doesn't require "End If" Ifage < 20Thengreeting = "What's up?" Ifage < 20Thengreeting = "What's up?"Elsegreeting = "Hello" @H_404_75@' Use : to put two commands on same line Ifx <> 100 AndAlso y < 5Thenx *= 5:y *= 2 @H_404_75@' Preferred Ifx <> 100 AndAlso y < 5Then x *= 5 y *= 2 End If @H_404_75@' To break up any long single line use _ IfwhenYouHaveAReally < longLine And _ itNeedsToBeBrokenInto2 > LinesThen_ UseTheUnderscore(charToBreakItUp) @H_404_75@'Ifx > 5Then x *= y ElseIfx = 5 OrElse y Mod 2 = 0Then x += y ElseIfx < 10Then x -= y Else x /= y End If Select Casecolor@H_404_75@' Must be a primitive data type Case"pink","red" r += 1 Case"blue" b += 1 Case"green" g += 1 Case Else other += 1 End Select |
@H_404_75@// Ternary/Conditional operator greeting = age < 20?"What's up?":"Hello"; if(age < 20) greeting = "What's up?"; else greeting = "Hello"; @H_404_75@// Multiple statements must be enclosed in {} if(x != 100 && y < 5) { x *= 5; y *= 2; }
@H_404_75@No need for _ or : since ; is used to terminate each statement.
if(x > 5) x *= y; elseif (x == 5 || y % 2 == 0) x += y; elseif (x < 10) x -= y; else x /= y;
@H_404_75@// Every case must end with break or goto case switch(color) {// Must be integer or string case"pink": case"red": r++;break; case"blue": b++;break; case"green": g++;break; default: other++;break;@H_404_75@// break necessary on default } |
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@H_404_75@Pre-test Loops: |
Whilec < 10 c += 1 End While |
Do Untilc = 10 c += 1 Loop |
Do Whilec < 10 c += 1 Loop |
Forc = 2To10Step2 Console.WriteLine(c) Next |
@H_404_75@ Post-test Loops: |
Do c += 1 Loop Whilec < 10 |
Do c += 1 Loop Untilc = 10 |
@H_404_75@' Array or collection looping Dim names As String() = {"Fred","Sue","Barney"} For Eachs As StringInnames Console.WriteLine(s) Next @H_404_75@' Breaking out of loops Dim i As Integer = 0 While (True) If (i = 5) ThenExit While i += 1 End While @H_404_75@' Continue to next iteration For i = 0 To 4 If i < 4 ThenContinue For Console.WriteLine(i)@H_404_75@' Only prints 4 Next |
@H_404_75@Pre-test Loops: @H_404_75@// no "until" keyword while(c < 10) c++;
for(c = 2; c <= 10; c += 2) Console.WriteLine(c); @H_404_75@Post-test Loop:
do c++; while(c < 10); @H_404_75@// Array or collection looping string[] names = {"Fred","Barney"}; foreach(string sinnames) Console.WriteLine(s); @H_404_75@// Breaking out of loops int i = 0; while (true) { if (i == 5) break; i++; } @H_404_75@// Continue to next iteration for (i = 0; i < 5; i++) { if (i < 4) continue; Console.WriteLine(i);@H_404_75@// Only prints 4 } |
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Dim nums()As Integer = {1,3} For i As Integer = 0 To nums.Length - 1 Console.WriteLine(nums(i)) Next
@H_404_75@' 4 is the index of the last element,so it holds 5 elements Dim names(4) As String names(0) = "David" names(5) = "Bobby"@H_404_75@' Throws System.IndexOutOfRangeException
@H_404_75@' Resize the array,keeping the existing values (Preserve is optional) ReDim Preservenames(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 |
int[]nums = {1,3}; for (int i = 0; i < nums.Length; i++) Console.WriteLine(nums[i]);
@H_404_75@// 5 is the size of the array string[] names = new string[5]; names[0] = "David"; names[5] = "Bobby";@H_404_75@// Throws System.IndexOutOfRangeException
@H_404_75@// C# can't dynamically resize an array. Just copy into new array. string[] names2 = new string[7]; Array.Copy(names,names2,names.Length);@H_404_75@// or names.CopyTo(names2,0); float[,]twoD = new float[rows,cols]; twoD[2,0] = 4.5f; int[][]jagged = new int[3][] { new int[5],new int[2],new int[3] }; jagged[0][4] = 5; |
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@H_404_75@' Pass by value (in,default),reference (in/out),and reference (out) SubTestFunc(ByValx As Integer,ByRefy As Integer,ByRefz As Integer) x += 1 y += 1 z = 5 End Sub Dim a = 1,b = 1,c As Integer@H_404_75@' c set to zero by default TestFunc(a,b,c) Console.WriteLine("{0} {1} {2}",a,c)@H_404_75@' 1 2 5 @H_404_75@' Accept variable number of arguments FunctionSum(ByValParamArraynumsAsInteger()) As Integer Sum = 0 For Each i As Integer In nums Sum += i Next End Function@H_404_75@' Or use Return statement like C#
Dim total As Integer = Sum(4,3,1)@H_404_75@' returns 10 @H_404_75@' Optional parameters must be listed last and must have a default value SubSayHello(ByVal name As String,OptionalByVal prefix As String = "") Console.WriteLine("Greetings," & prefix & " " & name) End Sub
SayHello("Strangelove","Dr.") SayHello("Mom") |
@H_404_75@// Pass by value (in,and reference (out) void TestFunc(int x,refint y,outint z) { x++; y++; z = 5; } int a = 1,c;// c doesn't need initializing TestFunc(a,refb,outc); Console.WriteLine("{0} {1} {2}",c);@H_404_75@// 1 2 5 @H_404_75@// Accept variable number of arguments int Sum(paramsint[] nums) { int sum = 0; foreach (int i in nums) sum += i; return sum; } int total = Sum(4,1);// returns 10 @H_404_75@/* C# 4.0 supports optional parameters. PrevIoUs versions required function overloading. */ void SayHello(string name,string prefix = "") { Console.WriteLine("Greetings," + prefix + " " + name); } SayHello("Strangelove","Dr."); SayHello("Mom"); |
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@H_404_75@Special character constants (all also accessible from ControlChars class) vbCrLf,vbCr,vbLf,vbNewLine vbNullString vbTab vbBack vbFormFeed vbVerticalTab "" @H_404_75@' String concatenation (use & or +) Dim school As String = "Harding"&vbTab school = school & "University"@H_404_75@' school is "Harding (tab) University" @H_404_75@' Chars Dim letter AsChar= school.Chars(0)@H_404_75@' letter is H letter = "Z"c@H_404_75@' letter is Z letter = Convert.tochar(65)@H_404_75@' letter is A letter =Chr(65)@H_404_75@' same thing Dim word() As Char = school.tocharArray()@H_404_75@' word holds Harding @H_404_75@' No string literal operator Dim msg As String = "File is c:/temp/x.dat" @H_404_75@' String comparison Dim mascot As String = "Bisons" If (mascot = "Bisons") Then@H_404_75@' true If (mascot.Equals("Bisons")) Then@H_404_75@' true If (mascot.ToUpper().Equals("BISONS")) Then@H_404_75@' true If (mascot.CompareTo("Bisons") = 0) Then@H_404_75@' true @H_404_75@' String matching with Like - Regex is more powerful If ("John 3:16"Like"Jo[Hh]? #:*") Then@H_404_75@'true @H_404_75@' Substring s = mascot.Substring(2,3))@H_404_75@' s is "son" @H_404_75@' Replacement s = mascot.Replace("sons","nomial"))@H_404_75@' s is "Binomial" @H_404_75@' Split Dim names As String = "Michael,Dwight,Jim,Pam" Dim parts() As String = names.Split(",".tocharArray())@H_404_75@' One name in each slot @H_404_75@' Date to string Dim dt As New DateTime(1973,10,12) Dim s As String = "My birthday: " & dt.ToString("MMM dd,yyyy")@H_404_75@' Oct 12,1973 @H_404_75@' Integer to String Dim x As Integer = 2 Dim y As String = x.ToString()@H_404_75@' y is "2" @H_404_75@' String to Integer Dim x As Integer = Convert.ToInt32("-5")@H_404_75@' x is -5 @H_404_75@' Mutable string Dim buffer As New System.Text.StringBuilder("two ") buffer.Append("three ") buffer.Insert(0,"one ") buffer.Replace("two","TWO") Console.WriteLine(buffer)@H_404_75@' Prints "one TWO three" |
