Check Internet Connection vb.net - vb.net

Question

I am trying to run some vb.net code that indicates if i'm connected to the internet
If My.Computer.Network.IsAvailable Then
MsgBox("Computer is connected.")
Else
MsgBox("Computer is not connected.")
End If
This works fine if I'm connecting to a WiFi signal that doesn't require a login. If I connect to a public WiFi signal that I'm required to login/pay and I execute the code before completing this step it still tells me I'm connected (in theory yes but without paying/logging in I'm not)
Any ideas how set this up?
Thanks

Answer 1

You could check for an internet connection by trying to read Google.com:
Public Shared Function CheckForInternetConnection() As Boolean
Try
Using client = New WebClient()
Using stream = client.OpenRead("http://www.google.com")
Return True
End Using
End Using
Catch
Return False
End Try
End Function
Taken from: Here

Answer 2

I use this
Public Function HaveInternetConnection() As Boolean
Try
Return My.Computer.Network.Ping("www.google.com")
Catch
Return False
End Try
End Function

Answer 3

I create this class to track internet connection changes. This class can check the stable internet connections also (stable means, that the connection not change during N second). The class raise events, if the connection changes.
Imports System.IO
Imports System.Runtime.InteropServices
Imports System.Runtime.InteropServices.ComTypes
Imports System.Text
Imports System.Collections.Generic
Imports System.Linq
Imports System.Net.NetworkInformation
Imports System.Net
Public Enum InternetConnectionState
Connected
Disconnected
End Enum
Public Class NetworkConnections
Implements IDisposable
Public Shared Property CheckHostName As String = "www.google.com"
Public Property ConnectionStableAfterSec As Integer = 10
Private MonitoringStarted As Boolean = False
Private StableCheckTimer As System.Threading.Timer
Private IsFirstCheck As Boolean = True
Private wConnectionIsStable As Boolean
Private PrevInternetConnectionState As InternetConnectionState = InternetConnectionState.Disconnected
Public Event InternetConnectionStateChanged(ByVal ConnectionState As InternetConnectionState)
Public Event InternetConnectionStableChanged(ByVal IsStable As Boolean, ByVal ConnectionState As InternetConnectionState)
Public Sub StartMonitoring()
If MonitoringStarted = False Then
AddHandler NetworkChange.NetworkAddressChanged, AddressOf NetworkAddressChanged
MonitoringStarted = True
NetworkAddressChanged(Me, Nothing)
End If
End Sub
Public Sub StopMonitoring()
If MonitoringStarted = True Then
Try
RemoveHandler NetworkChange.NetworkAddressChanged, AddressOf NetworkAddressChanged
Catch ex As Exception
End Try
MonitoringStarted = False
End If
End Sub
Public ReadOnly Property ConnectionIsStableNow As Boolean
Get
Return wConnectionIsStable
End Get
End Property
<DllImport("wininet.dll")> _
Private Shared Function InternetGetConnectedState(ByRef Description As Integer, ByVal ReservedValue As Integer) As Boolean
End Function
Private Shared Function IsInternetAvailable() As Boolean
Try
Dim ConnDesc As Integer
Dim conn As Boolean = InternetGetConnectedState(ConnDesc, 0)
Return conn
Catch
Return False
End Try
End Function
Private Shared Function IsInternetAvailableByDns() As Boolean
Try
Dim iheObj As IPHostEntry = Dns.GetHostEntry(CheckHostName)
Return True
Catch
Return False
End Try
End Function
Public Shared Function CheckInternetConnectionIsAvailable() As Boolean
Return IsInternetAvailable() And IsInternetAvailableByDns()
End Function
Private Sub NetworkAddressChanged(sender As Object, e As EventArgs)
wConnectionIsStable = False
StableCheckTimer = New System.Threading.Timer(AddressOf ElapsedAndStable, Nothing, New TimeSpan(0, 0, ConnectionStableAfterSec), New TimeSpan(1, 0, 0))
If IsFirstCheck Then
If CheckInternetConnectionIsAvailable() Then
PrevInternetConnectionState = InternetConnectionState.Connected
RaiseEvent InternetConnectionStateChanged(InternetConnectionState.Connected)
Else
PrevInternetConnectionState = InternetConnectionState.Disconnected
RaiseEvent InternetConnectionStateChanged(InternetConnectionState.Disconnected)
End If
IsFirstCheck = False
Else
