.NET Closing Connection To SQL Server?
May 30, 2010
I have many Listviews in my Form and Im retrieving stored procedures to populates my Listviews. Is it necassary to close the connection to SQL Server once I have finished populating my Listviews?The angle which im coming from is that every 30 seconds or so I need to re-populate my Listviews with the latest cut of data from SQL Server therefor Im probably going to slow down my application if it has to connect to SQL Server every 30 seconds to get the latest cut of data... instead of keeping the connection to the SQL Server Stored Procedure live so that I can use some sort of method to refresh the data?
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Sep 7, 2011
When it comes to database connections what is the difference between closing a connection & disposing a connection? I'm hoping to gain a more technical understanding of what happens when each is called & the effect on the database.
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Sep 3, 2009
I'm connecting to an ftp server in my .net application. After I send the file and try to close the connection, I'm getting an error. I'm trying to send the Quit command to the FTP server but getting no reply. I'm not sure what I'm doing wrong. I call this method: [code] Do you think something is wrong with the code of could it be a problem with the ftp server?
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Sep 13, 2009
Is it necessary to close the connection of a tcplistener or tcpclient after every message received, or is it possible to close it at a later time while it continues to receive data? Is there any major security issue with leaving it open and listening? I know trojans tend to open a listener and leave it open, will my program be detected as such? Its just a simple chat program....
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Feb 17, 2010
I'm writing a Windows form application in VS 2008. In the application I need to move among several SQL express databases (.mdf). I'm using the following commands to change the connection:
Me.MyTableAdapter.Connection.Close()
Me. MyTableAdapter.Connection.ConnectionString = "NewString"
Me. MyTableAdapter.Connection.Open()
I can see the form is showing data from the 2nd database. However, When I tried copying the 1st database (for a Save as function I'd like to implement), I got a system error saying "Cannot copy MdfFile: It is being used by another person or program.". Actually, I found all the visited databases were "being used" untill I closed my application. How do I break the connection completely?
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Nov 19, 2011
I get this error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '*' at line 1 [Code]
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Mar 30, 2010
I've got a fairly large VB.NET (3.5) project that makes a lot of database calls. So I created a namespace/class just to handle those fuctions. The idea was that this single point of entry into the database would give more control over validating input from users.
So my class looks something like this. (I've chopped some code out for readability, it works just fine except for all the open connections.
[Code]...
So I can close the data reader, but how do I reach back to that original database class and close the connection. If I close it in that original class it will bomb when I try to loop through the data reader the in calling class.I'm sure this is probably pretty obvious but I'm fried from the keyboard.
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Dec 9, 2009
When connecting to a Sybase ASE database via ODBC using the code below, I'll occasionally get a '[IM006] [Microsoft][ODBC Driver Manager] Driver's SQLSetConnectAttr failed' error. this be caused by my code? I read here that I should be using the 'With' statement instead, but I don't understand how that would affect this.
[Code]...
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Aug 19, 2010
After running the following sub (VS debugger), I try to detach the database in SSMS, but it shows the connection open still and won't let me detach. If I close program in debugger, the database shows no connections. I check the dataadapter's connection in the finally block and is shows closed. What gives
Private Function ClientMasterDBFiles(ByVal MasterClientDBConnection As String, ByVal DBName As String) As DataTable
[Code]...
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Mar 19, 2012
Finally starting some coding in VB.Net, I notice over the years, that we can say (in VB6)
Code: Dim MyForm_Stock as NEW frmStock
in the same session, being able to open, say 3 Stock Forms at the same time and maintain details independently of each of the other forms. Also am I able to maintain separate Database connections and the same table being opened and updated independently of each other by each separate form. What is actually taking place in terms of memory being used by each process? My ultimate goal is to be able to have ONE Module with all the possible data Connection and Recordset Opening and closing options, which I have failed miserably to do in my VB6 experience. Data access is an obvious module based set of subroutines. Others could be Date routines eg, Week Number of the year, Days Diff, Days to, etc. [Code]
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May 14, 2010
This will happen at random, and I can always just catch the error and re-establish connection to the server, but I am confused as to why. When doing lots of inserting into the sql server, I only establish one connection that is public, instead of many little connections. I had my doubts on a public sql connection, but it's been running great, and I've seen no problems until this morning. Again, this random moment I hit an error that stated, sql connection state is broken. Is it bad practice to just accept this error, and when it happens, re-establish the connection?
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Nov 28, 2009
This emailing code wont seem to work in my program. I get an exception "The SMTP server requires a secure connection or the client was not authenticated. The server response was 5.5.1 authentication required."