@H_404_75@Escape sequences /r@H_404_75@// carriage-return /n@H_404_75@// line-Feed /t@H_404_75@// tab //@H_404_75@// backslash /"@H_404_75@// quote @H_404_75@// String concatenation stringschool = "Harding/t"; school = school + "University";@H_404_75@// school is "Harding (tab) University" @H_404_75@// Chars charletter = school[0];@H_404_75@// letter is H letter = 'Z';@H_404_75@// letter is Z letter = Convert.tochar(65);@H_404_75@// letter is A letter =(char)65;@H_404_75@// same thing char[]word = school.tocharArray();@H_404_75@// word holds Harding @H_404_75@// String literal string msg =@"File is c:/temp/x.dat"; @H_404_75@// same as string msg = "File is c://temp//x.dat"; @H_404_75@// String comparison string mascot = "Bisons"; if (mascot == "Bisons")@H_404_75@// true if (mascot.Equals("Bisons"))@H_404_75@// true if (mascot.ToUpper().Equals("BISONS"))@H_404_75@// true if (mascot.CompareTo("Bisons") == 0)@H_404_75@// true @H_404_75@// String matching - No Like equivalent,use Regex @H_404_75@// Substring s = mascot.Substring(2,3))@H_404_75@// s is "son" @H_404_75@// Replacement s = mascot.Replace("sons","nomial"))@H_404_75@// s is "Binomial" @H_404_75@// Split string names = "Michael,Pam"; string[] parts = names.Split(",".tocharArray());@H_404_75@// One name in each slot @H_404_75@// Date to string DateTime dt = new DateTime(1973,12); string s = dt.ToString("MMM dd,yyyy");@H_404_75@// Oct 12,1973 @H_404_75@// int to string int x = 2; string y = x.ToString();@H_404_75@// y is "2" @H_404_75@// string to int int x = Convert.ToInt32("-5");@H_404_75@// x is -5 @H_404_75@// Mutable string System.Text.StringBuilderbuffer = new System.Text.StringBuilder("two "); buffer.Append("three "); buffer.Insert(0,"one "); buffer.Replace("two","TWO"); Console.WriteLine(buffer);@H_404_75@// Prints "one TWO three" |
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Imports System.Text.RegularExpressions @H_404_75@' Match a string pattern Dim r As NewRegex("j[aeIoU]h?. /d:*",RegexOptions.IgnoreCase Or _ RegexOptions.Compiled) If (r.Match("John 3:16").Success) Then@H_404_75@'true Console.WriteLine("Match") End If @H_404_75@' Find and remember all matching patterns Dim s As String = "My number is 305-1881,not 305-1818." Dim r As New Regex("(/d+-/d+)") Dim m AsMatch= r.Match(s)@H_404_75@' Matches 305-1881 and 305-1818 While m.Success Console.WriteLine("Found number: " & m.Groups(1).Value & " at position " _ & m.Groups(1).Index.ToString) m = m.NextMatch() End While @H_404_75@' Remeber multiple parts of matched pattern Dim r As New Regex("(/d/d):(/d/d) (am|pm)") Dim m As Match = r.Match("We left at 03:15 pm.") If m.Success Then Console.WriteLine("Hour: " & m.Groups(1).ToString)@H_404_75@' 03 Console.WriteLine("Min: " & m.Groups(2).ToString)@H_404_75@' 15 Console.WriteLine("Ending: " & m.Groups(3).ToString)@H_404_75@' pm End If @H_404_75@' Replace all occurrances of a pattern Dim r As New Regex("h/w+?d",RegexOptions.IgnoreCase) Dim s As String = r.Replace("I heard this was HARD!","easy")@H_404_75@' I easy this was easy! @H_404_75@' Replace matched patterns Dim s As String = Regex.Replace("123 < 456","(/d+) . (/d+)","$2 > $1")@H_404_75@' 456 > 123 @H_404_75@' Split a string based on a pattern Dim names As String = "Michael,Pam" Dim r As New Regex(",/s*") Dim parts() As String = r.Split(names)@H_404_75@' One name in each slot |
