VB 多播委托

 Dim DelegetSub1 As testDelegetSub = New testDelegetSub(AddressOf testDelegateSub2)
    Dim DelegetSub2 As testDelegetSub = New testDelegetSub(AddressOf testDelegateSub3)
    Dim DelegetSub3 As testDelegetSub = System.Delegate.Combine(DelegetSub1, DelegetSub2)

    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
        DelegetSub3() ‘先调用DelegetSub1、DelegetSub2
        DelegetSub3 = System.Delegate.Remove(DelegetSub3, DelegetSub1) ‘移除DelegetSub3 中的DelegetSub1  再赋值给DelegetSub3
        DelegetSub3() ‘其实是只调用DelegetSub2

        DelegetSub3 = System.Delegate.Remove(DelegetSub3, DelegetSub1) ‘已经移除过DelegetSub1 但不会报错
        DelegetSub3 = System.Delegate.Remove(DelegetSub3, DelegetSub2)

        If DelegetSub3 Is Nothing Then
            MessageBox.Show("DelegetSub3此委托为空不能调用")
        Else
            DelegetSub3() ‘ DelegetSub3里面为空时调用会报错  所有要先判断
        End If
    End Sub


    Private Sub testDelegateSub2()
        MessageBox.Show("委托测试成功111！！！")
        Me.Text = "委托测试成功111！！！"
    End Sub
    Private Sub testDelegateSub3()
        MessageBox.Show("委托测试成功222！！！")
    End Sub