Imports System.Net.Mail
Public Class emailStudent
Private Sub sendEmailButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles sendEmailButton.Click
SendMail()
[code]....
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Aug 18, 2009
I have simple code that connects to Sql database... (well it doesn't)
VB
Dim objConn As New SqlConnection("Server=localhost;uid=***;pwd=***;database=***")
objConn.Open()
ERROR MESSAGE:A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)But looks like something is wrong with "localhost" thing. Any help? Where can I get name of (my) server?
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Feb 29, 2012
I am tring to make the below application work with SQL Server 2005 Database Currently it works for test.mdb, which is in the same folder with the application. How shoud I modify the MapPath to work with SQL Server.
[Code]...
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Jan 27, 2011
I have a simple tcpclient/server messenger running. Everything works great, except for when a client exits the software. When someone exits, is crashes the server with various exceptions and the server has to be restarted, as well as the clients. What I am looking for is a way to properly "log out" a client BUT leave any other connected client on so that is no break in the chat. Then the person that logged out or a new person can join back in whenever they choose.
CLIENT
''CHAT SERVICE
Dim clientSocket As New System.Net.Sockets.TcpClient()
Dim serverStream As NetworkStream
Dim readData As String
Dim infiniteCounter As Integer
[Code] .....
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Aug 13, 2010
I am trying to do something fairly simple.. allow my user to import thier data from Excel into SQL Server, where it can be used by the application.To do this, I'm using the fairly simple code that is common everywhere I look:
strFilePath = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fdlgFileOpen.FileName + ";Extended Properties=Excel 8.0"
connExcel = New OleDbConnection(strFilePath)
connExcel.Open()
[Code]...
Now, on my development computer this code works perfectly. The data imports, and I can go on my merry way.
On the TEST computer, this code throws the error: "ODBC -- Connection to {SQL Server} servernamesqlservername failed." This seems very odd to me, because I'm using exactly the same SQL Server and database to interact with the application, and all the other screens in the application work perfectly. The test computer CAN connect to this SQL Server, but it keeps throwing this error whenever I try import data from Excel.I've tried everything I can think of - using the server's IP address instead of the server name, sending the SQL Server administrator data along with the request, taking out the Trusted_Connection=Yes... nothing works. What is going on here? How can this code work fine on my computer, and hiccup on another?
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May 3, 2010
Form1 is a mdi container. It has a bunch of forms that can load inside of it as mdi children. If I close each open form inside the form1, and then click the red X at the top right, application exits fine.If I click the red X without closing the forms inside I get: An unhandled exception of type 'System.CannotUnloadAppDomainException' occurred in mscorlib.dll
Additional information: Error while unloading appdomain. (Exception from HRESULT: 0x80131015) However I can break from it. How do I get the application to not show that error? What must I do to fix those inside forms or close when the red x is clicked?
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Jun 4, 2010
Dim frm As Form
For Each frm In Forms
Set frm = Nothing
Next frm
The above code is what I used in VB6 to close all forms associated with my programs before my program closed. I have been searching for information on how to make sure all forms are closed when closing a VB2008 program.
I have seen info on using the Project Property Shutdown mode When startup form closes and I currently have this set.
Is this all that is really necessary? Will the garbage disposal close everything else to free up RAM?
Also, if I have several forms open and want to close all from the main form without closing each one individually, what is the best approach? Is there a collection like in VB6, go through the collection, compare it to the name of the main form and close it if it is not the main form?
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Jun 21, 2010
i started programming with .NET (i have express edition) and wanted to make a connection to an SQL Server..previously i had .net 2005 - i started having the issue there - i unistalled it, n installed visual studio 2008. I have installed SQL Compact that came with the .net 2008, and besides it SQL Server 2000.When I try to make a connection to the SQL Server, if server is running I have to stop it and then choose the DB i want to use. (if its running wont let me choose any DB). Then, when i select the DB i need, Im getting this error:
"The instruction CREATE FILE fount SO error 5 (failed to retrieve text for this error.Reason:15105) while trying to open or creating the fysichal file : -path- to northwnd_log.ldf. Cant open the new database -path to northwnd.mdf. CREATE DATABASE discarded.Error while trying to attach a DB automatically named for archive -path to northwnd.mdf. There already exists a database with the same name, cant open the specified file or it is in a shared UNC resourse.File activation error. File name -path to northwnd_log.ldf- might be wrong"And when i try to connect with the SQL compact edition that came installed with the visual studio, im getting this error:"Can not allow access to the file in DB [File name = path to northwind.sdf]"
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Mar 14, 2012
why i'm getting the following error from the code below:
Error Type:
Active Server Pages, ASP 0221 (0x80004005)
The specified 'Import Namespace="System.Data.OleDb" ' option is unknown or invalid.
