重載VB.NET事件？

Question

在我的VB.NET類中，我有一些如下代碼：

Public Class barClass

Private Function foo(data as string)
    msgbox("Data is a string: " & data)
End Function

Private Function foo(data as integer)
    msgbox("Data is an integer: " & data
End Function

End Class

顯然，這可以讓您將字符串或整數傳遞給foo 。

我認為我可以為事件做同樣的事情，所以我嘗試：

Public Event FooRaised(data as string)
Public Event FooRaised(data as integer)

我以為我可以通過傳遞從foo獲得的任何數據來引發事件，但是我得到一個錯誤，說我不能這樣做（那個FooRaised已經被聲明了）。

我該如何實現？

Answer 1

使用Object參數聲明一個事件，然后檢查類型以對其進行處理：

Public Class Form1

  Public Event Foo(o As Object)

  Sub FooHandler(o As Object) Handles Me.Foo
    If o.GetType Is GetType(Integer) Then
      Dim i As Integer = DirectCast(o, Integer)
      i += 1 'add one to the integer value'
      MsgBox(i.ToString)
    ElseIf o.GetType Is GetType(String) Then
      Dim s As String = DirectCast(o, String)
      s &= "!!" 'append exclamation marks'
      MsgBox(s)
    End If
  End Sub

  Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    RaiseEvent Foo(21)
    RaiseEvent Foo("a string value")
  End Sub
End Class