VB与C#的区别（转载）(2)

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VB与C#的区别（转载）(2)

Dim buffer As New System.Text.StringBuilder("two ")
            buffer.Append("three ")
            buffer.Insert(0, "one ")
            buffer.Replace("two", "TWO")
            Console.WriteLine(buffer)         ' Prints "one TWO three"

Escape sequences
            "n, "r
            "t
            ""
            ""

// String concatenation
string school = "Harding"t";
school = school + "University"; // school is "Harding (tab) University"

// Chars
char letter = school[0];            // letter is H
            letter = Convert.ToChar(65);     // letter is A
            letter = (char)65;                    // same thing
char[] word = school.ToCharArray();   // word holds Harding

// String literal
string msg = @"File is c:"temp"x.dat";
// same as
string msg = "File is c:""temp""x.dat";

// String comparison
            string mascot = "Bisons";
            if (mascot == "Bisons")    // true
            if (mascot.Equals("Bisons"))   // true
            if (mascot.ToUpper().Equals("BISONS"))   // true
            if (mascot.CompareTo("Bisons") == 0)    // true

Console.WriteLine(mascot.Substring(2, 3)); // Prints "son"

// String matching
// No Like equivalent - use regular expressions

using System.Text.RegularExpressions;
Regex r = new Regex(@"Jo[hH]. "d:*");
if (r.Match("John 3:16").Success) // true

// My birthday: Oct 12, 1973
DateTime dt = new DateTime(1973, 10, 12);
string s = "My birthday: " + dt.ToString("MMM dd, yyyy");

// Mutable string
            System.Text.StringBuilder buffer = new System.Text.StringBuilder("two ");
            buffer.Append("three ");
            buffer.Insert(0, "one ");
            buffer.Replace("two", "TWO");
            Console.WriteLine(buffer);     // Prints "one TWO three"

VB.NET

Exception Handling

' Throw an exception
Dim ex As New Exception("Something is really wrong.")
Throw ex

' Catch an exception
Try
              y = 0
              x = 10 / y
Catch ex As Exception When y = 0 ' Argument and When is optional
              Console.WriteLine(ex.Message)
Finally
              Beep()
End Try

' Deprecated unstructured error handling
On Error GoTo MyErrorHandler
...
MyErrorHandler: Console.WriteLine(Err.Description)

// Throw an exception
Exception up = new Exception("Something is really wrong.");
throw up; // ha ha

// Catch an exception
try {
              y = 0;
              x = 10 / y;
            }
catch (Exception ex) {   // Argument is optional, no "When" keyword
              Console.WriteLine(ex.Message);
            }
finally {
              // Requires reference to the Microsoft.VisualBasic.dll
// assembly (pre .NET Framework v2.0)
              Microsoft.VisualBasic.Interaction.Beep();
            }

VB.NET

Namespaces

Namespace Harding.Compsci.Graphics
...
End Namespace

' or

Namespace Harding
              Namespace Compsci
                Namespace Graphics
                  ...
                End Namespace
              End Namespace
End Namespace

Imports Harding.Compsci.Graphics

namespace Harding.Compsci.Graphics {
...
}

// or

namespace Harding {
              namespace Compsci {
                namespace Graphics {
                  ...
                }
              }
            }

using Harding.Compsci.Graphics;

VB.NET

Classes / Interfaces

Accessibility keywords
            Public
            Private
            Friend
            Protected
            Protected Friend
            Shared

' Inheritance
Class FootballGame
Inherits Competition
...
End Class

' Interface definition
Interface IAlarmClock
...
End Interface

// Extending an interface
Interface IAlarmClock
Inherits IClock
...
End Interface

// Interface implementation
Class WristWatch
Implements IAlarmClock, ITimer
...
End Class

Accessibility keywords
            public
            private
            internal
            protected
            protected internal
            static

