主题：[求助]如何判断指定端口是否有效，是否被占用？

方法一

Dim hl As new Net.HttpListener
try
    hl.Prefixes.Add("http://*:80/")
    hl.start
catch ex As exception
    msgbox("被占用了")
finally
    hl.close
End try

方法二

Dim IPs = System.Net.NetworkInformation.IPGlobalProperties.GetIPGlobalProperties
Dim ipEndPoints = ips.GetActiveTcpListeners
Dim inUse As Boolean = False
For Each endPoint As object In ipEndPoints
    If endPoint.Port = 80 Then
        inUse = True
        Exit For
    End If
Next

Return inUse