using System.Text.RegularExpressions; @H_404_75@// Match a string pattern Regexr = newRegex(@"j[aeIoU]h?. /d:*",RegexOptions.IgnoreCase | RegexOptions.Compiled); if (r.Match("John 3:16").Success)@H_404_75@// true Console.WriteLine("Match"); @H_404_75@// Find and remember all matching patterns string s = "My number is 305-1881,not 305-1818."; Regex r = new Regex("(//d+-//d+)"); @H_404_75@// Matches 305-1881 and 305-1818 for (Matchm = r.Match(s); m.Success; m = m.NextMatch()) Console.WriteLine("Found number: " + m.Groups[1] + " at position " + m.Groups[1].Index);
@H_404_75@// Remeber multiple parts of matched pattern Regex r = new Regex("@(/d/d):(/d/d) (am|pm)"); Match m = r.Match("We left at 03:15 pm."); if (m.Success) { Console.WriteLine("Hour: " + m.Groups[1]);@H_404_75@// 03 Console.WriteLine("Min: " + m.Groups[2]);@H_404_75@// 15 Console.WriteLine("Ending: " + m.Groups[3]);@H_404_75@// pm } @H_404_75@// Replace all occurrances of a pattern Regex r = new Regex("h//w+?d",RegexOptions.IgnoreCase); string s = r.Replace("I heard this was HARD!","easy"));@H_404_75@// I easy this was easy! @H_404_75@// Replace matched patterns string s = Regex.Replace("123 < 456",@"(/d+) . (/d+)","$2 > $1");@H_404_75@// 456 > 123 @H_404_75@// Split a string based on a pattern string names = "Michael,Pam"; Regex r = new Regex(@",/s*"); string[] parts = r.Split(names);@H_404_75@// One name in each slot |
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@H_404_75@' Throw an exception Dim ex As New Exception("Something is really wrong.") Throw ex @H_404_75@' Catch an exception Try y = 0 x = 10 / y Catchex As ExceptionWheny = 0@H_404_75@' Argument and When is optional Console.WriteLine(ex.Message) Finally Beep() End Try
@H_404_75@' Deprecated unstructured error handling OnErrorGoToMyErrorHandler ... MyErrorHandler: Console.WriteLine(Err.Description) |
@H_404_75@// Throw an exception Exception up = new Exception("Something is really wrong."); throwup;@H_404_75@// ha ha @H_404_75@// Catch an exception try{ y = 0; x = 10 / y; } catch(Exception ex) {@H_404_75@// Argument is optional,no "When" keyword Console.WriteLine(ex.Message); } finally{ Microsoft.VisualBasic.Interaction.Beep(); } |
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NamespaceHarding.Compsci.Graphics ... End Namespace @H_404_75@' or NamespaceHarding NamespaceCompsci NamespaceGraphics ... End Namespace End Namespace End Namespace ImportsHarding.Compsci.Graphics |
namespaceHarding.Compsci.Graphics { ... } @H_404_75@// or namespaceHarding { namespaceCompsci { namespaceGraphics { ... } } } usingHarding.Compsci.Graphics; |
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@H_404_75@Access Modifiers Public Private Friend Protected Protected Friend @H_404_75@Class Modifiers MustInherit NotInheritable @H_404_75@Method Modifiers MustOverride NotInheritable Shared Overridable @H_404_75@' All members are Shared Module @H_404_75@' Inheritance ClassFootballGame InheritsCompetition ... End Class @H_404_75@' Interface definition InterfaceIAlarmClock ... End Interface @H_404_75@// Extending an interface InterfaceIAlarmClock InheritsIClock ... End Interface @H_404_75@// Interface implementation ClassWristWatch ImplementsIAlarmClock,ITimer ... End Class |
