讨论个砖家级问题：两个类之间如何发送接收事件

[dafu2003]

两个类：class1 class2,
现在想要在他们之间收发自定义事件，比如在class1中 raiseEvents processMessage(msgID, msg as string),
在class2中如何接受？

[lyserver]

[Quote=引用楼主 dafu2003 的回复:]
两个类：class1 class2,
现在想要在他们之间收发自定义事件，比如在class1中 raiseEvents processMessage(msgID, msg as string),
在class2中如何接受？
[/Quote]
用WithEvents就行了。

[咸清]

方法很多，比如说 DDE

[王二.麻子]

好像是不能在类中接受处理事件。
在类中定义对class1的对象时 public withevents mm as class1会出错

[咸清]

高手现在都过年去了？
~~这样的帖子得顶啊

[jiashie]

clsA内部引用clsB
private mListener as clsB

clsB内部引用clsA
private mListener as clsA

然后在raiseevents时，直接调用mListener.OnMyEvent(...)

'// IEventListener
Option Explicit
'Public Event MyEvent(ByVal a As String)

Public Sub OnMyEvent(ByVal a As String)

End Sub

'// clsA
Option Explicit
Implements IEventListener

'Public Event MyEvent(ByVal a As String)

Private mListener As IEventListener

Private Sub IEventListener_OnMyEvent(ByVal a As String)
    Debug.Print "handled in clsA," & a
End Sub

Public Function AddEventListener(ByRef objListener As IEventListener)
    Set mListener = objListener
End Function

Public Function SetValue(ByVal a As String)
    'RaiseEvent MyEvent(a)
    If Not (mListener Is Nothing) Then
        mListener.OnMyEvent (a)
    End If
    
End Function

'// clsB
Option Explicit

Implements IEventListener
'Public Event MyEvent(ByVal a As String)

Private mListener As IEventListener

Private Sub IEventListener_OnMyEvent(ByVal a As String)
    Debug.Print "handled in clsB," & a
End Sub

Public Function AddEventListener(ByRef objListener As IEventListener)
    Set mListener = objListener
End Function

Public Function SetValue(ByVal a As String)
    'RaiseEvent MyEvent(a)
    If Not (mListener Is Nothing) Then
        mListener.OnMyEvent (a)
    End If
End Function

'调用示例
Dim a As New clsA
Dim b As New clsB

a.AddEventListener b
b.AddEventListener a

a.SetValue (20)
b.SetValue (30)

Set a = Nothing
Set b = Nothing

纯新手，高手表笑

[王二.麻子]

说错了，好久没VB了[Quote=引用 2 楼 spt_petrolor 的回复:]
好像是不能在类中接受处理事件。
在类中定义对class1的对象时 public withevents mm as class1会出错
[/Quote]
在class1里面不能创建class2的实例。但是可以对其他地方创建的class2的实例的引用，用这个引用可以处理class1的事件
以前写过一个这样的程序。
在class2里面：public withevents mm as class1
然后写mm的事件处理过程。
在form1里面创建class1实例cls1，class2实例cls2，并且set cls2.mm=cls1
不知道为什么这么麻烦。

类里面，withevents不能和new一起，set mm=new **也老出错误。

[king06]

[Quote=引用 2 楼 spt_petrolor 的回复:]
好像是不能在类中接受处理事件。
在类中定义对class1的对象时 public withevents mm as class1会出错
[/Quote]
可以定义啊
form1:

Private Sub Command1_Click()
    Dim cl2 As New Class2
    Call cl2.test2
End Sub

class1:

Public Event processMessage(ByVal msgID As Long, ByRef msg As String)
Public Sub test1()
    RaiseEvent processMessage(2, "nothing")
End Sub

class2:

Private WithEvents mcl1 As Class1
Private Sub mcl1_processMessage(ByVal msgID As Long, msg As String)
    MsgBox msgID & ":" & msg
End Sub
Public Sub test2()
    Set mcl1 = New Class1
    Call mcl1.test1
End Sub

[king06]

哦,上面6F自己说明了...