vbnet网络 vbnet网络编程

用vb.net实现网络通信

用 vb.net socket通信

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Dim th As Threading.Thread

2 Dim tcpl As System.Net.Sockets.TcpListener

3

4 Private Sub Form1_Load()Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

5 th = New System.Threading.Thread(New System.Threading.ThreadStart(AddressOf MyListen))

6 th.Start()

7 End Sub

8

9 Public Sub SendMessage()Sub SendMessage(ByVal IP As String, ByVal SendMsg As String)

10 Try

11 If IP "" Then

12 Dim tcpc As New System.Net.Sockets.TcpClient(IP, 5656)

13 Dim tcpStream As Net.Sockets.NetworkStream = tcpc.GetStream

14 Dim reqStream As New IO.StreamWriter(tcpStream)

15 reqStream.Write(SendMsg)

16 reqStream.Flush()

17 tcpStream.Close()

18 tcpc.Close()

19 End If

20 Catch ex As Exception

21 MsgBox(ex.Message.ToString)

22 End Try

23 End Sub

24 Private Sub MyListen()Sub MyListen()

25 Try

26 Dim ipAddress As System.Net.IPAddress = System.Net.Dns.Resolve(System.Net.Dns.GetHostName).AddressList(0)

27 tcpl = New System.Net.Sockets.TcpListener(ipAddress, 5656)

28 tcpl.Start()

29 While True

30 Dim s As System.Net.Sockets.Socket = tcpl.AcceptSocket()

31 Dim MyBuffer(1024) As Byte

32 Dim i As Integer

33 i = s.Receive(MyBuffer)

34 If i 0 Then

35 Dim lstrRec As String

36 Dim j As Integer

37 For j = 0 To i - 1

38 TextBox1.Text += Chr(MyBuffer(j)) ","

39 Next

40 End If

41 End While

42 Catch ex As Exception

43 MsgBox(ex.Message.ToString)

44 End Try

45 End Sub

46

47 Private Sub Button1_Click()Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

48 SendMessage("192.168.0.61", TextBox2.Text)

49 End Sub

怎样用VB.NET进行网络编程？

都可以,可以用winsock,也可以自己重写SOCKET套接字.建议你如果工期紧,可以先用WINSOCK.当然最好是自己学用SOCKET套接字.这对未来开发网络通讯是很有帮助的.因为用WINSOCK有个毛病就是杀毒软件总会阻止

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

VB.NET如何判断电脑是否已连接到网络？

Microsoft.VisualBasic.Devices.Network.IsAvailable As Boolean

生成实例后可以通过此属性来获取是否联网的值，True代表已联网，False代表没有联网

Microsoft.VisualBasic.Devices.Network.NetworkAvailabilityChanged(ByVal Object, ByVal Microsoft.VisualBasic.Devices.NetworkAvailableEventArgs)

该事件是在电脑断开/连上互联网是引发的

其中：

e.IsNetworkAvailable

的功能同Microsoft.VisualBasic.Devices.Network.IsAvailable

实例:

Dim netListener As New Microsoft.VisualBasic.Devices.Network '生成实例

If netListener.IsAvailable = True Then

MsgBox("已联网")

Else

MsgBox("未联网")

End If

NetworkAvailabilityChanged实例：

WithEvents netListener As New Microsoft.VisualBasic.Devices.Network '生成实例

Private Sub OnNetworkChanged(ByVal Object, ByVal Microsoft.VisualBasic.Devices.NetworkAvailableEventArgs)Handles netListener.NetworkAvailabilityChanged

If e.IsNetworkAvailable = True Then

MsgBox("已联网")

Else

MsgBox("未联网")

End If

End Sub

VB.NET网络传输数组和字符串

解决方法：

1.字符串内容设置为定长，或者定义一个结束符（或字符串，如连续2个0xFF）附加在字符串尾部，程序以此方式先以文本方式读取字符串数据。

2.字符串内容也按照二进制方式发送。

3.在传输的字符串和二进制数据前附加N字节的标识字节，其中存储发送的字符串和二进制字符串长度。

方法很多。