Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
        AddHandler Button1.Click, AddressOf Dosomething   
    End Sub
    Private Sub Dosomething(sender As Object, e As EventArgs)
        MsgBox("hell")
    End Sub
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim obj As New clsCAL
        obj.A = 1
        obj.B = 5
        MsgBox(obj.C)

        obj.A = 2
        MsgBox(obj.C)
    End Sub
End Class

1     AddHandler Button1.Click, AddressOf Dosomething    這行程式碼的含義是，當完成了Button1的單擊後，自動呼叫Dosomething函式。由於註冊事件的程式碼是在窗體載入的過程中完成的，所以就達到了有條件呼叫事件的響應程式碼的目的

2   Button1單擊後，事件的呼叫順序為    Button1_Click(----->  Dosomething