ASP.NET入门—语法介绍[2]

    18.声明事件

// Create a public event
public event EventHandler MyEvent;

// Create a method for firing the event
protected void OnMyEvent(EventArgs e) {
      MyEvent(this, e);
}

' Create a public event
Public Event MyEvent(Sender as Object, E as EventArgs)

' Create a method for firing the event
Protected Sub OnMyEvent(E As EventArgs)
    RaiseEvent MyEvent(Me, E)
End Sub

JScript does not support the creation of events.  JScript can only
consume events by declaring event handler delegates and adding those
delegates to the events of another control.

    19.向事件添加事件处理程序或从事件移除事件处理程序

Control.Change += new EventHandler(this.ChangeEventHandler);
Control.Change -= new EventHandler(this.ChangeEventHandler);

AddHandler Control.Change, AddressOf Me.ChangeEventHandler
RemoveHandler Control.Change, AddressOf Me.ChangeEventHandler

Control.Change += this.ChangeEventHandler;
Control.Change -= this.ChangeEventHandler;

    20.强制类型转换

MyObject obj = (MyObject)Session["Some Value"];
IMyObject iObj = obj;

Dim obj As MyObject
Dim iObj As IMyObject
obj = Session("Some Value")
iObj = CType(obj, IMyObject)

var obj : MyObject = MyObject(Session("Some Value"));
var iObj : IMyObject = obj;

    21.转换

int i = 3;
String s = i.ToString();
double d = Double.Parse(s);

Dim i As Integer
Dim s As String
Dim d As Double

i = 3
s = i.ToString()
d = CDbl(s)

' See also CDbl(...), CStr(...), ...

var i : int = 3;
var s : String = i.ToString();
var d : double = Number(s);

    22.带继承的类定义

using System;

namespace MySpace {

  public class Foo : Bar {

    int x;

    public Foo() { x = 4; }
    public void Add(int x) { this.x += x; }
    override public int GetNum() { return x; }
  }

}

// csc /out:librarycs.dll /t:library
// library.cs

Imports System

Namespace MySpace

  Public Class Foo : Inherits Bar

    Dim x As Integer

    Public Sub New()
      MyBase.New()
      x = 4
    End Sub

    Public Sub Add(x As Integer)
      Me.x = Me.x + x
    End Sub

    Overrides Public Function GetNum() As Integer
       Return x
    End Function

  End Class

End Namespace

' vbc /out:libraryvb.dll /t:library
' library.vb

import System;

package MySpace {

  class Foo extends Bar {

    private var x : int;

    function Foo() { x = 4; }
    function Add(x : int) { this.x += x; }
    override function GetNum() : int { return x; }
  }

}

// jsc /out:libraryjs.dll library.js

    23.实现接口

public class MyClass : IEnumerable {
 ...

    IEnumerator IEnumerable.GetEnumerator() {
         ...
    }
}

Public Class MyClass : Implements IEnumerable
 ...

    Function IEnumerable_GetEnumerator() As IEnumerator Implements IEnumerable.GetEnumerator
         ...
    End Function
End Class

public class MyClass implements IEnumerable {
 ...

    function IEnumerable.GetEnumerator() : IEnumerator {
         ...
    }
}

    24.带 Main 方法的类定义

using System;

public class ConsoleCS {

  public ConsoleCS() {
    Console.WriteLine("Object Created");
  }

  public static void Main (String[] args) {
    Console.WriteLine("Hello World");
    ConsoleCS ccs = new ConsoleCS();
  }

}

// csc /out:consolecs.exe /t:exe console.cs

Imports System

Public Class ConsoleVB

  Public Sub New()
    MyBase.New()
    Console.WriteLine("Object Created")
  End Sub

  Public Shared Sub Main()
    Console.WriteLine("Hello World")
    Dim cvb As New ConsoleVB
  End Sub

End Class

' vbc /out:consolevb.exe /t:exe console.vb

class ConsoleCS {

  function ConsoleCS() {
    print("Object Created");
  }

  static function Main (args : String[]) {
    print("Hello World");
    var ccs : ConsoleCS = new ConsoleCS();
  }
}

// jsc /out:consolejs.exe /exe console.js

    25.标准模块

using System;

public class Module {

public static void Main (String[] args) {
  Console.WriteLine("Hello World");
}

}
// csc /out:consolecs.exe /t:exe console.cs

Imports System

Public Module ConsoleVB

  Public Sub Main()
    Console.WriteLine("Hello World")
  End Sub

End Module

' vbc /out:consolevb.exe /t:exe console.vb

print("Hello World");