Imports System.IO
Imports System.Threading
Imports System.Diagnostics

Public Class Form1

Dim A(254) As String

 Function ping(ByVal IP As Integer) As String

Dim IPAddress As String
IPAddress = "10.0.2." & IP
If My.Computer.Network.Ping(IPAddress) Then
A(IP) = "OK"
Else
A(IP) = "NG"
End If
End Function

Private Sub Button1_Click_1(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles Button1.Click

Dim mythread(254) As Thread

Dim i As Integer
‘创建线程对象

For i = 1 To 254
mythread(i) = New Thread(AddressOf ping)
Next

‘执行线程
For i = 1 To 254
mythread(i).Start(i)
Next

‘等待线程完成
For i = 1 To 254
mythread(i).Join()
TextBox1.Text = A(i)

Next

End Sub

End Class