vb.net網路連線 vb如何联网

vb.net 检测网络连接既然从网上找的实例没问题 , 也许就是调用的时候没出来或者在检测网卡当中出现了问题 。
求大神指点vb.net 怎么判断 网络是否连接 和取本机局域网IP和互联网IP你这段代码可以获得该主机名下的所有ip , 每个ip地址都是有类型簇的 , 可以区别本地地址和网络地址、ip6地址 。
你获取索引为0的ip,不一定是正确的网络地址,它有时顺序在中间,在后面 。
应该获取所有ip,再通过ip地址簇类型区分
判断连接本身有一个函数,不过有时没联网也是真 。
可以用ping,ping百度、ping访问速度快、不经常维护断线的网络主机 。
vb.net中如何判断网络连接?新建模块
Function IsHearOK(ByVal URL As String) As Boolean'判断网页是否存在函数
Dim XMLObject As Object, ReturnType As String
XMLObject = CreateObject("Microsoft.XMLHTTP")
XMLObject.Open("GET", URL, False)
XMLObject.setRequestHeader("CONTENT-TYPE", "application/x-www-form-urlencoded")
XMLObject.setRequestHeader("Range", "bytes=1-255")
Try
XMLObject.Send()
If XMLObject.Status = 200 Or XMLObject.Status = 206 Then
ReturnType = XMLObject.getResponseHeader("CONTENT-TYPE")
If UCase(ReturnType)"TEXT/HTML" Then
IsHearOK = True
Else
IsHearOK = False
End If
Else
IsHearOK = False
End If
Catch
MsgBox("连接异常,请检查网络!", , "提醒")
XMLObject = Nothing
End Try
End Function
调用ishearok(url)=true正常
用vb.net实现网络通信用 vb.net socket通信
Dim th As Threading.Thread
2Dim tcpl As System.Net.Sockets.TcpListener
3
4Private Sub Form1_Load()Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
5th = New System.Threading.Thread(New System.Threading.ThreadStart(AddressOf MyListen))
6th.Start()
7End Sub
8
9Public Sub SendMessage()Sub SendMessage(ByVal IP As String, ByVal SendMsg As String)
10Try
11If IP"" Then
12Dim tcpc As New System.Net.Sockets.TcpClient(IP, 5656)
13Dim tcpStream As Net.Sockets.NetworkStream = tcpc.GetStream
14Dim reqStream As New IO.StreamWriter(tcpStream)
15reqStream.Write(SendMsg)
16reqStream.Flush()
17tcpStream.Close()
18tcpc.Close()
19End If
20Catch ex As Exception
21MsgBox(ex.Message.ToString)
22End Try
23End Sub
24Private Sub MyListen()Sub MyListen()
25Try
26Dim ipAddress As System.Net.IPAddress = System.Net.Dns.Resolve(System.Net.Dns.GetHostName).AddressList(0)
27tcpl = New System.Net.Sockets.TcpListener(ipAddress, 5656)
28tcpl.Start()
29While True
30Dim s As System.Net.Sockets.Socket = tcpl.AcceptSocket()
31Dim MyBuffer(1024) As Byte
32Dim i As Integer
33i = s.Receive(MyBuffer)
34If i0 Then
35Dim lstrRec As String
36Dim j As Integer
37For j = 0 To i - 1
38TextBox1.Text= Chr(MyBuffer(j))","
39Next
40End If
41End While
42Catch ex As Exception
43MsgBox(ex.Message.ToString)
44End Try
45End Sub
46
47Private Sub Button1_Click()Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
48SendMessage("192.168.0.61", TextBox2.Text)
49End Sub
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