@H_404_75@Access Modifiers public private internal protected protected internal @H_404_75@Class Modifiers abstract sealed static @H_404_75@Method Modifiers abstract sealed static virtual @H_404_75@No Module equivalent - just use static class @H_404_75@// Inheritance classFootballGame:Competition { ... } @H_404_75@ // Interface definition interfaceIAlarmClock { ... } @H_404_75@// Extending an interface interfaceIAlarmClock:IClock { ... } @H_404_75@ // Interface implementation classWristWatch:IAlarmClock,ITimer { ... } |
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ClassSuperHero Private powerLevel As Integer
Public SubNew() powerLevel = 0 End Sub
Public SubNew(ByVal powerLevel As Integer) Me.powerLevel = powerLevel End Sub
Shared SubNew() @H_404_75@' Shared constructor invoked before 1st instance is created End Sub
Protected Overrides SubFinalize() @H_404_75@' Destructor to free unmanaged resources MyBase.Finalize() End Sub End Class |
classSuperHero { private int powerLevel;
public SuperHero() { powerLevel = 0; }
public SuperHero(int powerLevel) { this.powerLevel = powerLevel; }
static SuperHero() { @H_404_75@// Static constructor invoked before 1st instance is created }
~SuperHero() { @H_404_75@// Destructor implicitly creates a Finalize method } } |
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Dim hero As SuperHero = New SuperHero @H_404_75@' or Dim hero As New SuperHero Withhero .Name = "SpamMan" .PowerLevel = 3 End With hero.Defend("Laura Jones") hero.Rest()@H_404_75@' Calling Shared method @H_404_75@' or SuperHero.Rest() Dim hero2 As SuperHero = hero@H_404_75@' Both reference the same object hero2.Name = "WormWoman" Console.WriteLine(hero.Name)@H_404_75@' Prints WormWoman hero =Nothing@H_404_75@' Free the object If heroIsNothingThen _ hero = New SuperHero Dim obj As Object = New SuperHero IfTypeOfobjIsSuperHero Then _ Console.WriteLine("Is a SuperHero object.") @H_404_75@' Mark object for quick disposal Usingreader As StreamReader = File.OpenText("test.txt") Dim line As String = reader.ReadLine() While Not line Is Nothing Console.WriteLine(line) line = reader.ReadLine() End While End Using |
SuperHero hero = new SuperHero(); @H_404_75@// No "With" construct hero.Name = "SpamMan"; hero.PowerLevel = 3; hero.Defend("Laura Jones"); SuperHero.Rest();@H_404_75@// Calling static method
SuperHero hero2 = hero;@H_404_75@// Both reference the same object hero2.Name = "WormWoman"; Console.WriteLine(hero.Name);@H_404_75@// Prints WormWoman hero =null;@H_404_75@// Free the object if (hero ==null) hero = new SuperHero(); Object obj = new SuperHero(); if (objisSuperHero) Console.WriteLine("Is a SuperHero object."); @H_404_75@// Mark object for quick disposal using(StreamReader reader = File.OpenText("test.txt")) { string line; while ((line = reader.ReadLine()) != null) Console.WriteLine(line); } |
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StructureStudentRecord Public name As String Public gpa As Single
Public Sub New(ByVal name As String,ByVal gpa As Single) Me.name = name Me.gpa = gpa End Sub End Structure Dim stu As StudentRecord = New StudentRecord("Bob",3.5) Dim stu2 As StudentRecord = stu
stu2.name = "Sue" Console.WriteLine(stu.name)@H_404_75@' Prints Bob Console.WriteLine(stu2.name)@H_404_75@' Prints Sue |
