VB C# 语法对比图 (代码实例)

fieldmax

该贴手工整理，未经过严格校验，有可能出现语句字符不完整或随意断句等错误

VB C# 语法对比图 (代码实例)

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.

注释
VB.NET 'Single line only Rem Single line only 复制代码	C# // Single line /* Multiple line */ /// XML comments on single line /** XML comments on multiple lines */ 复制代码
数据类型
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) 复制代码	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 复制代码
常量和变量
VB.NET Const MAX_AUTHORS As Integer = 25 ReadOnly MIN_RANK As Single = 5.00 复制代码	C# const int MAX_AUTHORS = 25; readonly float MIN_RANKING = 5.00; 复制代码
枚举
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()) 复制代码	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); 复制代码
运算
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 & 复制代码	C# //Comparison ==  <  >  <=  >=  != //Arithmetic +  -  *  / %  (mod) /  (integer division if both operands are ints) Math.Pow(x, y) //Assignment =  +=  -=  *=  /=   %=  &=  |=  ^=  <<=  >>=  ++  -- //Bitwise &  |  ^   ~  <<  >> //Logical &&  ||   ! //String Concatenation + 复制代码
条件
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 复制代码	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; } 复制代码
循环
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 复制代码	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); 复制代码
数组
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 复制代码	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; 复制代码
函数
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") 复制代码	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, ""); } 复制代码
错误处理
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 复制代码	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 } 复制代码
命名空间
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 复制代码	C# namespace ASPAlliance.DotNet.Community {   ... } // or namespace ASPAlliance {   namespace DotNet {     namespace Community {       ...     }   } } using ASPAlliance.DotNet.Community; 复制代码
类 / 接口
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 复制代码	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 {    ... } 复制代码
创建 / 销毁
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 复制代码	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   } } 复制代码
对象
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.") 复制代码	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."); 复制代码
结构
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 复制代码	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 复制代码
属性
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 复制代码	C# private int _size; public int Size {   get {     return _size;   }   set {     if (value < 0)       _size = 0;     else       _size = value;   } } foo.Size++; 复制代码
委派 / 事件
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 复制代码	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); } 复制代码
控制台 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" 复制代码	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" 复制代码
文件 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() 复制代码	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 = new BinaryWriter(File.OpenWrite   ("c:myfile.dat")); binWriter.Write(str); binWriter.Write(num); binWriter.Close(); //Read from binary file BinaryReader binReader = new BinaryReader(File.OpenRead   ("c:myfile.dat")); str = binReader.ReadString(); num = binReader.ReadInt32(); binReader.Close(); 复制代码

最后更新 (2005-03-02 19:10 )

fieldmax

我觉得这贴很有价值，为什么没人看呢！为了看起来更直观，帖子改到下半夜2点左右

fieldmax

再顶下，我觉得这篇文章有价值

jztgwq

学 VB.NET好了，还是学c#好了