RE: SQL Err when WLAN conn is dropped and then restored. Help!
From: Flattron (danlee_73_at_hotmail.com)
Date: 08/17/04
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Date: Mon, 16 Aug 2004 19:23:03 -0700
I just read this article, Hope it will help you .
http://msdn.microsoft.com/mobility/windowsmobile/default.aspx?pull=/library/en-us/dnnetcomp/html/networkcomponent.asp
Regards!
DanLee
"Flattron" wrote:
> Hi,
> First ,Thanks for your quickly reply every much! :-) , My problem is
> slolved.This caused by the Windows XP service pack 2,There is firewall
> installed, so PPC can not access the SQL server in the PC.I just allow 1433
> port .all things is OK.
> As your question , I test in my PPC, When I successful connect database
> via wireless LAN,I unplug the wireless router 'power and wait a few minutes,
> plug the power of wireless router.I try connect with database again,It seem
> very slowly , but 5 second, It can connect with database.
> I believe, you should first make sure the PPC can get ip address which
> assign by the server.and then ,try to connect with server with Tcp/IP ,after
> everything is Ok, then connect with SqlServer, I believe it can be OK .
>
> Another advice is check the wireless setting in the PPC,some power saving
> setting maybe make wireless connection lose.
>
>
> Regards!
>
> Dan Lee
>
>
> "Callon Campbell" wrote:
>
> > Hi,
> > Your problem isn't the same as mine, but I'll do my best to help you out.
> > First of all I would change your program so that your SQL code is in stored
> > procedures. You can then test the sp in query analyzer to make sure it works.
> > You can also test the connection to the DB as your user ID.
> >
> > If all this works, then go and test with your PDA. I'm actually storing my
> > connection string in an XML config file on my PDA. But the value looks like
> > this:
> >
> > <configuration>
> > <appSettings>
> > <add key="ConnectionString" value="SERVER=192.168.1.100; DATABASE=MyDevDB;
> > USER ID=UserCE; PASSWORD=UserCE" />
> > </appSettings>
> > </configuration>
> >
> > In my code I do the following...
> >
> > public bool Function1(int locationID, ulong scannedUnitCode)
> >
> > {
> >
> > bool isSuccess = false;
> >
> >
> >
> > SqlConnection myConnection = new
> > SqlConnection(connection.ConnectionString);
> >
> >
> >
> > try
> >
> > {
> >
> > try
> >
> > {
> >
> > myConnection.Open();
> >
> >
> >
> > SqlCommand myCommand = new
> > SqlCommand("Some_StoredProc", myConnection);
> >
> > myCommand.CommandType =
> > CommandType.StoredProcedure;
> >
> >
> >
> > // Input Parameters
> >
> > SqlParameter paramLocationID =
> > myCommand.Parameters.Add("@LocationID", SqlDbType.Int);
> >
> > paramLocationID.Value = locationID;
> >
> >
> >
> > SqlParameter paramUnitCode =
> > myCommand.Parameters.Add("@UnitCode", SqlDbType.BigInt);
> >
> > paramUnitCode.Value = scannedUnitCode;
> >
> >
> >
> > // Output Parameter
> >
> > SqlParameter paramSuccess =
> > myCommand.Parameters.Add("@Success", SqlDbType.Bit);
> >
> > paramSuccess.Direction =
> > ParameterDirection.Output;
> >
> >
> >
> > try
> >
> > {
> >
> > myCommand.ExecuteNonQuery();
> >
> >
> >
> > isSuccess = bool.Parse(
> > paramSuccess.Value.ToString() );
> >
> > }
> >
> > catch (SqlException SQLE)
> >
> > {
> >
> > MessageBox.Show(SQLE.Message, "SQLError");
> >
> > }
> >
> > catch (Exception E)
> >
> > {
> >
> > MessageBox.Show(E.Message, "Error");
> >
> > }
> >
> > }
> >
> > catch (SqlException E)
> >
> > {
> >
> > MessageBox.Show(E.Message, "Error");
> >
> > }
> >
> > catch (Exception)
> >
> > {
> >
> > MessageBox.Show("Could not connect to the
> > Database. Check that your within wireless coverage and try again. Contact
> > tech support if this persists.", "Error");
> >
> > }
> >
> > }
> >
> > finally
> >
> > {
> >
> > myConnection.Close();
> >
> > }
> >
> >
> >
> > return isSuccess;
> >
> > }
> >
> >
> > I hope that helps. What I didn;t give you is the source to the XML, but this
> > can be easily obtained from the PocketVision sample app. The Connection class
> > simply has a property that only gets the connection string, which gets this
> > from the XML config.
> >
> > Anyway I hope that helps. The PPC has limited debugging support and I have
> > more times then I can remember stumped myself on data access because of
> > simple little things. That is why always test the user account and stored
> > proc with actual data in query analyzer before trying to test on actual
> > device/emulator.
> >
> > Cheers,
> > Callon
> >
> >
> > "Flattron" wrote:
> >
> > > My problem is I can connect SQL2000 via activeSync,but when I connect with
> > > wireless lan to SQL2000,there always happen SQLexception ,the server is not
> > > exist or can not access,Can you tell me how about the connection string ?I
> > > use sqlclient to connect DB
> > > The connection string is :
> > > "User ID=sa;Password=sa;Initial Catalog=Northwind;Server=192.168.1.100;Data
> > > Source=192.168.1.100"
> > > Is there any problem in the connection string ?
> > >
> > > The code as following :
> > >
> > > Dim scnnDB As SqlConnection
> > > Dim sReader As SqlDataReader
> > > Dim scmd As SqlCommand
> > >
> > > scnnDB = New SqlConnection(SQL_CONNECTION_STRING)
> > > scmd = New SqlCommand("INSERT INTO FeederID_Mobile
> > > VALUES('asdf','asdf',34,'Nil')", scnnDB)
> > > Try
> > > scnnDB.Open()
> > > scmd.ExecuteReader(CommandBehavior.CloseConnection)
> > > scnnDB.Close()
> > >
> > > "Callon Campbell" wrote:
> > >
> > > > Hi,
> > > >
> > > > I've developed a CF application that communicates to a backend SQL Server
> > > > 2000 DB over a WLAN. It is working fine, but occasionally the wireless PPC
> > > > looses it;s connection while the application is running. the next time a user
> > > > goes to hit the SQL DB (note: everytime a user goes to the SQL server, an
> > > > SqlConnection object is created and opened. I then close it when my data has
> > > > come back and I'm done using it), I get an error saying the DB doesn't exist.
> > > > If I quit the application and re-start it will work fine.
> > > >
> > > > What would be causing this problem (not the dropping of the WLAN, but the
> > > > error occuring AFTER the connection to the WLAN is restored and the user goes
> > > > to communicate to the DB)?
> > > >
> > > > Any help would be greatly appreciated. I can send sample code of one of my
> > > > functions for reference if need be. Just send me an email and I'll reply back.
> > > >
> > > > Thanks in advance
> > > >
> > > > Cheers,
> > > > Callon
- Next message: Ali: "Re: Getting the IP address of the desktop machine from the device"
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- In reply to: Flattron: "RE: SQL Err when WLAN conn is dropped and then restored. Help!"
- Next in thread: Callon Campbell: "RE: SQL Err when WLAN conn is dropped and then restored. Help!"
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