I know I'm missing something really simple here, but I'm trying to create a class that I can use to access the database in my program as this is obviously used a lot throught out the program and on different forms. I've used classes for other purposes and never had a problem but for what ever reason I can't seem to get this one to work.[code]...
View 1 RepliesI'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.
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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.
I am working on designing a SQL Server database connection class in VB.net 2005. The idea behind doing this will be so a developer can can call the class, pass it a stored procedure name along with the parameters, and get return values back (if any).
View 1 RepliesIs there a way to display the connection properties dialog for connection string browsing(for database) in run time?
As I want the user to be able to connect to various database using the GUI.
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
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i am using access database for my program. now i have connected to the database in MDI form of main exe, and ir also works, user can log in, it gets verified etc etc etc. now here is the problem, when i load a form from dll and try to use any sql query on that form, i get message, "database connection is not opened". so what i did was, i added the connect() (a function i designed to connect to database) in the load part of the dll's form, it made the trick, query's started to run, everything went fine, and when i reload the form i.e after closing the form, i load it again from MDI form, i get error, connection already open..
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I created a connection class that should return a datatables/datareaders etc to my webpages. I am worried that the connections won't be closed properly by using this class. Here is the class: [code]I am worried that once I go into production the connections won't be close properly and my site will fail. I am new to .net, is there anything wrong with the principal behind this class?
View 3 RepliesI want to create a class in vb.net that make the connection to database.Also I need the way to use this class inside forms. I need a code example of both the class and the form call
View 1 RepliesI'm using a OleDB connection to a access database. I'm entering a row into the database to set some user preferences. What i need to get is get back the row ID of the row I just entered. I'm more familiar with PHP and with PHP I use use this entry
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im making a class.vb which has a sql connection. The class.vb will be used by all forms/windows on the application. So whenever a form needs to access the database, it will call class.vb.
This is the code in class.vb:
Public Sub Openconn()
Dim myConnection As SqlConnection
Dim connstring As String = "Data Source=192.162;Initial Catalog=db1;User Id=sa;Password=1;"
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but it gives error: value of type sqlconnection cannot converted to array of Sqlconnection.I just want a method that's useful for opening the connection and that is also useful when asigning to a command object.
I tried to make my ODBC Connection within the class. here's my class code
Public Class Library
Public Function Seek(ByVal Connection As Odbc.OdbcConnection, ByVal TableName As String, ByVal Field As String, ByVal Index As Long)
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Here's my error: Unable to cast object of type 'System.Int32' to type 'System.Data.DataSet'. I am using VBdotNet2005
Trying to begin rewriting a VB6 application using .NET (as a Windows Forms app.) to get some practical coding experience.First hurdle is the best way to connect from VB.NET to typically various stored procedures in a SQL Server DB... I'm of course struggling a little along the way as well w/the difference in syntax and so forth, too.Anyone out there have an example you can point me to as far as typical blocks of code you use in calling to establish connectivity to SQL Server databases, populate SQLDataAdapter objects, etc?My assumption is that I need to create a connection object class and have everything in there and just call various methods of that connection object class whenever I need to connect to the database, retrieve data from stored procedures to populate fields on various screens of my app., close the connection to the database, etc.
View 4 RepliesIs there a (simple) way to connect a textbox, label etc. to a property in a class?I have a project with a complex series of dialogs to enter data into a list of a costum class describing an experiment with many parameters that are stored as properties (both simple variables such as strings and integers, but also more complex ones).I need both to be able to update the list of my experiment class, but also to go the other way to populate the dialogs from the class.It can of course be done outside the class and the dialogs in separate subroutines. This however, quicly becomes unmanagable and hard to maintain as the dialogs and experiment class is expanded with new elements.If there was a simple way to connect say a textbox or label in a dialog with the appropriate property holding the information it would make it much easier.
View 5 RepliesIn my application I have many different forms each use 3 different database. And right now I am placing the connection string in each form but when it is need to change I have to change in every form. Now what I want to store all connection string in a vb class and call them in every form. So that if I need to change I can do in that class. I have stored my connection string in database so even I don't want to connect to database again and again. I have some idea in which maybe a public class is used and some how I will call it on other forms.
View 2 RepliesIn my earlier project I was able to change the connection string during the app settings loaded event and it was successfully. When I try to do the same for a code library project, I am not getting the system.configuration.connectionstringsettings to work. Could you please tell if there is a work around for this, or else it is always better to write the sql code instead of depending on the adapters etc.
Additional information: Clients App is WPF with Vb. Database is SQL Server 2008 Code Lib would only be on server, slq connectiona and data retrieving and saving actions are stored in classes in code lib only. Code Lib would be used with WCF, wcf is used to share the classes only and classes have the data. WCF is hosted as a windows service on server used by NET.TCP
I am trying to copy a table in a database into another database on another connection in VB.NET, using OleDb. If they were on the same connection I would just use SELECT INTO, but they are not. I have two different OleDbConnection and cannot see an easy way to do this.
