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Internet connectivityHi all,
How would one test for internet connectivity in VB.NET instead of using the Win32 API methods? Thanks, Adam WebRequest
T Adam Honek wrote: Show quoteHide quote >Hi all, > >How would one test for internet connectivity in VB.NET instead >of using the Win32 API methods? > >Thanks, >Adam > > > > What namespace is this?
..net?? Adam Show quoteHide quote "tomb" <t***@technetcenter.com> wrote in message news:bsa8g.39801$MM6.38564@bignews3.bellsouth.net... > WebRequest > > T > > Adam Honek wrote: > >>Hi all, >> >>How would one test for internet connectivity in VB.NET instead >>of using the Win32 API methods? >> >>Thanks, >>Adam >> >> Yes.
T Adam Honek wrote: Show quoteHide quote >What namespace is this? > >.net?? > >Adam > >"tomb" <t***@technetcenter.com> wrote in message >news:bsa8g.39801$MM6.38564@bignews3.bellsouth.net... > > >>WebRequest >> >>T >> >>Adam Honek wrote: >> >> >> >>>Hi all, >>> >>>How would one test for internet connectivity in VB.NET instead >>>of using the Win32 API methods? >>> >>>Thanks, >>>Adam >>> >>> >>> >>> > > > > Adam,
Pinging the first IP address outside your own environment is the way as is always used with or withouth a program. Cor Show quoteHide quote "Adam Honek" <AdamHo***@Webmaster2001.freeserve.co.uk> schreef in bericht news:eKyZRm7cGHA.4224@TK2MSFTNGP04.phx.gbl... > Hi all, > > How would one test for internet connectivity in VB.NET instead > of using the Win32 API methods? > > Thanks, > Adam > Yes I realise it's done via ICMP but I thought .NET has its own method
to check it without employing specialised techniques. Adam Show quoteHide quote "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> wrote in message news:uL$4Cw%23cGHA.3632@TK2MSFTNGP05.phx.gbl... > Adam, > > Pinging the first IP address outside your own environment is the way as is > always used with or withouth a program. > > Cor > > "Adam Honek" <AdamHo***@Webmaster2001.freeserve.co.uk> schreef in bericht > news:eKyZRm7cGHA.4224@TK2MSFTNGP04.phx.gbl... >> Hi all, >> >> How would one test for internet connectivity in VB.NET instead >> of using the Win32 API methods? >> >> Thanks, >> Adam >> > > On Tue, 9 May 2006 23:40:26 +0100, "Adam Honek"
<AdamHo***@Webmaster2001.freeserve.co.uk> wrote: >Hi all, If you want to know if a user is able to connect to the internet:> >How would one test for internet connectivity in VB.NET instead >of using the Win32 API methods? > >Thanks, >Adam > Dim isAvailable As Boolean isAvailable = My.Computer.Network.IsAvailable False = user has no current network connection of any kind True = user is connected to a network of some sort, but doesn't necessarily mean the internet is reachable. The companion statement to the above is: My.Computer.Network.NetworkAvailabilityChanged I usually do the above at startup in (MyApplicationEvents). Whether or not you use the above, each attempt to reach a server should use WebRequest and a Try/Catch Block where you are looking for a response of "OK" (200). If there is a problem, you would interpret the exception message which could be "No Connection", "Not Authorized", "Timeout" etc. There are WebRequest examples in the help file if you need them. Gene I've done what you suggest with WebRequest but it seems it's quite
a thread hog if it's called every second. Unless I put it in its own thread the UI thread is visibly interupted. Hmmm, maybe instead of pinging a website it pinged the NIC default IP gateway on one's PC, this would give better performance? Nice method though, quick and easy. Adam Show quoteHide quote "gene kelley" <o***@by.me> wrote in message news:vup262lfu6mcil36t5f605pvo3ptksdv8h@4ax.com... > On Tue, 9 May 2006 23:40:26 +0100, "Adam Honek" > <AdamHo***@Webmaster2001.freeserve.co.uk> wrote: > >>Hi all, >> >>How would one test for internet connectivity in VB.NET instead >>of using the Win32 API methods? >> >>Thanks, >>Adam >> > > If you want to know if a user is able to connect to the internet: > Dim isAvailable As Boolean > isAvailable = My.Computer.Network.IsAvailable > > False = user has no current network connection of any kind > True = user is connected to a network of some sort, but doesn't > necessarily mean the internet is reachable. > > The companion statement to the above is: > My.Computer.Network.NetworkAvailabilityChanged > > I usually do the above at startup in (MyApplicationEvents). > > Whether or not you use the above, each attempt to reach a server > should use WebRequest and a Try/Catch Block where you are looking for > a response of "OK" (200). If there is a problem, you would interpret > the exception message which could be "No Connection", "Not > Authorized", "Timeout" etc. > > There are WebRequest examples in the help file if you need them. > > Gene Adam Honek wrote:
