VB和C# 语法对比图 (代码实例)

lyx199285

由于接下来学习的是用C#，语法变化比较大..。我就找了个简单语法介绍的，希望大家能比较快接受..。
原来地址：http://www.studycs.com/html/512.html



C#和VB.net的语法相差还是比较大的. 可能你会C#,可能你会VB.
将它们俩放在一起对比一下你就会很快读懂,并掌握另一门语言.
相信下面这张图会对你帮助很大.

Comments
VB.NET 'Single line onlyRem Single line only	C# // Single line/* Multipleline *//// XML comments on single line/** XML comments on multiple lines */
Data Types
VB.NET 'Value TypesBooleanByteChar (example: "A")Short, Integer, LongSingle, DoubleDecimalDate 'Reference TypesObjectStringDim x As IntegerSystem.Console.WriteLine(x.GetType())System.Console.WriteLine(TypeName(x)) 'Type conversionDim d As Single = 3.5Dim i As Integer = CType (d, Integer)i = CInt (d)i = Int(d)	C# //Value Typesboolbyte, sbytechar (example: 'A')short, ushort, int, uint, long, ulongfloat, doubledecimalDateTime //Reference Typesobjectstringint x;Console.WriteLine(x.GetType())Console.WriteLine(typeof(int)) //Type conversionfloat d = 3.5;int i = (int) d
Constants
VB.NET Const MAX_AUTHORS As Integer = 25ReadOnly 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  ForwardEnd EnumEnum Status   Flunk = 50   Pass = 70   Excel = 90End EnumDim a As Action = Action.Stop If a <> Action.Start Then _'Prints "Stop is 1"    System.Console.WriteLine(a.ToString & " is " & a)'Prints 70System.Console.WriteLine(Status.Pass)'Prints PassSystem.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 70System.Console.WriteLine((int) Status.Pass); // Prints PassSystem.Console.WriteLine(Status.Pass);
Operators
VB.NET 'Comparison=  <  >  <=  >=  <> 'Arithmetic+  -  *  /Mod  (integer division)^  (raise to a power) 'Assignment=  +=  -=  *=  /=  =  ^=  <<=  >>=  &= 'BitwiseAnd  AndAlso  Or  OrElse  Not  <<  >> 'LogicalAnd  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 lineIf x <> 100 And y < 5 Then x *= 5 : y *= 2   'PreferredIf x <> 100 And y < 5 Then  x *= 5  y *= 2End 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 -= yElse  x /= yEnd If 'Must be a primitive data typeSelect Case color     Case "black", "red"    r += 1  Case "blue"    b += 1  Case "green"    g += 1  Case Else    other += 1End 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 stringswitch (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 += 1End While Do Until c = 10  c += 1Loop 'Post-test Loopo While c < 10  c += 1Loop For c = 2 To 10 Step 2  System.Console.WriteLine(c)Next 'Array or collection loopingDim 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 loopingstring[] 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 elementsDim names(4) As Stringnames(0) = "Steven"'Throws System.IndexOutOfRangeExceptionnames(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) = 4.5Dim 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);// 5 is the size of the arraystring[] names = new string[5];names[0] = "Steven";// Throws System.IndexOutOfRangeExceptionnames[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 = 5End Sub 'c set to zero by defaultDim a = 1, b = 1, c As IntegerTestFunc(a, b, c)System.Console.WriteLine("{0} {1} {2}", a, b, c) '1 2 5 'Accept variable number of argumentsFunction Sum(ByVal ParamArray nums As Integer()) As Integer  Sum = 0  For Each i As Integer In nums    Sum += i  NextEnd 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 valueSub SayHello(ByVal name As String,Optional ByVal prefix As String = "")  System.Console.WriteLine("Greetings, " & prefix& " " & name)End SubSayHello("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 initializingTestFunc(a, ref b, out c);System.Console.WriteLine("{0} {1} {2}", a, b, c); // 1 2 5 // Accept variable number of argumentsint 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 handlingOn 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 / yCatch 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 NamespaceEnd Namespace Imports ASPAlliance.DotNet.Community	C# namespace ASPAlliance.DotNet.Community {  ...} // or namespace ASPAlliance {  namespace DotNet {    namespace Community {      ...    }  }} using ASPAlliance.DotNet.Community;

