VB.net 与线程

Imports System.Threading
Imports System

Public Class Form1
    Dim th1, th2 As Thread
    Public Sub Method1()
        Dim i As Integer
        For i =  To 

            If Me.Label1.BackColor = Color.DarkRed Then
                Me.Label1.BackColor = Color.Gold
            End If
            System.Threading.Thread.Sleep()
            If Me.Label1.BackColor = Color.Gold Then
                Me.Label1.BackColor = Color.DarkRed
            End If
            System.Threading.Thread.Sleep()
        Next

    End Sub
    Public Sub Method2()
        Dim i As Integer
        For i =  To
            If Me.Label2.BackColor = Color.DarkRed Then
                Me.Label2.BackColor = Color.Gold
            End If
            System.Threading.Thread.Sleep()
            If Me.Label2.BackColor = Color.Gold Then
                Me.Label2.BackColor = Color.DarkRed
            End If
            System.Threading.Thread.Sleep()
        Next
    End Sub
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Me.Label1.BackColor = Color.DarkRed
        Me.Label2.BackColor = Color.DarkRed

        th1 = New Thread(New ThreadStart(AddressOf Method1))
        th1.Start()

        th2 = New Thread(New ThreadStart(AddressOf Method2))
        th2.Start()
        System.Threading.Thread.Sleep()
    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.FormClosed
        th1.Abort() ' 调用此方法通常会终止线程。
        th2.Abort()
    End Sub

End Class