> Hmmm, maybe instead of pinging a website it pinged the NIC default IP The default gateway is not necessarily outside the LAN. Neither is(are) the > gateway on one's PC, this would give better performance? DNS Server(s). E.g. C:\>ipconfig Windows IP Configuration Ethernet adapter Local Area Connection: IP Address. . . . . . . . . . . . : 192.168.123.14 Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.123.1 <-firewall appliance Andrew On Wed, 10 May 2006 08:30:38 +0100, "Adam Honek"
<AdamHo***@Webmaster2001.freeserve.co.uk> wrote: >I've done what you suggest with WebRequest but it seems it's quite I'm not sure what you mean by "called every second". Here is a snip>a thread hog if it's called every second. Unless I put it in its own thread >the UI thread is visibly interupted. > >Hmmm, maybe instead of pinging a website it pinged the NIC default IP >gateway on one's PC, this would give better performance? > >Nice method though, quick and easy. > >Adam > > of something I use. When the execution gets to this point, it's either a valid response, or there was an exception. On a broadband connection, here, from the time the URL is selected until the picture is completely displayed is generally 2-3 seconds. Exceptions other than timeout are virtually instaneous. (Code is used in a BackgroundWorker component, DoWork event) Try Dim request As HttpWebRequest = DirectCast(WebRequest.Create(PicLoc), HttpWebRequest) request.Timeout = 10000 Dim response As HttpWebResponse = DirectCast(request.GetResponse(), HttpWebResponse) If response.StatusDescription = "OK" Then RequestStatus = True End If response.Close() Catch ex As WebException Select Case ex.Status Case WebExceptionStatus.ConnectFailure Case WebExceptionStatus.Timeout Case WebExceptionStatus.ProtocolError Case Else end select End Try Gene Yup so yours is not running in the same time slice as the UI is. On mine
it's currently running this way hence there's this lag in moving the window or even clicking through the menus. That above is why I have a threading question posted in this newsgroup. Thanks, Adam Show quoteHide quote "gene kelley" <o***@by.me> wrote in message news:rda362ls7tm7bq5pktg7kremf1gaghodjo@4ax.com... > On Wed, 10 May 2006 08:30:38 +0100, "Adam Honek" > <AdamHo***@Webmaster2001.freeserve.co.uk> wrote: > >>I've done what you suggest with WebRequest but it seems it's quite >>a thread hog if it's called every second. Unless I put it in its own >>thread >>the UI thread is visibly interupted. >> >>Hmmm, maybe instead of pinging a website it pinged the NIC default IP >>gateway on one's PC, this would give better performance? >> >>Nice method though, quick and easy. >> >>Adam >> >> > > I'm not sure what you mean by "called every second". Here is a snip > of something I use. When the execution gets to this point, it's > either a valid response, or there was an exception. On a broadband > connection, here, from the time the URL is selected until the picture > is completely displayed is generally 2-3 seconds. Exceptions other > than timeout are virtually instaneous. > > (Code is used in a BackgroundWorker component, DoWork event) > > Try > Dim request As HttpWebRequest = > DirectCast(WebRequest.Create(PicLoc), HttpWebRequest) > request.Timeout = 10000 > Dim response As HttpWebResponse = > DirectCast(request.GetResponse(), HttpWebResponse) > If response.StatusDescription = "OK" Then > RequestStatus = True > End If > response.Close() > > Catch ex As WebException > > Select Case ex.Status > Case WebExceptionStatus.ConnectFailure > > Case WebExceptionStatus.Timeout > > Case WebExceptionStatus.ProtocolError > > Case Else > > end select > > End Try > > > Gene 
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