structStudentRecord { public string name; public float gpa;
public StudentRecord(string name,float gpa) { this.name = name; this.gpa = gpa; } } StudentRecord stu = new StudentRecord("Bob",3.5f); StudentRecord stu2 = stu;
stu2.name = "Sue"; Console.WriteLine(stu.name);@H_404_75@// Prints Bob Console.WriteLine(stu2.name);@H_404_75@// Prints Sue |
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@H_404_75@' Auto-implemented properties are new to VB10 PublicPropertyName As String PublicPropertySize As Integer = -1@H_404_75@' Default value,Get and Set both Public @H_404_75@' Traditional property implementation Private mName As String PublicPropertyName() As String Get Return mName End Get Set(ByVal value As String) mName = value End Set End Property @H_404_75@' Read-only property Private mPowerLevel As Integer PublicReadOnlyProperty PowerLevel() As Integer Get Return mPowerLevel End Get End Property @H_404_75@' Write-only property Private mHeight As Double PublicWriteOnlyProperty Height() As Double Set(ByVal value As Double) mHeight = If(value < 0,mHeight = 0,mHeight = value) End Set End Property |
@H_404_75@// Auto-implemented properties public string Name {get; set;} public int Size {get;protectedset;}@H_404_75@// Set default value in constructor
@H_404_75@// Traditional property implementation private string name; public string Name { get{ return name; } set{ name = value; } } @H_404_75@// Read-only property private int powerLevel; public int PowerLevel { get{ return powerLevel; } } @H_404_75@// Write-only property private double height; public double Height { set{ height = value < 0 ? 0 : value; } } |
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DelegateSub MsgArrivedEventHandler(ByVal message As String) EventMsgArrivedEvent As MsgArrivedEventHandler @H_404_75@' or to define an event which declares a delegate implicitly EventMsgArrivedEvent(ByVal message As String) AddHandlerMsgArrivedEvent,AddressOfMy_MsgArrivedCallback @H_404_75@' Won't throw an exception if obj is Nothing RaiseEventMsgArrivedEvent("Test message") RemoveHandlerMsgArrivedEvent,AddressOfMy_MsgArrivedCallback Imports System.Windows.Forms DimWithEventsMyButton As Button@H_404_75@' WithEvents can't be used on local variable MyButton = New Button Private Sub MyButton_Click(ByVal sender As System.Object,_ ByVal e As System.EventArgs)HandlesMyButton.Click MessageBox.Show(Me,"Button was clicked","Info",_ MessageBoxButtons.OK,MessageBoxIcon.Information) End Sub |
delegatevoid MsgArrivedEventHandler(string message); eventMsgArrivedEventHandler MsgArrivedEvent; @H_404_75@// Delegates must be used with events in C#
MsgArrivedEvent+=new MsgArrivedEventHandler(My_MsgArrivedEventCallback); MsgArrivedEvent("Test message");@H_404_75@// Throws exception if obj is null 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, MessageBoxButtons.OK,MessageBoxIcon.Information); } |
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@H_404_75@' Enforce accepted data type at compile-time Dim numbers As New List(Of Integer) numbers.Add(2) numbers.Add(4) DisplayList(Of Integer)(numbers) @H_404_75@' Subroutine can display any type of List Sub DisplayList(Of T)(ByVal list As List(Of T) For Each item AsTIn list Console.WriteLine(item) Next End Sub @H_404_75@' Class works on any data type Class SillyList(Of T) Private list(10) AsT Private rand As New Random
Public Sub Add(ByVal item AsT) list(rand.Next(10)) = item End Sub