lyx199285

1. 排版乱了，版主帮忙把帖子删了=。=

复制代码

Classes / Interfaces
VB.NET 'Accessibility keywordsPublicPrivateFriendProtectedProtected FriendShared 'InheritanceClass Articles  Inherits Authors  ...End Class 'Interface definitionInterface IArticle   ...End Interface 'Extending an interfaceInterface IArticle  Inherits IAuthor  ...End Interface 'Interface implementation</span>Class PublicationDate  Implements</strong> IArticle, IRating   ...End Class	C# //Accessibility keywordspublicprivateinternalprotectedprotected internalstatic //Inheritanceclass Articles: Authors {  ...} //Interface definitioninterface IArticle {  ...} //Extending an interfaceinterface IArticle: IAuthor {  ...} //Interface implementationclass 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 SubEnd 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 TopAuthorWith author  .Name = "Steven"  .AuthorRanking = 3End Withauthor.Rank("Scott")author.Demote() 'Calling Shared method'orTopAuthor.Rank() Dim author2 As TopAuthor = author 'Both refer to same objectauthor2.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 TopAuthorIf TypeOf obj Is TopAuthor Then _  System.Console.WriteLine("Is a TopAuthor object.")	C# TopAuthor author = new TopAuthor();//No "With" constructauthor.Name = "Steven";author.AuthorRanking = 3; author.Rank("Scott");TopAuthor.Demote() //Calling static method TopAuthor author2 = author //Both refer to same objectauthor2.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 SubEnd Structure Dim author As AuthorRecord = New AuthorRecord("Steven", 8.8)Dim author2 As AuthorRecord = authorauthor2.name = "Scott"System.Console.WriteLine(author.name) 'Prints StevenSystem.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 = authorauthor.name = "Scott";SystemConsole.WriteLine(author.name); //Prints StevenSystem.Console.WriteLine(author2.name); //Prints Scott
Properties
VB.NET Private _size As IntegerPublic 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 SetEnd 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 messageAs String) Event MsgArrivedEvent As MsgArrivedEventHandler 'or to define an event which declares a'delegate implicitlyEvent MsgArrivedEvent(ByVal message As String) AddHandler MsgArrivedEvent, AddressOf My_MsgArrivedCallback'Won't throw an exception if obj is NothingRaiseEvent MsgArrivedEvent("Test message")RemoveHandler MsgArrivedEvent, AddressOf My_MsgArrivedCallbackImports System.Windows.Forms 'WithEvents can't be used on local variableDim WithEvents MyButton As ButtonMyButton = 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 nullMsgArrivedEvent("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 constantsvbCrLf, vbCr, vbLf, vbNewLinevbNullStringvbTabvbBackvbFormFeedvbVerticalTab""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)'orSystem.Console.WriteLine(name & " is " & age & " years old.")Dim c As Integerc = System.Console.Read() 'Read single charSystem.Console.WriteLine(c) 'Prints 65 if user enters "A"	C# //Escape sequencesn, rt 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);//orSystem.Console.WriteLine(name + " is " +         age + " years old."); int c = System.Console.Read(); //Read single charSystem.Console.WriteLine(c); //Prints 65 if user enters "A"
File I/O
VB.NET Imports System.IO 'Write out to text fileDim writer As StreamWriter = File.CreateText  ("c:myfile.txt")writer.WriteLine("Out to file.")writer.Close() 'Read all lines from text fileDim 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 Whilereader.Close() 'Write out to binary fileDim str As String = "Text data"Dim num As Integer = 123Dim binWriter As New BinaryWriter(File.OpenWrite  ("c:myfile.dat"))binWriter.Write(str)binWriter.Write(num)binWriter.Close() 'Read from binary fileDim 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 fileStreamWriter writer = File.CreateText  ("c:myfile.txt");writer.WriteLine("Out to file.");writer.Close(); //Read all lines from text fileStreamReader 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 filestring str = "Text data";int num = 123;BinaryWriter binWriter = new BinaryWriter(File.OpenWrite  ("c:myfile.dat"));binWriter.Write(str);binWriter.Write(num);binWriter.Close(); //Read from binary fileBinaryReader binReader = new BinaryReader(File.OpenRead  ("c:myfile.dat"));str = binReader.ReadString();num = binReader.ReadInt32();binReader.Close();

faunus

lyx199285 发表于 2014-2-24 13:10
排版乱了，版主帮忙把帖子删了=。=

没关系，加个原址。
排版不是问题。

新发贴，还是要鼓励一下的。

microfaint

标记一下。补习一下英语接着看。

lyx199285

microfaint 发表于 2014-2-24 13:57
标记一下。补习一下英语接着看。

原帖的排版比较正常-。-  建议看原版的