If CheckInternetConnectionIsAvailable() Then
If PrevInternetConnectionState <> InternetConnectionState.Connected Then
PrevInternetConnectionState = InternetConnectionState.Connected
RaiseEvent InternetConnectionStateChanged(InternetConnectionState.Connected)
End If
Else
If PrevInternetConnectionState <> InternetConnectionState.Disconnected Then
PrevInternetConnectionState = InternetConnectionState.Disconnected
RaiseEvent InternetConnectionStateChanged(InternetConnectionState.Disconnected)
End If
End If
End If
End Sub
Private Sub ElapsedAndStable()
If wConnectionIsStable = False Then
wConnectionIsStable = True
Dim hasnet As Boolean = CheckInternetConnectionIsAvailable()
RaiseEvent InternetConnectionStableChanged(True, IIf(hasnet, InternetConnectionState.Connected, InternetConnectionState.Disconnected))
End If
End Sub
#Region "IDisposable Support"
Private disposedValue As Boolean ' To detect redundant calls
' IDisposable
Protected Overridable Sub Dispose(disposing As Boolean)
If Not Me.disposedValue Then
If disposing Then
Try
RemoveHandler NetworkChange.NetworkAddressChanged, AddressOf NetworkAddressChanged
Catch ex As Exception
End Try
End If
' TODO: free unmanaged resources (unmanaged objects) and override Finalize() below.
' TODO: set large fields to null.
End If
Me.disposedValue = True
End Sub
' TODO: override Finalize() only if Dispose(ByVal disposing As Boolean) above has code to free unmanaged resources.
'Protected Overrides Sub Finalize()
' ' Do not change this code. Put cleanup code in Dispose(ByVal disposing As Boolean) above.
' Dispose(False)
' MyBase.Finalize()
'End Sub
' This code added by Visual Basic to correctly implement the disposable pattern.
Public Sub Dispose() Implements IDisposable.Dispose
' Do not change this code. Put cleanup code in Dispose(disposing As Boolean) above.
Dispose(True)
GC.SuppressFinalize(Me)
End Sub
#End Region
End Class
Track changes on a form with 2 listbox. Important! The events are thread unsafe, that need to be handle with invoke method.
Imports System.Net.NetworkInformation
Imports System.Net
Public Class frmNetworkConnections
Private WithEvents conn As NetworkConnections
Delegate Sub AddToList1Callback(ByVal ConnectionState As InternetConnectionState, ByVal IsStable As Boolean)
Delegate Sub AddToList2Callback(ByVal ConnectionState As InternetConnectionState, ByVal IsStable As Boolean)
Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
conn = New NetworkConnections
End Sub
Sub AddToList1(ByVal ConnectionState As InternetConnectionState, ByVal IsStable As Boolean)
If Me.InvokeRequired = True Then
Dim d As New AddToList1Callback(AddressOf AddToList1)
Me.Invoke(d, ConnectionState, IsStable)
Else
ListBox1.Items.Add(Now & " - State: " & ConnectionState.ToString() & ", Stable: " & IsStable)
End If
End Sub
Sub AddToList2(ByVal ConnectionState As InternetConnectionState, ByVal IsStable As Boolean)
If Me.InvokeRequired = True Then
Dim d As New AddToList2Callback(AddressOf AddToList2)
Me.Invoke(d, ConnectionState, IsStable)
Else
ListBox1.Items.Add(Now & " - State: " & ConnectionState.ToString() & ", Stable: " & IsStable)
ListBox2.Items.Add(Now & " - State: " & ConnectionState.ToString() & ", Stable: " & IsStable)
End If
End Sub
Private Sub conn_InternetConnectionStableChanged(IsStable As Boolean, ConnectionState As InternetConnectionState) Handles conn.InternetConnectionStableChanged
AddToList2(ConnectionState, IsStable)
End Sub
Private Sub conn_InternetConnectionStateChanged(ConnectionState As InternetConnectionState) Handles conn.InternetConnectionStateChanged
AddToList1(ConnectionState, False)
End Sub
Private Sub btnStartMonitoring_Click(sender As Object, e As EventArgs) Handles btnStartMonitoring.Click
btnStopMonitoring.Enabled = True
btnStartMonitoring.Enabled = False
conn.StartMonitoring()
End Sub
Private Sub btnStopMonitoring_Click(sender As Object, e As EventArgs) Handles btnStopMonitoring.Click
btnStopMonitoring.Enabled = False
btnStartMonitoring.Enabled = True
conn.StopMonitoring()
End Sub
End Class
The result is:
I use the stable connection changes.
If you dont want to track changes, only check the connection, you can use the CheckInternetConnectionIsAvailable() shared function.

