vb.netmvc例子 vbnet using

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VB.net中类的实例化

1.不正确

Dim abc As myClassvb.netmvc例子，定义一个可以引用myClass类型对象vb.netmvc例子的变量abc。这个abc变量存在于栈上。

abc=New myClass。New myClass创建myClass实例对象，这个对象存在于托管堆上。然后（同时）让abc引用（指向）这个对象。

abc变量在栈上，而对象在托管堆上。

abc储存的是对象的地址，而不是对象本身。

看下面的代码

Dim a As myClass,b As myClass,c As myClass

a=New myClass

b=a

c=a

整个过程中只创建了一个myClass对象，位于托管堆上。

三个myClass类型的变量a、b、c位于栈上，都指向了这一个myClass对象

2.类的成员分实例成员和静态成员

实例成员必须在实例对象上调用

静态成员可以直接调用，不需要实例对象。

相关问答

Q1: vb.net中如何用事件和委托，会C#中的事件和委托，但不知VB.net中的语法，望给个简单的例子熟悉语法。

一委托：此示例演示如何将方法与委托关联然后通过委托调用该方法。

创建委托和匹配过程

创建一个名为 MySubDelegate 的委托。

Delegate Sub MySubDelegate(ByVal x As Integer)

声明一个类，该类包含与该委托具有相同签名的方法。

Class class1

Sub Sub1(ByVal x As Integer)

MsgBox("The value of x is: " CStr(x))

End Sub

End Class

定义一个方法，该方法创建该委托的实例并通过调用内置的 Invoke 方法调用与该委托关联的方法。

Protected Sub DelegateTest()

Dim c1 As New class1

' Create an instance of the delegate.

Dim msd As MySubDelegate = AddressOf c1.Sub1

' Call the method.

msd.Invoke(10)

End Sub

二、事件

下面的示例程序阐释如何在一个类中引发一个事件，然后在另一个类中处理该事件。AlarmClock 类定义公共事件 Alarm，并提供引发该事件的方法。AlarmEventArgs 类派生自 EventArgs，并定义 Alarm 事件特定的数据。WakeMeUp 类定义处理 Alarm 事件的 AlarmRang 方法。AlarmDriver 类一起使用类，将使用 WakeMeUp 的 AlarmRang 方法设置为处理 AlarmClock 的 Alarm 事件。

该示例程序使用事件和委托和引发事件中详细说明的概念。

示例

' EventSample.vb.

Option Explicit

Option Strict

Imports System

Imports System.ComponentModel

Imports Microsoft.VisualBasic

Namespace EventSample

' Class that contains the data for

' the alarm event. Derives from System.EventArgs.

Public Class AlarmEventArgs

Inherits EventArgs

Private _snoozePressed As Boolean

Private nrings As Integer

'Constructor.

Public Sub New(snoozePressed As Boolean, nrings As Integer)

Me._snoozePressed = snoozePressed

Me.nrings = nrings

End Sub

' The NumRings property returns the number of rings

' that the alarm clock has sounded when the alarm event

' is generated.

Public ReadOnly Property NumRings() As Integer

Get

Return nrings

End Get

End Property

' The SnoozePressed property indicates whether the snooze

' button is pressed on the alarm when the alarm event is generated.

Public ReadOnly Property SnoozePressed() As Boolean

Get

Return _snoozePressed

End Get

End Property

' The AlarmText property that contains the wake-up message.

Public ReadOnly Property AlarmText() As String

Get

If _snoozePressed Then

Return "Wake Up!!! Snooze time is over."

Else

Return "Wake Up!"

End If

End Get

End Property

End Class

' Delegate declaration.

Public Delegate Sub AlarmEventHandler(sender As Object, _

e As AlarmEventArgs)

' The Alarm class that raises the alarm event.

Public Class AlarmClock

Private _snoozePressed As Boolean = False

Private nrings As Integer = 0

Private stopFlag As Boolean = False

' The Stop property indicates whether the

' alarm should be turned off.

Public Property [Stop]() As Boolean

Get

Return stopFlag

End Get

Set

stopFlag = value

End Set

End Property

' The SnoozePressed property indicates whether the snooze

' button is pressed on the alarm when the alarm event is generated.

Public Property SnoozePressed() As Boolean

Get

Return _snoozePressed

End Get

Set

_snoozePressed = value

End Set

End Property

' The event member that is of type AlarmEventHandler.

Public Event Alarm As AlarmEventHandler

' The protected OnAlarm method raises the event by invoking

' the delegates. The sender is always this, the current instance

' of the class.

Protected Overridable Sub OnAlarm(e As AlarmEventArgs)

RaiseEvent Alarm(Me, e)

End Sub

' This alarm clock does not have

' a user interface.

' To simulate the alarm mechanism it has a loop

' that raises the alarm event at every iteration

' with a time delay of 300 milliseconds,

' if snooze is not pressed. If snooze is pressed,

' the time delay is 1000 milliseconds.

