Error: Connection Must Be Valid And Open
Jul 5, 2010
I'm trying to insert data into a mysql database, I'm using xampp as well if thats of any relevance? I keep getting this error: Connection must be valid and open.
on cmd.ExecuteNonQuery()
I'm following my Microsoft Access application that I've also written as a reference and that works perfectly.' This is the code for inserting into an access database which works and is tryed and tested:
Imports System.Data.OleDb
Public Class frmEnterDetails
'text box variables
[code]....
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Mar 15, 2012
I am building a program for a small office and I have a little problem with the code so I thought it's better to post a topic before continiue.. I have search into google and a lot of forums about database connectivity and my problem is simillar to other but a lot of things differs.The error that I get is on executeNoQuery() and it's called {"Connection must be valid and open."} Well a lot of things may related to about that.At least now from my re-search I covered all the filds of the problem and still not fixed. So please check my code for (Add new customer) button and let me know where I have mess up.
[Code]...
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Mar 29, 2011
[Code]...
Im clearly opening it there and its valid as i use the same connection to login with, anyone know the problem?
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Sep 15, 2011
I'm trying to make a login from in vb2010 as a windows application but I keep getting a error message saying "Connection must be valid and open"My code for the sign in button is:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdok.Click
' Adminstration login
' Add code here for secure admin
[code]....
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Jan 15, 2012
I am creating a login form together with sql as may databse but when i run may program an error occur at "myData = myCommand.ExecuteReader()" stating that "Connection must be valid and open" what should i do on that to make it fix? [code]
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Aug 3, 2011
i have an application. which is executed after every 5 mins. i have an open connection but it gives me the following error:
ExecuteScalar requires an open and available Connection. The connection's current state is closed.
my code is something like this. I have shown where all i am using ExceuteScalar()
Sub Main()
Try
connection.open()
cmd.ExecuteScalar()
[code]....
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May 22, 2012
Here is code that I'm running. I am new to vb.net and setup a MySQL server 5.5 and I just want to insert a name into the database that is located on my computer. I can connect to it through the Server Explorer in Visual Studio 2010 premium, but when I try connecting in the program it gets to the cmd.ExecuteNonQuery() method and says that InvalidOperationException was unhandled. also I have the Connector/net version 6.45 installed
[code]...
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Jul 9, 2009
I was wondering if its possible for VB to display all available COM ports that are open. he reason that I ask this is because this program will be run on various computers where the COM port will not always be the same. I have a text box now that the user can choose which com number he/she wants but if the wrong one is entered, the program crashes rather than displaying an error message. It would also be nice for the system to show which available com numbers there are
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Jul 17, 2009
I keeping getting an error.Seems to be the connection string.Error happens at connection.Open()
Error Message:Cannot open database "C:UsersJEREDocumentsVisual Studio 2008ProjectsBaseball2009Baseball2009DatabaseBaseball2009.sd"
requested by the login. The login failed. Login failed for user 'JERE-PCJERE'.
Imports System.Data.SqlClient
Public Class Field
Private Sub Field_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load[code]..........
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Jun 19, 2012
Currently I'm working on a piece of code that involves using the Crystal Reports Viewer to export .RPT files to PDF. My problem is that the code works on literally everything except the website I'm planning to eventually put it on.
When placed on the website it throws back the error "Failed to open the connection." which I believe is connected to the SQL Server connection that's formed in order to read data for the report itself.
The code itself is solid and works when used in a separate console application I built to test it whether said code is run on my local machine or on the server itself. It even runs when I test the website in Visual Studio's virtual host.
I've narrowed it down to being some sort of permissions issue, but I am not knowledgeable enough in the various permissions settings to figure out which ones specifically apply to this situation. It's worth mentioning that other pages on the website are directly connecting to the same database, but they are doing so directly through Linq instead of going through the Crystal Report Viewer.
So does anybody know which settings I need to modify in order to fix the connection error.An added note: One of the other suggestions is to make sure there's an ODBC DNS in place that matches the one being used by the code. I have created such a DNS already.
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Jun 29, 2011
I'm creating a tool that will query Excel and intialize the default settings for the site's Cad Software.I want 2-20 users to be able to simultaneously query excel. Currently I have the spreadsheet open on one computer and the other test machine gives me this error.
GetOleDbSchema Table Require an open and available connection. The connections state is closed.
I could use some help on the code design. Should I use Datareader instead....Does that have less permissions issues? Or do I need to open up the oledbconnection in a different manner?
Private Const cPageData = "PageData"
Private Const cPrinterData = "PrinterData"
Private Const cSupportData = "SupportData"
Private Const cUserData = "UserData"
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Aug 2, 2011
I have o problem on my codes sqldr = sqlcmd.ExecuteReader when i debug the program error says ExecuteReader requires an open and available Connection. The connection's current state is closed. i dont know what its means that error..
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Nov 30, 2008
i make a class and when i call on form then that error occurs "ExecuteNonQuery requires an open and available connection, the connection Current stat is close "
Class Code isImports System.Data.SqlClientImports System.DataImports System.StringPublic Class DatabaseKits Dim Cn As New SqlClient.SqlConnection Public Function BuildConnection() As Boolean Try Cn.ConnectionString = "Persist Security Info=False;Integrated Security=True;Trusted_Connection=Yes;database=BizAimsPro2008;server=Server-2k3s" BuildConnection =
[code]....
