VB .NET 鼠标指针自动移动问题

Imports System.Collections.Generic
Imports System.Drawing
Imports System.Runtime.InteropServices
'窗体上任意拉出两个标签控件，一个按钮控件
'测试环境 winXP + .NET 2008
'其它环境未测试过
Public Class Form1
    <DllImport("User32")> _
    Public Shared Sub SetCursorPos(ByVal x As Integer, ByVal y As Integer)
    End Sub

    Private Mouse1 As New Point(1, 1)
    Private Mouse2 As New Point(1, 1)
    Private p As New Point(1, 1)

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Show()
        Me.AcceptButton = Button1
        Button1.Text = "停止测试"
        Timer1.Interval = 2000
        Mouse1 = Label1.PointToScreen(p)
        Mouse2 = Label2.PointToScreen(p)
        Timer1.Start()
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If Button1.Text = "停止测试" Then
            Timer1.Stop()
            Button1.Text = "开始测试"
        Else
            Timer1.Start()
            Button1.Text = "停止测试"
        End If
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Static i As Integer = 0
        i += 1
        If i Mod 2 <> 0 Then
            SetCursorPos(Mouse1.X + Label1.Width / 2, Mouse1.Y + Label1.Height / 2)
        Else
            SetCursorPos(Mouse2.X + Label2.Width / 2, Mouse2.Y + Label2.Height / 2)
        End If
    End Sub

    Private Sub Form1_Move(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Move
        '窗体移动时重新获取坐标
        Mouse1 = Label1.PointToScreen(p)
        Mouse2 = Label2.PointToScreen(p)
    End Sub

    Private Sub Form1_Resize(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Resize
        '窗体调整大小时，重新获取坐标
        Mouse1 = Label1.PointToScreen(p)
        Mouse2 = Label2.PointToScreen(p)
    End Sub
End Class