Right now I am attempting to just copy the database into a DataTable using an OleDbDataAdapter, and then loop through the DataTable and insert every record into the target database one at a time. This obviously takes a ton of time for the large DB I could potentially be dealing with, and I have to deal with escaping strings, null values, etc.
edit - just to make this more clear: I have two OleDbConnection objects, one is linked directly to a local .mdb file on my computer (JET). The other is linked to a database on our servers (SQLOLEDB). I am wanting to do this:
"SELECT * FROM fromDB INTO toDB"
But I can't because fromDB and toDB are on different connections, and the OleDbCommand object is only attached to one. The only way I can see how to do this is to connect to fromDB, copy it into a DataTable, connect to toDB, and copy all of the data in the DataTable row by row into toDB. I was wondering if there is an easier way to do this.
I am try to learn to use Mysql / MySql.Data.MySqlClientI did find sample how to connect to Mysql but I want to have it in Class or Module so I only call open database when I open the form
How can I fix this Name 'connStr' is not declared
CODE:
I have the following defined in my "Form1":So that I can access all my database functions anywhere in the main form (database connection is initialized via the "private sub new()" function in the DatabaseManager class.The works fine for all queries done in form1, however I have many other classes I'd like to be able to access the database from.Does anyone know how to access the initiated class in my example? Since right now it is initiated in the main form, if I try to access any functions inside any ot
View 4 RepliesYou can change the connection string at run-time like this. You make the connection string setting available for writing as a separate property inside the MySettings class:
Partial Friend NotInheritable Class MySettings
Public WriteOnly Property RunTimeConnectionString()
Set(ByVal value)
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Then, in some place when the application is being initialized (before using any table adapters of typed datasets), write something like:
My.Settings.RunTimeConnectionString = My.Settings.ProductionConnectionString
Where ProductionConnectionString is a simple String setting. It is a User Scope setting so every user can change it (by assigning a value to it, similar to the code above) and save it by calling My.Settings.Save()This code works well for connection strings which were initially created in the main project and stored in it's settings (= app.config file).
The connection string in the app.config actually has a longer name: MyApp.MySettings.MyConnectionString.When you have a connection string stored in the app.config in a class library project, and reference that project in the main project, the app.config files will somehow be merged, so the class library has it's settings.The thing that don't know how to do, is change a setting from the class library at run-time. I could copy the connection string setting from the class library to the main project's app.config. I must keep the same name, which looks something like: MyClassLibrary.My.MySettings.MyConnectionString.Can the same principle I showed above be somehow applied to this second connection string?
I am trying to change my windows application I made in vb.net that uses an access database. I do not know where this database will be stored at this time so my plan is to set the connection using code based off a text file that points to the location of the database. Here is the code I have but I know there is something wrong with my syntax because it putting "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|IWS.mdb" in both the data source and the database name.[code]...
View 14 Repliesi am an IT student and i want to understand very well how to program in visual basic.net and how to manipulate its connection to database since my project uses visual basic environment.
View 1 RepliesI'm just learning VB and would like to know: How do I create VB connection to an Access 2007 DB? I can use the DataGridView to view the table but can not create a connection to add records.
View 3 Replieswith the meaning of this snippet?
string conString =@"Provider=Microsoft.JET.OLEDB.4.0;" + @"data source=c:illing.mdb"; OleDbConnection conn = new OleDbConnection(conString); Conn.Open(); DataSet ds = new DataSet(); OleDbDataAdapter adapter =
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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
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I made program which connects sql database via WiFi network. I have timer wich every 10 minutes updates textbox information from database. If Network connection will be lose, i do not whant to get any error and after that lose data wich is in textbox, until sql database connection will not be. How can i check if connection exists and after that update data from database? Something like that:
Conn = New SqlConnection(ConnectionString)
Conn.Open() ' if connection is lost there gets error
If Conn.State = ConnectionState.Open Then ' But this does not works
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provide VB.net connection code to connect with sql server for adding,deleting and updating data.I'm new to .Net.I need to learn .VB.Please provide the code for this.Those who know the code please provide here.
View 2 RepliesPrivate Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim MyConnection As New OdbcConnection("Driver={MySQL ODBC 5.1
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I am trying to connect to access database in VB 2008 express. When I write the code like Dim cnTemp As ADODB.connection it gives error that ADODB is not defined.
View 3 RepliesI am using the visual studio 2008 but use the guide for 2oo5 .I wonder why the program show error after click the load button (btnload). I am following the http: [URL] and having problem with the 'Filling the DataSet'. Is it because of different version?
The code I use:
Public Class Form1
Private Sub Ordered_booksBindingNavigatorSaveItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Ordered_booksBindingNavigatorSaveItem.Click
Me.Validate()
Me.Ordered_booksBindingSource.EndEdit()
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I wrote a small application in witch I create a connection to a database. I'm new to this, so I followed the steps in MSDN help. I first created a link to the database with the "Datasource" of the Visual Studio environement. Then, in the code, I create instances of the dataset in the datasource and use a tableAdapter to register my changes in the database.
Now I want to allow the user of the application to specify the path of the DB file he wants to use. How can I do so? Do I still can use the datasource in the VS environment? I don't know where to start.