Public Function GetItem() AsT Return list(rand.Next(10)) End Function End Class @H_404_75@' Limit T to only types that implement IComparable Function Maximum(Of T As IComparable)(ByVal ParamArray items AsT()) AsT Dim max AsT= items(0) For Each item AsTIn items If item.CompareTo(max) > 0 Then max = item Next Return max End Function |
@H_404_75@// Enforce accepted data type at compile-time List<int>numbers = new List<int>(); numbers.Add(2); numbers.Add(4); DisplayList<int>(numbers); @H_404_75@// Function can display any type of List void DisplayList<T>(List<T>list) { foreach (Titem in list) Console.WriteLine(item); } @H_404_75@// Class works on any data type class SillyList<T>{ privateT[] list = newT[10]; private Random rand = new Random();
public void Add(Titem) { list[rand.Next(10)] = item; }
publicTGetItem() { return list[rand.Next(10)]; } } @H_404_75@// Limit T to only types that implement IComparable TMaximum<T>(paramsT[] items)where T : IComparable<T>{ Tmax = items[0]; foreach (Titem in items) if (item.CompareTo(max) > 0) max = item; return max; } |
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Console.Write("What's your name? ") Dim name As String = Console.ReadLine() Console.Write("How old are you? ") Dim age As Integer = Val(Console.ReadLine()) Console.WriteLine("{0} is {1} years old.",name,age) @H_404_75@' or Console.WriteLine(name & " is " & age & " years old.")
Dim c As Integer c = Console.Read()@H_404_75@' Read single char Console.WriteLine(c)@H_404_75@' Prints 65 if user enters "A" |
Console.Write("What's your name? "); string name = Console.ReadLine(); Console.Write("How old are you? "); int age = Convert.ToInt32(Console.ReadLine()); Console.WriteLine("{0} is {1} years old.",age); @H_404_75@// or Console.WriteLine(name + " is " + age + " years old."); int c = Console.Read();@H_404_75@// Read single char Console.WriteLine(c);@H_404_75@// Prints 65 if user enters "A" |
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Imports System.IO @H_404_75@' Write out to text file Dim writer AsStreamWriter= File.CreateText("c:/myfile.txt") writer.WriteLine("Out to file.") writer.Close() @H_404_75@' Read all lines from text file Dim reader AsStreamReader= 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() @H_404_75@' Write out to binary file Dim str As String = "Text data" Dim num As Integer = 123 Dim binWriter As NewBinaryWriter(File.OpenWrite("c:/myfile.dat")) binWriter.Write(str) binWriter.Write(num) binWriter.Close() @H_404_75@' Read from binary file Dim binReader As NewBinaryReader(File.OpenRead("c:/myfile.dat")) str = binReader.ReadString() num = binReader.ReadInt32() binReader.Close() |
using System.IO; @H_404_75@// Write out to text file StreamWriterwriter = File.CreateText("c://myfile.txt"); writer.WriteLine("Out to file."); writer.Close(); @H_404_75@// Read all lines from text file StreamReaderreader = File.OpenText("c://myfile.txt"); string line = reader.ReadLine(); while (line != null) { Console.WriteLine(line); line = reader.ReadLine(); } reader.Close(); @H_404_75@// Write out to binary file string str = "Text data"; int num = 123; BinaryWriterbinWriter = new BinaryWriter(File.OpenWrite("c://myfile.dat")); binWriter.Write(str); binWriter.Write(num); binWriter.Close(); @H_404_75@// Read from binary file BinaryReaderbinReader = new BinaryReader(File.OpenRead("c://myfile.dat"));str = binReader.ReadString();num = binReader.ReadInt32();binReader.Close(); |