Question

我试图建立一个可以在端口上ping的服务器状态检查器。

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    If My.Computer.Network.Ping("192.168.2.10:21") Then
        PictureBox1.BackColor = Color.LimeGreen
        Label1.Text = "Online!"
        Label1.ForeColor = Color.LimeGreen

    Else
        PictureBox1.BackColor = Color.DarkRed
        Label1.Text = "Offline!"
        Label1.ForeColor = Color.DarkRed
    End If
End Sub

当我这样做时，它不会返回任何结果。没有离线或在线。

Answer 1

正如我在评论中所提到的那样ping端口不起作用。因此，您只能检查远程可用性。用"ipaddress:port"编写应该抛出错误

Ping通过发送Internet控制消息协议（ICMP）
进行操作

其他方法是使用TCP

在这里，我为Pinging port和Neetwork.Ping写了正确的方法

Private Function checkport(hostname As String, port As Integer
                             ) As Boolean
    Dim client As New TcpClient(AddressFamily.InterNetwork)


    client.BeginConnect(hostname, port,
                        Sub(x)
                            Dim tcp As TcpClient = CType(x.AsyncState, TcpClient)
                            Try
                                tcp.EndConnect(x)
                                SetIndicators(True)

                            Catch ex As Exception
                                'error
                                SetIndicators(False)

                            End Try
                            tcp.Close()
                        End Sub, client
                        )


    Return (False)
End Function

'Cross-thread safe code using InvokeRequired Pattern
Private Sub SetIndicators(ByVal ok As Boolean)

    If Me.Label1.InvokeRequired Then
        Dim d As New Action(Of Boolean)(AddressOf SetIndicators)
        Me.Invoke(d, ok)
    Else
        If ok = True Then
            Label1.Text = "Online!"
            Label1.ForeColor = Color.LimeGreen
        Else
            Label1.Text = "Offline!"
            Label1.ForeColor = Color.DarkRed
        End If
    End If
End Sub

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    Try
       ' If My.Computer.Network.Ping("192.168.1.1") Then

          '  Label1.Text = "Online!"
          '  Label1.ForeColor = Color.LimeGreen

       ' Else
           ' Label1.Text = "Offline!"
           ' Label1.ForeColor = Color.DarkRed
       ' End If 
        SetIndicators(My.Computer.Network.Ping("stackoverflow.com")) 
    Catch ex As Exception
        'error occured
        MessageBox.Show(ex.Message)

    End Try

End Sub

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
    'result can be returned late according connection timeout
    checkport("stackoverflow.com", 450) 
End Sub

Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
    'should return online cause http port accessible
    checkport("stackoverflow.com", 80)
End Sub

VB.NET ping端口

1 个答案: