知识大全 ASP.NET入门—语法介绍

Posted 2022-07-17 事件

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声明变量

Dim x As IntegerDim s As StringDim s s As StringDim o Implicitly ObjectDim obj As New Object()Public name As String
var x : int;var s : String;var s : String s : String;var o;var obj : Object = new Object();var name : String;

语句输出

Response Write( foo );

代码注释

） This is a ment
）// This is a ment
）/*　　This　　is　　a　　multiline　　ment　*/

声明简单属性

Public Property Name As String
Get        Return End Get
Set    = Value End Set
End Property
function get name() : String         return ;
function set name(value : String)     = value;

声明索引属性

Default Indexed PropertyPublic Default ReadOnly Property DefaultProperty(Name As String) As String Get Return CStr(lookuptable(name)) End GetEnd Property

访问索引属性

Dim s value As Strings = Request QueryString( Name )value = Request Cookies( Key ) Value
Note that default non indexed properties must be explicitly named in VB
var s : String = Request QueryString( Name );var value : String = Request Cookies( key );

声明和使用枚举

Declare the EnumerationPublic Enum MessageSize
Small = Medium = Large = End Enum
Create a Field or PropertyPublic MsgSize As MessageSize
Assign to the property using the Enumeration valuesMsgSize = small
// Declare the Enumerationpublic enum MessageSize
Small = Medium = Large =
// Create a Field or Propertypublic var msgsize:MessageSize;
// Assign to the property using the Enumeration valuesmsgsize = Small;

声明和使用方法

Declare a void return functionSub VoidFunction() End Sub
Declare a function that returns a valueFunction StringFunction() As String     Return CStr(val)End Function
Declare a function that takes and returns valuesFunction ParmFunction(a As String b As String) As String     Return CStr(A & B)End Function
Use the FunctionsVoidFunction()Dim s As String = StringFunction()Dim s As String = ParmFunction( Hello World! )
// Declare a void return functionfunction voidfunction() : void
// Declare a function that returns a valuefunction stringfunction() : String     return String(val);
// Declare a function that takes and returns valuesfunction parmfunction(a:String b:String) : String     return String(a + b);
// Use the Functionsvoidfunction();var s :String = stringfunction();var s :String = parmfunction( Hello World! );

数组

Dim a( ) As String    a( ) =     a( ) =     a( ) =
    Dim a( ) As String    a( ) =     a( ) =     a( ) =
    var a : String[] = new String[ ];    a[ ] = ;    a[ ] = ;    a[ ] = ;
    var a : String[][] = new String[ ][ ];    a[ ][ ] = ;    a[ ][ ] = ;    a[ ][ ] = ;

初始化

Dim s As String = Hello World Dim i As Integer = Dim a() As Double =
var s : String = Hello World ;var i : int = ;var a : double[] = [ ];

If 语句

if (Request QueryString != null)
If Not (Request QueryString = Nothing) End If
if (Request QueryString != null)

Case 语句

switch (FirstName) case John :        break; case Paul :        break; case Ringo :        break; default:        break;
Select Case FirstName Case John     Case Paul     Case Ringo     Case Else    End Select
switch (FirstName) case John :        break; case Paul :        break; case Ringo :        break; default:        break;

For 循环

for (int i= ; i< ; i++) a(i) = test ;
Dim I As Integer For I = To a(I) = test Next
for (var i : int = ; i < ; i++) a[i] = test ;

While 循环

int i = ;while (i< ) Console WriteLine(i ToString()); i += ;
Dim I As IntegerI = Do While I < Console WriteLine(I ToString()) I += Loop
var i : int = ;while (i < ) Console WriteLine(i); i += ;

异常处理

try     // Code that throws exceptions catch(OverflowException e)     // Catch a specific exception catch(Exception e)     // Catch the generic exceptions finally     // Execute some cleanup code
Try    Code that throws exceptionsCatch E As OverflowException    Catch a specific exceptionCatch E As Exception    Catch the generic exceptionsFinally    Execute some cleanup codeEnd Try
try     // Code that throws exceptions catch(e:OverflowException)     // Catch a specific exception catch(e:Exception)     // Catch the generic exceptions finally     // Execute some cleanup code

字符串连接

// Using StringsString s ;String s = hello ;s += world ;s = s + !!! ;
// Using StringBuilder class for performanceStringBuilder s = new StringBuilder();s Append( hello );s Append( world );s Append( !!! );
Using StringsDim s s As Strings = hello s &= world s = s & !!!
Using StringBuilder class for performanceDim s As New StringBuilder()s Append( hello )s Append( world )s Append( !!! )
// Using Stringsvar s : String;var s : String = hello ;s += world ;s = s + !!! ;
// Using StringBuilder class for performancevar s :StringBuilder = new StringBuilder();s Append( hello );s Append( world );s Append( !!! );

事件处理程序委托

void MyButton_Click(Object sender                     EventArgs E)
Sub MyButton_Click(Sender As Object                    E As EventArgs) End Sub
function MyButton_Click(sender : Object                         E : EventArgs)

声明事件

// Create a public eventpublic event EventHandler MyEvent;
// Create a method for firing the eventprotected void OnMyEvent(EventArgs e) MyEvent(this e);
Create a public eventPublic Event MyEvent(Sender as Object E as EventArgs)
Create a method for firing the eventProtected Sub OnMyEvent(E As EventArgs) RaiseEvent MyEvent(Me E)End Sub
JScript does not support the creation of events JScript can onlyconsume events by declaring event handler delegates and adding thosedelegates to the events of another control

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 ChangeEventHandlerRemoveHandler Control Change AddressOf Me ChangeEventHandler
Control Change += this ChangeEventHandler;Control Change = this ChangeEventHandler;

强制类型转换

MyObject obj = (MyObject)Session[ Some Value ];IMyObject iObj = obj;
Dim obj As MyObjectDim iObj As IMyObjectobj = Session( Some Value )iObj = CType(obj IMyObject)
var obj : MyObject = MyObject(Session( Some Value ));var iObj : IMyObject = obj;

转换

int i = ;String s = i ToString();double d = Double Parse(s);
Dim i As IntegerDim s As StringDim d As Double
i = s = i ToString()d = CDbl(s)
See also CDbl( ) CStr( )
var i : int = ;var s : String = i ToString();var d : double = Number(s);

带继承的类定义

using System;
namespace MySpace
public class Foo : Bar
    int x;
    public Foo() x = ;     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 =     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 = ;     function Add(x : int) this x += x;     override function GetNum() : int return x;
// jsc /out:libraryjs dll library js

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 FunctionEnd Class
public class MyClass implements IEnumerable
    function IEnumerable GetEnumerator() : IEnumerator

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

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 );

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