Public Sub Start()

nrings += 1

If stopFlag Then

Exit Do

Else

If _snoozePressed Then

System.Threading.Thread.Sleep(1000)

If (True) Then

Dim e As New AlarmEventArgs(_snoozePressed, nrings)

OnAlarm(e)

End If

Else

System.Threading.Thread.Sleep(300)

Dim e As New AlarmEventArgs(_snoozePressed, nrings)

OnAlarm(e)

End If

Loop

End Sub

End Class

' The WakeMeUp class has a method AlarmRang that handles the

' alarm event.

Public Class WakeMeUp

Public Sub AlarmRang(sender As Object, e As AlarmEventArgs)

Console.WriteLine((e.AlarmText + ControlChars.Cr))

If Not e.SnoozePressed Then

If e.NumRings Mod 10 = 0 Then

Console.WriteLine(" Let alarm ring? Enter Y")

Console.WriteLine(" Press Snooze? Enter N")

Console.WriteLine(" Stop Alarm? Enter Q")

Dim input As String = Console.ReadLine()

If input.Equals("Y") Or input.Equals("y") Then

Return

Else

If input.Equals("N") Or input.Equals("n") Then

CType(sender, AlarmClock).SnoozePressed = True

Return

Else

CType(sender, AlarmClock).Stop = True

Return

End If

Else

Console.WriteLine(" Let alarm ring? Enter Y")

Console.WriteLine(" Stop Alarm? Enter Q")

Dim input As String = Console.ReadLine()

If input.Equals("Y") Or input.Equals("y") Then

Return

Else

CType(sender, AlarmClock).Stop = True

Return

End If

End Sub

End Class

' The driver class that hooks up the event handling method of

' WakeMeUp to the alarm event of an Alarm object using a delegate.

' In a forms-based application, the driver class is the

' form.

Public Class AlarmDriver

Public Shared Sub Main()

' Instantiates the event receiver.

Dim w As New WakeMeUp()

' Instantiates the event source.

Dim clock As New AlarmClock()

' Wires the AlarmRang method to the Alarm event.

AddHandler clock.Alarm, AddressOf w.AlarmRang

clock.Start()

End Sub

End Class

End Namespace

Q2: 用VB.NET轻松制作特效窗体

体是Windows应用程序vb.netmvc例子的基础新一代的开发工具Visual Basic Net为设计制作窗体提供了更多简单而丰富的方法无需再求助于复杂而易错的API函数 vb.netmvc例子我们就可以轻松制作多种特效窗体轻松制作透明窗体VB NET可以轻松制作出任一透明度的窗体我们只要在窗体的属性窗口中将 Opacity 属性设置为一个介于（完全透明）与（完全不透明）之间的值就可以了 Dim frm As FrmTrans = New FrmTrans()frm Opacity = frm ShowDialog() 轻松制作始终位于最上层的窗体在VB 中要制作一个始终位于最上层的窗体我们只能求助于令人头痛的API函数然而在 NET 中我们只要简单设置窗体的 TopMost 属性就可实现同样效果了vb.netmvc例子！例如 Dim frm As frmTopMost = New frmTopMost()frm TopMost = Truefrm Show() 轻松制作不可见的窗体如果要编写一个不让别人发现的隐藏程序制作不可见的窗体就是必须实现的第一步窗体的可见性通常由 Visible 属性控制但是如果希望 Windows 应用程序的主窗体在应用程序启动时不可见您将会发现将它的 Visible 属性设置为 False 的方法无效窗体总会自己显示出来（这是因为启动窗体的生存期决定了应用程序的生存期）虽然如此我们还是可以通过简单将应用程序的启动设置为一个模块从而从窗体的生存期分出应用程序的生存期轻松实现不可见的窗体在下面这个例子中窗体在特定的时间内自动隐藏（）在 Visual Basic 中右击项目并选择添加模块以将模块添加到 Windows 应用程序（）在已添加的模块（或类）内创建可作为项目启动对象的 Main 函数 Sub main()Dim f As New Form ()f Visible = FalseWhile Hour(Date Now) 如果当前时间早于点窗体自动隐藏Application DoEvents()End Whilef ShowDialog()End Sub 轻松编写托盘程序托盘程序作为一类特殊的窗体其快捷图标显示在系统托盘中窗体本身则隐藏不可见在 NET之前版本的VB中编写托盘程序是十分困难的但是VB NET提供的新的NotifyIcon组件却使VB初学者也能轻松编写一个这样的程序新建 Windows应用程序设置主窗体Opacity属性为 FormBorderStyle属性为None ShowInTaskbar属性为False 这样窗体将在启动后隐藏在窗体上放置一个NotifyIcon组件NotifyIcon 一个ContextMenu（弹出菜单）组件ContextMenu 并根据需要为ContextMenu 添加菜单项设置NotifyIcon 的ICON属性这个图标就是应用程序出现在系统托盘中的快捷图标设置NotifyIcon 的Text属性为 VB NET托盘程序这就是鼠标移动到托盘图标时弹出的文字说明设置NotifyIcon 的ContextMenu属性为ContextMenu 也就是右键单击快捷图标时的弹出菜单为ContextMenu OK 按F 运行vb.netmvc例子！几乎不用编写代码一个托盘程序就这样轻松实现了 lishixinzhi/Article/program/net/201311/13831

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