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Dec 19, 2011
Try If functionmode = "ADD" Then
[Code]...
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Jul 5, 2011
I got this error..The connection was not closed. The connection's current state is open.
This is coding to add data in Ms access in vb...
Imports System.Data.OleDb Public Class Form1
[Code]...
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May 20, 2010
I'm developing a device app in VB.net that will access a SQL Server database. I need to establish a connection when the app is launched, and keep the connection open until the app is closed. I've done the following:In the Master Module:
Public CNN
As SqlConnection
In the Main menu form load:
CNN =
New SqlConnection(sqlConnString)
CNN.Open()
Then when I want to read from the database:
Dim sqlDR
As SqlDataReader
SQL = "SELECT Name FROM Table"
[code]....
When I run the same code without the global CNN, but rather dim the connection inside the Select function, all works well.
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Mar 11, 2010
I'm trying to insert a new records into database, one of those records is a "datetime"...when I type a wrong date, and try to insert those values into database, i get an error (about wrong typed date etc.)...ok, that's fine, things need to work that way. But here comes the problem, I correct the date, and then try to insert values again...here I get an error from the post title. And this doesn't work until I close that form and run it again...here's part of my code:
Dim cvLicence As New SQL
Try
cvLicence.upis("INSERT INTO blabla (itsnotimportant) VALUES ('something')")
MsgBox("everything's fine", MsgBoxStyle.Information)
[code]....
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Jun 12, 2011
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
exitwithout()
[code].....
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Jun 4, 2011
I have an VB.NET application. This Application is permanently resident in memory and minimized to the tray area because we use it very often. The problem comes in when we VPN into a client's site. These VPN connections trash all other network connections to and from our machines.Then every time my VB.NET application refreshes its database, errors start occurring, because the machine has lost connectivity to the SQL server, however, these are not at the connection level, but only when the reader attempts to read.
I am checking for connection.open, but because of the SQL connection pooling, I just get a previous connection that was valid before the network was cut. Is there anyway to check if an actual SQL connection is valid, prior to re-issuing a connection from the pool?[code]...
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Oct 21, 2009
In my program, I have a timer with a inteval set to 1000ms. The timer is executing a MySQL-command, and right now I'm opening and closing the connection each time.
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Feb 19, 2012
MVC3, VB.NET, using EF. I am working on coding up a simple function to handle checking for a valid MySQL connection. If the connection fails the test it will use the secondary server connection. This is required because our hosting provider does not provide failover or redundant MySQL servers. The problem is I tried to use a simple try catch method in the HomeController. This fails early because the Entity Framework is looking the connection that was set up when I set it up... Is there anyway to control that connection dynamically?
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Mar 15, 2009
I have a simple scraper. It works on some websites, but on some there is this Error:
Quote:
IOException was unhandled Unable to read data from the transport connection: The connection was closed
It is occuring at "Dim htmlresults As String = Urlcontents.ReadToEnd()".
'Create the HttpWebRequest object
Dim req As HttpWebRequest = WebRequest.Create(URL)
'Set the timeout to 1 second (or 1,000 milliseconds)
req.Timeout = 10000
[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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May 5, 2012
I am having a problem that I keep getting the following error when I try to run my program.I am trying to make a circle the size of the value of FrameSize.A first chance exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll
This is the details of the error:
System.InvalidOperationException was unhandled
Message=An error occurred creating the form. See Exception.InnerException for details. The error is: Cross-thread operation not valid: Control '' accessed from a thread other than the thread it was created on.
Source=DreamCatcher[code]......
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Aug 18, 2009
I have a program that sends some data on a networkstream through a tcp connection.
[Code]...
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Nov 23, 2011
I have a .mdf file that I open through an Open Dialog Box and use in a ConnectionStringBuilder (where I have the user instance set to True). Later, in one of my button clicks, I try to open the connection (connection.Open()). It then gives me an error as follows: "Generating user instances in SQL Server is disabled. Use sp_configure 'user instances enabled' to generate user instances."
Here is my code:
Option Strict On
Imports System.Data.SqlClient
Public Class frmMain
[code]....
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May 12, 2005
I am currently working on a login page using vb.net. I would like to know how to make connection to an access database and verify that the user logged in is a valid user
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Jan 14, 2011
I'm trying to connect to a database and keep the connection open for any amount of user activity/queries within the database. Currently I have a connection that opens and closes for any query (save, update, etc...) which requires the logon process to the back-end every time the user saves etc... Is there a way to simply connect and leave the connection open so there won't be a lag time when running the query due to the logon process? This is what I'm using:
Private sConStrFormat As String = "Provider=TDOLEDB;Data Source=TDDEV;Persist Security Info=True;User ID={0};Password={1};Default Database=bcpm_ddbo;Session Mode=ANSI;"
[Code].....
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Jan 17, 2009
i want to know how to open a connection to database from vb.net
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Sep 18, 2010
when I attempt to make the connection through a VB.Net with window application, I am getting the following error: ERROR [28000]
My connection string is
HTML
<connectionStrings>
<add name="MyConnection" connectionString="Driver=PostgreSQL ANSI;Server=10.146.152.23;Port=5432;Database=pacs;Uid=postgres;Pwd=postgres;" />
</connectionStrings>
<system.diagnostics>
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