Question

我想消耗我编写的类模块的事件。类模块看起来像这样

''CError64Row
Public Event ErrorClicked(ByVal row As Integer, ByVal column As Integer)

Public WithEvents lblDescription As MSForms.Label
Public WithEvents lblFile As MSForms.Label
Public WithEvents lblRow As MSForms.Label
Public WithEvents lblCol As MSForms.Label

Public row As Long
Public col As Long

Private Sub lblDescription_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
   RaiseEvent ErrorClicked(row, col)
End Sub

Private Sub lblFile_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
   RaiseEvent ErrorClicked(row, col)
End Sub

Private Sub lblRow_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
   RaiseEvent ErrorClicked(row, col)
End Sub

Private Sub lblCol_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
   RaiseEvent ErrorClicked(row, col)
End Sub

在我的一种表单中，我创建了CError64Row对象

Private m_Elements As Long

Private mErrors() As CError64Row

Private Sub UserForm_Initialize()
    m_Elements = 0
End Sub

Public Function SetError(text As String, filename As String, row As Integer, column As Integer) As String
    Dim ctl As control

   ReDim Preserve mErrors(m_Elements + 1)

    Dim errorRow As CError64Row
    Set errorRow = New CError64Row
    Set mErrors(m_Elements) = errorRow

    mErrors(m_Elements).row = row
    mErrors(m_Elements).col = column
    Set mErrors(m_Elements).lblDescription = Me.Controls.Add("forms.label.1")
    With mErrors(m_Elements).lblDescription
        .Left = 35
        .height = 14
        .Top = 18 + (m_Elements) * 14
        .width = 631
        .Caption = text
    End With

    Set mErrors(m_Elements).lblFile = Me.Controls.Add("forms.label.1")
    With mErrors(m_Elements).lblFile
        .Left = 665
        .height = 14
        .Top = 18 + (m_Elements) * 14
        .width = 106
        .Caption = filename
    End With

    Set mErrors(m_Elements).lblRow = Me.Controls.Add("forms.label.1")
    With mErrors(m_Elements).lblRow
        .Left = 770
        .height = 14
        .Top = 18 + (m_Elements) * 14
        .width = 36
        .Caption = CStr(row)
    End With

    Set mErrors(m_Elements).lblCol = Me.Controls.Add("forms.label.1")
    With mErrors(m_Elements).lblCol
        .Left = 805
        .height = 14
        .Top = 18 + (m_Elements) * 14
        .width = 36
        .Caption = CStr(column)
    End With
    m_Elements = m_Elements + 1
End Function

Public Sub CError64Row_ErrorClicked(ByVal row As Integer, ByVal column As Integer)
    MsgBox "MSG received"
End Sub

我想收到ErrorClicked事件，但不确定如何订阅该事件。我在这个答案Is it possible to create and handle a custom Event in a Customized UserForm?中看到，我可以通过

“订阅”

私人子[Provider] _MemberName

但是我怀疑这是否适用于在方法中创建的对象。如何订阅在方法中创建的对象的事件？

Answer 1

Private mErrors() As CError64Row

您的“事件提供者”对象位于此mErrors数组中-您需要以某种方式声明它WithEvents，但这是非法的：

Private WithEvents mErrors() As CError64Row

问题不是对象是在方法中创建的-创建对象的方式没有区别。问题在于您无法使表单处理由引用位于数组/集合而不是Private WithEvents字段中的对象转发的事件。

解决方案是使自定义类与表单对话-您已经对此有了引用：

Private Sub lblDescription_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
    Dim parentForm As TheFormClass
    Set parentForm = lblDescription.Parent
    parentForm.HandleErrorClicked(row, col)
End Sub

现在，这将TheFormClass形式与自定义控件类紧密结合在一起，这并不理想-如果我们需要以另一种形式重用该类怎么办？

我们可以晚到：

Private Sub lblDescription_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
    Dim parentForm As Object
    Set parentForm = lblDescription.Parent
    parentForm.HandleErrorClicked(row, col)
End Sub

但是随后我们失去了编译时验证，并且不能保证parentForm有一个HandleErrorClicked方法-如果该方法不存在，我们将因错误438而崩溃。 / p>

除非...除非我们使用一个接口（例如非常简单的IErrorView类）将其正规化，否则它可能看起来像这样：

Option Explicit
Public Sub HandleErrorClicked(ByVal row As Long, ByVal col As Long)
End Sub

...并使表单类实现此接口：

Implements IErrorView

Private Sub IErrorView_HandleErrorClicked(ByVal row As Long, ByVal col As Long)
    ' there's the handler!
End Sub

现在，自定义控件类可以与实现IErrorView接口的任何形式一起使用，并且我们可以重新获得编译时验证：

Private Sub lblDescription_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
    Dim parentForm As IErrorView
    Set parentForm = lblDescription.Parent
    parentForm.HandleErrorClicked(row, col)
End Sub

消费/订阅类模块的自定义事件

1 个答案: