C#和VB.Net的語法相差還是比較大的. 可能你會C#,可能你會VB.
將它們倆放在一起對比一下你就會很快讀懂,並掌握另一門語言.
相信下面這張圖會對你幫助很大.
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 Loop:Do 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[i]);// 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;
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();
