Visual Basic

<br />
Private Declare Function IsNetworkAlive Lib "SENSAPI.DLL" (ByRef lpdwFlags As Long) As Long<br />
<br />
Private Const NETWORK_ALIVE_LAN = &H1 ' LAN connection<br />
Private Const NETWORK_ALIVE_WAN = &H2 ' RAS connection(for internet)<br />
<br />
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click<br />
 Dim llReturn As Long<br />
<br />
 If IsNetworkAlive(llReturn) = 0 Then<br />
  MessageBox.Show("Your system is not connected!")<br />
 Else<br />
  If (llReturn And NETWORK_ALIVE_LAN) = NETWORK_ALIVE_LAN Then<br />
   MessageBox.Show("Your system is connected to the LAN" + _<br />
                   " (may be over router to internet too)!")<br />
  End If<br />
  If (llReturn And NETWORK_ALIVE_WAN) = NETWORK_ALIVE_WAN Then<br />
   MessageBox.Show("Your system is connected to the WAN by any" + _<br />
                   " kind of modem direct connected to you system!")<br />
  End If<br />
 End If<br />
End Sub<br />

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

    If My.Computer.Network.IsAvailable = True Then
        lblConnectedStatus.Text = "Connected"
    Else
        lblConnectedStatus.Text = "Not Connected"
    End If

End Sub

Private Sub MyApplication_NetworkAvailabilityChanged(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.Devices.NetworkAvailableEventArgs) Handles Me.NetworkAvailabilityChanged

    If e.IsNetworkAvailable = True Then

        My.Forms.Form1.lblConnectedStatus.Text = "CONNECTED"

    Else

        My.Forms.Form1.lblConnectedStatus.Text = "Not Connected"

    End If

End Sub