窗体启动的时候自动循环一条线程，可是输不值到外面

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim Thread1 As New System.Threading.Thread(AddressOf abc)
Thread1.Start()
Label2.Text = j

'Thread1.Join()
End Sub

Public Sub abc()
Do
If i Then
j += 1
If j = 500000 Then j = 0
Application.DoEvents()
End If
Loop

End Sub

我要实现的功能：窗体启动的时候，不停地执行线程1：线程1里面有一个判断语句，If i Then,根据外面的按钮改变i的 Boolean值，控制循环，同时当i=true时，执行j+=1,并且在窗体中显示i,j的当时值，奇怪的时候，J的值输出不了到窗体中。求方法求解析求帮助~
[解决办法]
给分吧

Public Class Form1
    Private i As Boolean = True, j As Integer = 0
    Public Delegate Sub DelegateSub(ByVal text As String)

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        i = Not i
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim Thread1 As New System.Threading.Thread(AddressOf abc)
        Thread1.Start()
    End Sub

    Private Sub SetText(ByVal value As String)
        Label2.Text = value
    End Sub
    Public Sub abc()
        Do
            If i Then
                j += 1
                If j = 500000 Then j = 0
                Invoke(New DelegateSub(AddressOf SetText), j.ToString)
                Application.DoEvents()
            End If
        Loop

    End Sub
End Class