Checking Internet Connection constantly

Hay guys.

I've project where i wanna check if user is connected to internet if he isn't then form must close and another form should show up !

Problem i'm getting is i can't use check it constantly, even if i use while loop

Code:

---

 
' keep looping the following code until condition is wrong or until connection is made

        While IsConnectionAvailable() = False

            ' code goes here for when connection to hotflask can't be made.

                Form2.Show()


        End While

---

but here form 2 keep showing up and it crashes system, is there any simple way to do it !

thanks in advance.

I don't know specifically about internet connectivity but you can achieve this for general network connectivity (which may be the same thing effectively) by using Application Events. You can access these through the View Application Events button on the project settings page or you can just add your own class :

Code:

---

Namespace My

    ' The following events are available for MyApplication:
    '
    ' Startup: Raised when the application starts, before the startup form is created.
    ' Shutdown: Raised after all application forms are closed.  This event is not raised if the application terminates abnormally.
    ' UnhandledException: Raised if the application encounters an unhandled exception.
    ' StartupNextInstance: Raised when launching a single-instance application and the application is already active.
    ' NetworkAvailabilityChanged: Raised when the network connection is connected or disconnected.
    Partial Friend Class MyApplication

        Private Sub MyApplication_NetworkAvailabilityChanged(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.Devices.NetworkAvailableEventArgs) Handles Me.NetworkAvailabilityChanged
            If e.IsNetworkAvailable = False Then
                Dim MyForm As New Form2
                MyForm.Show()
            End If
        End Sub
    End Class

End Namespace

---

thanks for your effort.

but it doesn't work !!

When you say it doesn't work? You mean you specifically need to detect when internet connection is down, or it doesn't fire when you unplug/disable your network connection? Or it doesn't compile?

it doesn't work mean it doesn't work when disable my network, form 2 is not shown.
when i complie project without internet connection it doesn't work either

How did you add the code - was it by going through the project properties dialog? If not try it that way - it certainly works for me if I disable my wifi connection.

lol.. my bad .. i had wierd problem with my wifi. thanks

i've one more problem, my form takes too long to open and close after network disable/enable.

here is my code, pls guide me

---------------- my app event code ----------------

vb Code:

Public Function IsConnectionAvailable() As Boolean        ' Returns True if connection is available
 
            ' Replace [url]www.yoursite.com[/url] 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)
            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
 
                objWebReq = Nothing
                Return False
            End Try
 
        End Function
 
 
 
 
 
 
 
 
        Private Sub MyApplication_NetworkAvailabilityChanged(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.Devices.NetworkAvailableEventArgs) Handles Me.NetworkAvailabilityChanged
            If IsConnectionAvailable() = False Then
 
                Form2.Show()
                Form1.Close()
 
            ElseIf IsConnectionAvailable() = True Then
 
                Form1.Show()
                Form2.Close()
 
            End If
 
        End Sub

my startup form is form 2

---------------- form 2 code ----------------

vb Code:

If IsConnectionAvailable() = True Then
            Form1.Show()
            Me.Close()
        End If

thanks in advance

This ll help you

http://www.go4expert.com/forums/showthread.php?t=2557

The thing is, I would say that usually the network connection is not indicative of the internet connection. Many people are behind a router that is almost always connected, but the internet connection to that router might not be available.

The next best thing is to try and connect to a website like google (or some other website you know will be available).