這些問(wèn)題的確頭大,vb的dll、ocx等,在vb點(diǎn)虐 里都不好調(diào)用,主要是來(lái)要注冊(cè)組件等,麻煩。建議全部用vb點(diǎn)虐 寫就好了,
成都創(chuàng)新互聯(lián)專注于企業(yè)成都營(yíng)銷網(wǎng)站建設(shè)、網(wǎng)站重做改版、洮南網(wǎng)站定制設(shè)計(jì)、自適應(yīng)品牌網(wǎng)站建設(shè)、H5開(kāi)發(fā)、商城建設(shè)、集團(tuán)公司官網(wǎng)建設(shè)、成都外貿(mào)網(wǎng)站建設(shè)、高端網(wǎng)站制作、響應(yīng)式網(wǎng)頁(yè)設(shè)計(jì)等建站業(yè)務(wù),價(jià)格優(yōu)惠性價(jià)比高,為洮南等各大城市提供網(wǎng)站開(kāi)發(fā)制作服務(wù)。
一委托:此示例演示如何將方法與委托關(guān)聯(lián)然后通過(guò)委托調(diào)用該方法。
創(chuàng)建委托和匹配過(guò)程
創(chuàng)建一個(gè)名為 MySubDelegate 的委托。
Delegate Sub MySubDelegate(ByVal x As Integer)
聲明一個(gè)類,該類包含與該委托具有相同簽名的方法。
Class class1
Sub Sub1(ByVal x As Integer)
MsgBox("The value of x is: " CStr(x))
End Sub
End Class
定義一個(gè)方法,該方法創(chuàng)建該委托的實(shí)例并通過(guò)調(diào)用內(nèi)置的 Invoke 方法調(diào)用與該委托關(guān)聯(lián)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
下面的示例程序闡釋如何在一個(gè)類中引發(fā)一個(gè)事件,然后在另一個(gè)類中處理該事件。AlarmClock 類定義公共事件 Alarm,并提供引發(fā)該事件的方法。AlarmEventArgs 類派生自 EventArgs,并定義 Alarm 事件特定的數(shù)據(jù)。WakeMeUp 類定義處理 Alarm 事件的 AlarmRang 方法。AlarmDriver 類一起使用類,將使用 WakeMeUp 的 AlarmRang 方法設(shè)置為處理 AlarmClock 的 Alarm 事件。
該示例程序使用事件和委托和引發(fā)事件中詳細(xì)說(shuō)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()
Do
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
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
End If
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 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
軟糖來(lái)回答羅。
“調(diào)用事件”有歧義,你的意思是不是下面兩種:
調(diào)用事件處理方法
直接調(diào)用對(duì)象名.方法名
'例如有這樣一個(gè)按鈕點(diǎn)擊事件處理程序
Private?Sub?Button1_Click(sender?As?Object,?e?As?EventArgs)?Handles?Button1.Click
秒表.Start()
End?Sub
'調(diào)用它直接用
Button1_Click(me,?new?EventArgs())
引發(fā)事件
Button1.Click.Invoke(me,?new?EventArgs())
另外?RaiseEvent 也可以引發(fā)事件,但不能使用 RaiseEvent?來(lái)引發(fā)派生窗體的控件事件,只有自己定義的類的事件才能用它引發(fā)。
如滿意,請(qǐng)采納,謝謝。
聲明事件只需用
private event 事件名稱(參數(shù)表)
在通用部分聲明
引用這個(gè)詞不太恰當(dāng),應(yīng)該說(shuō)是觸發(fā)
在需要觸發(fā)的地方用
raiseevent 事件名稱(參數(shù)表)就可以了