// Inheritance
class FootballGame : Competition {
...
}

// Interface definition
interface IAlarmClock {
...
}

// Extending an interface
interface IAlarmClock : IClock {
...
}

// Interface implementation
class WristWatch : IAlarmClock, ITimer {
...
}

VB.NET

Constructors / Destructors

Class SuperHero
              Private _powerLevel As Integer

              Public Sub New()
                _powerLevel = 0
              End Sub

              Public Sub New(ByVal powerLevel As Integer)
                Me._powerLevel = powerLevel
              End Sub

              Protected Overrides Sub Finalize()
               ' Desctructor code to free unmanaged resources
                MyBase.Finalize()
              End Sub
End Class

class SuperHero {
              private int _powerLevel;

              public SuperHero() {
                 _powerLevel = 0;
              }

              public SuperHero(int powerLevel) {
                this._powerLevel= powerLevel;
              }

              ~SuperHero() {
                // Destructor code to free unmanaged resources.
    // Implicitly creates a Finalize method
              }
            }

VB.NET

Using Objects

Dim hero As SuperHero = New SuperHero
' or
Dim hero As New SuperHero

With hero
.Name = "SpamMan"
.PowerLevel = 3
End With

hero.Defend("Laura Jones")
hero.Rest() ' Calling Shared method
' or
SuperHero.Rest()

Dim hero2 As SuperHero = hero  ' Both reference the same object
            hero2.Name = "WormWoman"
            Console.WriteLine(hero.Name)   ' Prints WormWoman

hero = Nothing ' Free the object

If hero IsNothing Then _
hero = New SuperHero

Dim obj As Object = New SuperHero
If TypeOf obj Is SuperHero Then _
Console.WriteLine("Is a SuperHero object.")

' Mark object for quick disposal
Using reader 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();

// No "With" construct
hero.Name = "SpamMan";
hero.PowerLevel = 3;

hero.Defend("Laura Jones");
SuperHero.Rest(); // Calling static method

            SuperHero hero2 = hero;   // Both reference the same object
            hero2.Name = "WormWoman";
            Console.WriteLine(hero.Name);   // Prints WormWoman

hero = null ; // Free the object

if (hero == null)
hero = new SuperHero();

Object obj = new SuperHero();
if (obj is SuperHero)
Console.WriteLine("Is a SuperHero object.");

// Mark object for quick disposal
using (StreamReader reader = File.OpenText("test.txt")) {
              string line;
              while ((line = reader.ReadLine()) != null)
                Console.WriteLine(line);
            }

VB.NET

Structs

Structure StudentRecord
              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)    ' Prints Bob
            Console.WriteLine(stu2.name)  ' Prints Sue

struct StudentRecord {
              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);    // Prints Bob
            Console.WriteLine(stu2.name);   // Prints Sue

VB.NET

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

private int _size;

            public int Size {
              get {
                return _size;
              }
              set {
                if (value < 0)
                  _size = 0;
                else
                  _size = value;
              }
            }

foo.Size++;

VB.NET

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, 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

Dim WithEvents MyButton As Button ' 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) Handles MyButton.Click
              MessageBox.Show(Me, "Button was clicked", "Info", _
                MessageBoxButtons.OK, MessageBoxIcon.Information)
            End Sub

delegate void MsgArrivedEventHandler(string message);

event MsgArrivedEventHandler MsgArrivedEvent;

// Delegates must be used with events in C#

            MsgArrivedEvent += new MsgArrivedEventHandler(My_MsgArrivedEventCallback);
            MsgArrivedEvent("Test message");    // 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, "Button was clicked", "Info",
                MessageBoxButtons.OK, MessageBoxIcon.Information);
            }

VB.NET

Console I/O

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)
' or
            Console.WriteLine(name & " is " & age & " years old.")

            Dim c As Integer
            c = Console.Read()    ' Read single char
            Console.WriteLine(c)   ' 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.", name, age);
// or
            Console.WriteLine(name + " is " + age + " years old.");

int c = Console.Read(); // Read single char
Console.WriteLine(c); // Prints 65 if user enters "A"

VB.NET

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()

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();

转载于http://blog.csdn.net/minsenwu/article/details/7615210

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