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我正在尝试开发一个使用 vb.net 管理防火墙端口的代码。第一部分是列出所有启用的端口。所以我正在尝试这段代码：

Function portsList()
    Dim ports As INetFwOpenPorts
    Dim port As INetFwOpenPort
    Dim myPorts() As INetFwOpenPorts

    Dim NetFwMgrType As Type = Type.GetTypeFromProgID("HNetCfg.FwMgr", False)
    Dim mgr As INetFwMgr = DirectCast(Activator.CreateInstance(NetFwMgrType), INetFwMgr)
    ports = DirectCast(mgr.LocalPolicy.CurrentProfile.GloballyOpenPorts, INetFwOpenPorts)
    Dim enumerate As System.Collections.IEnumerator = ports.GetEnumerator()

    Dim i As Integer
    While enumerate.MoveNext()
        port = DirectCast(enumerate.Current, INetFwOpenPort)
        myPorts(i) = port
        i += 1
    End While


    Dim portAsString() As String
    For j As Integer = 0 To i
        portAsString(j) = myPorts(j).ToString
    Next

    Return portAsString
End Function


Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click

    Dim ports() As String = portsList()
    Dim n As String = ports.Length
    Dim newString As String = ""

    For h As Integer = 0 To n
        newString = ports(h) & vbNewLine
    Next

    RichTextBox1.Text = newString
End Sub

我想要做的是Richtextbox1在单击后列出所有端口Button4。我得到的错误是：

NullReferenceException 未处理。你调用的对象是空的。

我是 Vb 新手，我该如何克服这个问题？

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1 回答 1

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尝试这个：

For port As Integer = 1 to maxPorts
    Dim host As String = "192.168.1.7"
    Dim hostadd As Net.IPAddress = Net.Dns.GetHostEntry(host).AddressList(0)
    Dim EPhost As New Net.IPEndPoint(hostadd, port)
    Dim s As New Net.Sockets.Socket(Net.Sockets.AddressFamily.InterNetwork, Net.Sockets.SocketType.Stream, Net.Sockets.ProtocolType.Tcp)

    Try
        s.Connect(EPhost)
    Catch
    End Try
    If s.Connected Then
        'Port opened
    Else
        'Port closed
    End If
Next

在这里你有完整的项目。

于 2013-05-08T11:34:51.227 回答