Answer 4

You could use the Ping class to try to reach a host in the Internet. In order not to wait too long, you should set a timeout when using Send.

Answer 5

A good way to check if the user is connected to the internet is
If My.Computer.Network.Ping("www.google.com") Then
MsgBox("Computer is connected to the internet.")
End If
You can also use this code, however it's slower
Public Shared Function CheckForInternetConnection() As Boolean
Try
Using client = New WebClient()
Using stream = client.OpenRead("http://www.google.com")
Return True
End Using
End Using
Catch
Return False
End Try
End Function

Answer 6

***** Best *****
The best Code For it, it not make any bug or Any slow.
Button Or Timer .. Etc
Try
If My.Computer.Network.Ping("www.google.com") Then
Label1.Text = "Internet Founded"
End If
Catch ex As Exception
'' Else ''
Label1.Text = "No internet Acess"
End Try
At least hope you gave me that
"Question Answer", it the best solution .Thanks.
(you can try it out)

Answer 7

Try
Dim client = New Net.WebClient
client.OpenRead("http://www.google.com")
Label21.Text = "Internet : Connected"
Catch
Label21.Text = "Internet : Disconnected"
End Try
Use this code in vb.net 100% solved, you can use this code form loading.

Answer 8

I am using this code and is working very well:
Public Function IsConnectedToInternet() As Boolean
If My.Computer.Network.IsAvailable Then
Try
Dim IPHost As IPHostEntry = Dns.GetHostEntry("www.google.com")
Return True
Catch
Return False
End Try
Else
Return False
End If
End Function

Answer 9

My.Computer.Network.Ping gave me problems so I used this function
Public Function fVerificaConnessioneInternet() As Boolean
Dim objPing As New System.Net.NetworkInformation.Ping
Try
Return If(objPing.Send("www.google.it").Status = IPStatus.Success, True, False)
Catch
Return False
End Try
End Function

Answer 10

or you could use this, a little better function to use. this should help you out if you need a c# version
http://www.guideushow.com/code-snippet/function-to-check-if-you-can-connect-to-the-internet-vb-net-c/
Public Function IsConnectionAvailable() As Boolean
' Returns True if connection is available
' Replace www.yoursite.com with a site that
' is guaranteed to be online - perhaps your
' corporate site, or microsoft.com
Dim objUrl As New System.Uri("http://www.google.com/")
' Setup WebRequest
Dim objWebReq As System.Net.WebRequest
objWebReq = System.Net.WebRequest.Create(objUrl)
objWebReq.Proxy = Nothing
Dim objResp As System.Net.WebResponse
Try
' Attempt to get response and return True
objResp = objWebReq.GetResponse
objResp.Close()
objWebReq = Nothing
Return True
Catch ex As Exception
' Error, exit and return False
objResp.Close()
objWebReq = Nothing
Return False
End Try
End Function