/default.asp, line 6
[Code].....
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Sep 18, 2011
I've been trying to make a login system for my application. Which seems to work, but when I try to connect to the database itself, it won't work. I used this code to check the exception:
Catch myex As MySqlException
MsgBox(myex.Message)
That gives this exception:
"Acces denied for user '[my db user]'@'[My IP-Address]' (Using Password: YES)"
The code I use for the connection is:
Dim Connection As New MySqlConnection("server=[The SERVER IP]; user id=[DATABASE USER]; password=[DB USER PW]; port=3306; database=[DB NAME]; pooling=false")
Connection.Open()
MsgBox("Connected")
As you can see, I've tried to change the 'server' part, but it won't affect anything. It will just say my ip address (localhost, I assume) in the exception. Telling me that it couldn't connect to it. Which is not even what I'm wanting to do.
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Nov 15, 2011
I'm using Visual Studio 2005 and SQL Server 2000 for my vb.net desktop application..I'm having a SQL Server exception saying that "connection can't be established to the server.hen connecting to SQL Server 2005 this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. Also showing
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Apr 19, 2012
I have installed sql server 2005 in my machine which is installed vb.net 2008. I want my machine to distribute the database to the clients and make it as server.I don't have that much knowledge of how to overcome this issue as i am awfully naive about it.Let me start it here:I have got an application in vb.net...at first i was using ms access database 2007. then decided to switch on to the sql server since i want to distribute the database to the clients who are going to use my application.When i installed the sql server, i imported my access db files onto sql server database. i enabled tcp/ip as enable in the sql server network Configuration. i want use sql server windows authentication as my default user account of my system for the sake to simplify the issue.
Hence, i connected the sql server into the vb.net through the "add new data source".am done with that...the problem is how do i assign the connection string to the vb.net? Or how do i include a connection string in vb.net which tells every other computer that the database data source is in my computer so that every computer can automatically check it in the network.Where exactly shall i put the connection string...as far as my knowledge is concerned for access database, you can easily identify your connection string in project /properties/settings...it goes here and you put your database in any where.And what is the best connection string do i need for sql server 2005..computers are running windows xp.
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Feb 26, 2009
I making a connection through word 2003 VBA to SQL server 2005 using the following codeDim cn As ADODB.ConnectionSet cn = New Connectioncn.ConnectionString = "Provider=SQLNCLI;Server=LEXAE29150SQLEXPRESS;" & _"Database=MCarter.mdf;Integrated Security=SSPI;"cn.openetc.cn.close.All runs fine up to cn.open.I then get the message error 'Cannot open database "MC.dbf" request by the login. The Login failed'.Tryed websearching but no succes. Been on it a week and the boss is doing his nut. I'm lost and unsure what wrong.The SQL server is set for windows authenticity and SOL Server login.In the MC database under security users my user name (Login) is their and setup as owner and sysadmin.SQLServer is running on the same machine as the word.dot.
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Oct 6, 2011
I using vb.net 2010 and sql server management express 2008. bu I little confused what is wrong with the code for connect sql and vb.net
[Code]...
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Nov 26, 2008
how to use conection with vb.net 2005 and ms access and also sql server
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Aug 12, 2010
I am wondering if it is possible to perform some SQL command on a datatable. I currently have an application which reads in an excel spread sheet using the excel COM, and stores the data in a object array. The Object array is then used to create a datatable based on user specifications. I have added a number of checked list boxes which are populated with the column names and row number. The user can select what rows and columns that want to see, and the datatable is recreated to their needs and displayed in a datagridview.
Although at the moment the program is fairly simple in design, but I plan to add a bit to it. I am now wondering if you can use an SQL statement to extract a set of data from a pre-existing datatable. Most examples I have seen involve a connection to an SQL server,
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Mar 20, 2012
I have SQL Server 2008 setup to remote connection. and it works perfect. I can access it from public IP address. [code]...
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Feb 26, 2012
I'm trying to run this code, but it displays the error "overload resolution failed".
[code...]
Here is the full error:[code...]
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Mar 19, 2012
I'm creating a program in VB.Net that heavily interacts with 2 large MSSQL databases. I do not know a ton of vb and I'm fairly new, but I would assume just having the connection strings in the code and releasing the program it would be quite easy for someone to reverse the program and get my connection info? correct me if I'm wrong. My question is I'm wondering if there is a safer way to use a connection string in my program. Would I just have to encrypt my app? Create a module or dll?
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