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"

' 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(); 
            }

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;

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 {
               ...
            }

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
              }
            }

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);
            }

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

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++;

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); 
            }

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"

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