Check If An SQL Connection Is Still Valid?
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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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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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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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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Jun 4, 2011
is it possible to check if the customer input his complete name is valid or not?
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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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Oct 10, 2011
I have a txt file with a few settings that get loaded into the Program. These are put into an array. As the array holds different types (int, string, dates etc) its set to object type.
What i am trying to fingure out is how to check the date is a valid format, by returning a false value so i can have a msgbox pupup and say the date in the file is invalid. I cant use isdate() on the string from the file as even if the date format is correct its a string not a date type so i have to convert it first (which is the point it throws an error).
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Jul 22, 2010
I need to check if a character is a valid Key (type) in VB.NET (I need to turn "K" into Keys.K, for example). I am currently doing this to convert it:
Keys.Parse(GetType(Keys), key, False)
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Nov 7, 2010
After I send a post request to login to a site (using httpwebrequest), how do I check if the login is valid?
One way to do it is to read the whole html using
dim reader as new streamreader(response.getresponsestream) dim str as string = reader.readtoend and then check the html for any unique string (e.g. "log out"), to tell if the login is successful.
But reading the entire html is too long, so how do I shorten the process?
I tried
Dim str as string = response.getresponseheader("Set-Cookie")
But str is a blank string.
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Apr 25, 2009
I am trying to create a program that visits a site, and checks urls if they return a 404 page.[code]...
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Feb 2, 2011
I am developing client application I store client details with e-mail address. but I give permission to users to entry valid e-mail address of every client, In that case I will check valid e-mail address for that how to check the given valid e-mail address
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Mar 21, 2012
I'm trying to check if the input in the "enterKey" is 1) Numeric input value, 2) Integer input value, 3) Non-negative input value, and 4) Input value less than or equal to the Maximum Score which is 10. When I enter the number 10, my error message pops up.
Here is my
If e.KeyCode = Keys.Enter Then
If (IsNumeric(txtQuizScores.Text)) _
AndAlso (CInt(txtQuizScores.Text) >= 0) _
AndAlso (CInt(txtQuizScores.Text) <= 10) _
AndAlso (CInt(txtQuizScores.Text) Mod 1 <> 0) Then
[Code] .....
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Nov 22, 2009
Well its not very important, but i have 500 emails (yahoo) and i want to make a program that checks if these emails are valid. Basically i want to send newsletters to these emails, but i want to know if the emails are really valid. How can i do that. I know there are some programs i can use, but i want to make my own program.
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May 27, 2010
Looking for the best way to determine if a URI exists in VB.NET without downloading the actual content. System.IO.FileExists/My.Computer.FileSystem.FileExists can be used locally to determine if a file exists, is there an equivalent for the Web?
Currently I am using a HttpWebRequest to check URI existance using the ResponseStream. This populates the stream if the target does exist and throws an exception if it doesn't. The function is being expanded to also check for PDF files (typically 5MB +), images, etc and it will be a waste of time/bandwidth to actually populate the content into a stream.
In the case of "Success" (the target does exist) I do not wish to download the file or page, simply to end up with a Boolean which indicates the whether something exists at the end of this URI.
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Mar 25, 2010
does somebody knows how to check for a valid IMEI?I have found a function to check on this page: url...But it returns false for valid IMEI's (f.e. 352972024585360).I can validate them online on this page:url...What is the correct way(in VB.Net) to check if a given IMEI is valid? [code]
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Aug 1, 2009
How to deal with a "date bug" that I have encountered in my program. Here is a scenario.
1. My system has a locale of en_US and therefore displays the date as MM/DD/YYYY
2. My program tries to import from a csv file in which it carries out tests on a field to check for a valid date before loading the rest of the data.
3. If the date in the file is in the format DD/MM/YYYY the test fails and therefore the data is not loaded. This is the bug.
I would like code to test for the date string in the csv file that will recognize any date format (locale).
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Apr 23, 2009
I create an empty boolean array check_state(), and then if a condition is met later in the script, I redim it and save a list of check box states as booleans into the array, and later check the array values, but I can't work out how to do this without causing an error if the array was not defined to begin with
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Sep 23, 2011
I cant find any good example of vb.net checking if email is valid, as example "something@yahoo.com"
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Jul 27, 2011
How can I know if I input a valid Birthday of a person in vb2005 windows base. If the user input the current date it must put a message that it is not a valid birthday.
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Jun 18, 2009
See subject of positing for question.
1) I recall seeing a really cool option in VB.NET using LINQ to match using "LIKE%'
2) I know regular expressions will work and I suspect that will result in the shortest code and probably won't be too hard to read for such a simple test.
Here's what I did.
Private Shared Function FileNameIsOk(ByVal fileName As String) As Boolean
For Position As Integer = 0 To fileName.Length - 1
Dim Character As String = fileName.Substring(Position, 1).ToUpper
Dim AsciiCharacter As Integer = Asc(Character)
Select Case True
[Code] .....
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May 12, 2011
Check Email if gmail and valid password length.
Screenshot:
Public Class Form1
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
[Code].....
This code might be useful for validating email address, and for simple email sender/bomber.
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Apr 9, 2012
Is it possible to embed a code or something that can be used to verify an image? In my current project I need to load images and I want to have a code or something that my project can read from the image file before it loads it.Select Image -> Check if embedded code is valid -> Load pic on PictureBox
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Aug 11, 2011
Currently, to avoid errors from being thrown up due to invalid email addresses, I do the following:
Dim mailAddress As MailAddress
Try
mailAddress = New MailAddress("testing@invalid@email.com")
Catch ex As Exception
'Invalid email
End Try
However, rather than depending on Try..Catch, is there a way of validating that the email address will be 100% valid for the MailAddress type?I know there a plenty of regex functions out there for validating emails, but I'm looking for the function which the MailAddress type uses to validate its addresses.
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Apr 26, 2011
Since I sign my project .exe files with my code signing certificate, I want to check in my application MainForm_Load if the executable is signed and the signature is valid?If not signed or signature has been tampered it must exit the code.
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Jul 30, 2010
how 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.
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Aug 19, 2010
how 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.
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Jun 9, 2010
Does anyone have a regurlar expression available which only accepts dates in the format dd/mm/yy but also has strict checking to make sure that the date is valid, including leap year support?
I am coding in vb.net and am struggling to work this one out.
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Nov 18, 2009
I am trying to mkae sure that there has been 16 numeric digits entered into the masked textbox. If not show errror message and if so to call the fucnction ValidateLuhn. When calling Validate Luhn i want the program to tell me if the number entered is valid or invalid using the code in the function:
[Code]...
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Feb 2, 2012
Vb is not my language of choice , but I have to do this for school and I'm not having a very easy time with VB's documentation.I'm just creating a very simple console application that accepts user input: degrees in Celsius, and converts it into Fahrenheit. I want to make sure that if the user just hits enter without entering the degrees in Celsius, then an if else statement will catch and write to enter Celsius again.Here's what I've tried:
[Code]...
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