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]....
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]...
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]....
[Code]...
Im clearly opening it there and its valid as i use the same connection to login with, anyone know the problem?
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?
View 1 RepliesI 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]
View 7 RepliesIn the first form I will load Tabels in the secound I want to open the DB Connection. I wrote a Class which enables me to open and close the connection
[Code]...
I am developing an application with VB using the MySQL Connector Net [URL]. Now each time I go to load data in to a datagridview or in to text boxes on a form, I have to provide something along the lines of:
Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
'Create connection to MySQL Database
Dim conn As New MySqlConnection
Dim myCommand As New MySqlCommand
conn.ConnectionString = MySQLGlobal
[Code] .....
I think it would be better to leave the connection open to the MySQL database while the application is in use. That way I can just continue to execute queries of inserting and updating, without having the delay of the application having to reconnect. Is there a way where I can create some sort of background task in the application that monitors every few seconds that the connection is still active, and if not it tries to reconnect until its reconnected? I am trying to have it so that then I can code it to just do queries, and when the connection breaks - it disables the form until it is reconnected.
Should I open a connection to MySQL at the load of my application and close it when you exit or should I open and close the connection only when I need to run queries?
View 1 Repliesi 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]....
...until an indeterminate amount of time passes and I get "The ProviderManifestToken '5' is different from '5.1' that was encountered earlier" error. Why is it encountering a '5' to begin with when I've only specified '5.1'?!!?The only way to get the error to stop is to reupload to edmx file (which has not changed at all), overwriting the previous one. At that point the application will happily chug along serving data to users until BAM the error occurs maybe a few hours later, sometimes days later and I'll have to start chasing my tail again.I've tried changing the ProviderManifestToken="5.1" to "MySQL", "6", "5" and the same situation will occur: works for a while then the error. As a bonus I only have this ONE edmx file in the vb.net webforms application so what is it getting confused bythe first few lines of my edmx file looks like:
<edmx:Edmx Version="1.0" xmlns:edmx="http://schemas.microsoft.com/ado/2007/06/edmx">
<edmx:Runtime>
<edmx:StorageModels>
[code].....
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]
View 14 RepliesHere 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]...
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
View 5 RepliesI 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]..........
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.
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"
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..
View 1 RepliesI'm connecting to my mysql server using ODBC in vb.net, the database is shared throughout the company because it is used in an accounting program (simply accounting), each user has their own account user/pass to login to the database. I have developped a program that uses the accounting database and combines it with other information, my problem is that at least once a day I get this error when I run my program: "(10061) ERROR [HY000] [MySQL][ODBC 3.51 Driver]Can't connect to MySQL server on"and the error persists for at least 4 hours, for some reason it starts to work again later on in the day.
View 1 Repliesi 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]....
Try If functionmode = "ADD" Then
[Code]...
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]...
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.
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]....
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
exitwithout()
[code].....
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]...
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.
View 5 Replieshow to properly connect to a MySQL database check if a login is valid.Basically i want someone to write me an example of how i connect to a MySQL database, check if username is correct, check if password is correct. If username and password is correct- it should return True as of boolean dim.
View 2 Replieshow to properly connect to a MySQL database check if a login is valid.Basically i want someone to write me an example of how i connect to a MySQL database, check if username is correct, check if password is correct. If username and password is correct- it should return True as of boolean dim.Otherwise it should return false.
View 1 RepliesI'm making a winforms app in vb.net that connects to a mysql database on my webserver to read and write data, this all works fine.But i have to allow the users ip to remote connect to the database.Is it possible to give everyone access to the database? The user account will not have all rights an the data isn't very important if it got lost.The user account and connection details are hard coded.
View 3 Replies