How To Draw A Connection
Jun 1, 2012
I have a problem with my project. (attached file).When I click on the "computer", I get a computer on the screen. Suppose on the screen, i have 2 computers. (they can be moved) Now I want that:
1. When I click on the "Connection" button and choose the 2 computers, the connection is drawing. If still want to draw a connection, I have to click on the "Connection", choose the 2 computers again.
2. When I move the computer's location, "connection" will not be lost.
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Jun 1, 2012
I have a problem with my project. (attached file).When I click on the "computer", I get a computer on the screen. Suppose on the screen, i have 2 computers. (they can be moved)
Now I want that:
1. When I click on the "Connection" button and choose the 2 computers, the connection is drawing. If still want to draw a connection, I have to click on the "Connection", choose the 2 computers again.
2. When I move the computer's location, "connection" will not be lost.
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Apr 26, 2010
I need to get the DataGridView to perform the way it should perform. I'm new to the .NET environment, but I learn fairly quickly. However, I find it difficult to decipher themassive black box of the DataGridView control enough to make it do anything other than what it already does--Draw very slowly.
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Oct 14, 2011
I have a form that uses a button to draw a line and a second button to draw a rectangle. I have a third button to clear the form but can't find a code example to code the Clear button.
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Aug 25, 2009
How do I assign a My.Settings.Item connection string to cmd.Connection connection string value?
Dim cmd As New SqlCommand()
cmd.Connection = My.Settings.Item("csStaffHoursWorked")
cmd.CommandType = CommandType.StoredProcedure
cmd.CommandText = "spSaveDeltekImport"
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Jul 2, 2009
I have to draw a bar graph in my vb.net program. I used AxMSChart to create a graph. Everything has gone fine but when i published this and run on Vista PC, all form was good except my form includes MSChart. It says class not registered.So i have to draw a graph except MSChart tool.
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Feb 5, 2010
Is 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.
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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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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 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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Jun 21, 2010
I am attempting to write a program that will disable the Local Area Connection while leaving the Wireless connection enabled. My company is using net-books in our stores to demo air-cards and we need to keep them off of the LAN. I'm new to VB and VB.net, and it's been a while since I did any type of programming. I've gathered some code that others have posted in forums and tutorials and I'm working through a tutorial book, but I finally believe that I am stuck.
[Code]...
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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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May 17, 2012
I am connecting to a data stream that pushes data continuously and when I tried to set up a network stream I just could not connect and kept getting the 'not found' error. I used the httpwebrequest with webrequest.keepalive = true and started to consume the data by reading into a buffer and then appending to a stringbuilder. Once the stringbuilder reaches max size I flush it to a text file. The problem is that I get disconnected from the data stream because I am not reading the data fast enough. I need to keep the connection open and read the data while ensuring data gets stored in text files. If I use method "CONNECT" it does not connect to the stream.
While (True)
webrequest = DirectCast(Net.WebRequest.Create(url), HttpWebRequest)
webrequest.Credentials = New System.Net.NetworkCredential(username, password)
webrequest.Method = "GET"
[code]....
should I increase the buffer size and if so what is the max? that would mean I can read more data at a time and keep up with incoming push. Disparate here.
ACtually also I noticed that it gets stuck on this line
numbytesread = responseStream.Read(bufferread, 0, BUFFER_SIZE)
and then eventually I get disconnected.
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May 17, 2012
I am connecting to a data stream that pushes data continuously and when I tried to set up a network stream I just could not connect and kept getting the 'not found' error. I used the httpwebrequest with webrequest.keepalive = true and started to consume the data by reading into a buffer and then appending to a stringbuilder. Once the stringbuilder reaches max size I flush it to a text file. The problem is that I get disconnected from the data stream because I am not reading the data fast enough. I need to keep the connection open and read the data while ensuring data gets stored in text files.If I use method "CONNECT" it does not connect to the stream.[code]
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Sep 3, 2011
I understand the possibilities for encrypting a connection string in .net v4. I have a win forms application that will be used by multiple people on different machines. I understand that I need to protect the connection string at time of the app being first run on the target machine. However I am concerned that for a period of time my connection string will be unencrypted. I am looking for advice in how to deploy my app with the connection string already encrypted or encrypted during installation. encrypting the connection string in a secure way?
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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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Jan 19, 2011
I'm developing an app in vb.net (visual studio 2008). I have a Teradata back-end that will be supporting multiple users in a production environment. I need to use variables in the connection string as the user/pass will be changed every 3 months.
For the gist of the application:
In it's most basic form - I have a search form which works correctly - it pulls results into a listbox and the user then double clicks the list box which will then open a form that is bound via table adapter to the back-end table (Teradata). My connection string is fine everywhere in the application. My problem is using a modified connection string for the "fill" function of the table adapter once the form is opened.
I'm using the code below for the on-load event and keep getting an "invalid connection string" - again, the connection string works fine everywhere else in the app, and the variables etc... are working correctly.
Private Sub adaptertest_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim DBConnStr As String = "Provider=TDOLEDB;Data Source=TDDEV;Persist Security
[Code].....
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Aug 26, 2009
I'm facing a problem after installation any software setup that has a database in access(mdb file) How to I transfer file path in our connection string.
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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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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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Mar 18, 2012
I am trying to connect DSN from my VB 2008 project. When i try using myoledb.connectionstring="DSN=myDNSname" I get the following error message An OLEDB provider was not specified in the connectionstring.
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Nov 9, 2009
i want to ask what is the difference between oledb connection and odbc connection. I have a case, my office used ncomputing then i have to developed an application using sqlserver 2000 and vb.net 2005, i used oledb connection. When i try to implement it in ncomputing, why user must has admin access level and dbo level in sql server, it seems trouble when all users are admin. But there's a rumor that when using odbc connection, we dont need to give admin access level for users.es.
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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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Aug 18, 2009
I have a program that sends some data on a networkstream through a tcp connection.
[Code]...
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Jan 27, 2012
SQL connection - I planned to create one sql connection object inside my own singleton class (say connectionmanager with Reference counting for 'SQL connection object' which is a member of the class) and open/close the connection whenever needed. As I like to give high importance for performance. And my application is a desktop based application accessing a remote database server (SQL server 2008), and will use only one connection string, 50 concurrent desktop users may access db server. Please advice.
As like many articles say if the answer is "Connection pooling is taken care by ado.net" - Does that mean that scope of connection pool is entire life of Application instance? Or is it in the scope of SQLConnection object?
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Feb 18, 2012
Why doesn't an exception get thrown when this function is called when there is no ConnectionString set for the Connection? I just spent 15 minutes debugging and staring at it and finally figured out it needed the connection string. Shouldn't an exception get thrown?
Friend Function GetValues(ByVal TableName As String, ByVal FieldName As String) As DataTable
Dim cn As New SqlConnection
Dim cmd As New SqlCommand[code].....
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Oct 14, 2010
I am trying to connect sql server 2008 in visual express 2008. at connection() line i am getting error. name connection not declared. anyone can one tell me what may be the reason for that error.
my
#Region "Statments"
Imports System
Imports System.Collections.Generic
[Code]....
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