.net - VB MySql AddWithValue Doesn't Pass The Value Successfully?
Jan 18, 2012
I have the following VB code.Dim cmd As New MySqlCommand("SELECT code FROM decoder WHERE ann_id = @aid", conn) cmd.Parameters.AddWithValue("@aid", 1)Dim reader As MySqlDataReader = cmd.ExecuteReader()
The reader.Read() then gives me nothing, however, if I replace the code by.Dim cmd As New MySqlCommand("SELECT code FROM decoder WHERE ann_id = 1", conn) Dim reader As MySqlDataReader = cmd.ExecuteReader() reader.Read() gives the correct result. Tried using Add instead, doesn't help. What am I missing here?
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Sep 15, 2010
Let's say I have a MySql stored procedure that inserts a record with some nullable CHAR fields. In VB.NET if I don't check for Nothing (or Null in other languages), I get an exception from the db driver, so I write:
command.CommandType = CommandType.StoredProcedure;
command.Parameters.AddWithValue("_name", if(name Is Nothing, "", name)).Direction = ParameterDirection.Input;
And this is the first thing I don't like; I'd like to pass Nothing and the driver knows it has to put NULL in the Db. But then, in the stored procedure, I have to check back the field if it is empty:
INSERT INTO mytable
(name, -- other 200 char fields)
VALUES
(NULLIF(_name, ''),
-- other 200 char fields
)
I have to check for nothingness/emptiness twice. Is there a better, more direct, way? Even worse, for non reference types (i.e: Integers) the check for nothingness makes no sense, since a primitive type can't be nothing (yes, I could set an Integer to a non meaningful value, say -1 for a positive id, but...).
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Jul 8, 2010
I developed a project is vb.net express 2008. Published it and the whole clickonce didn't work. Now I have Visual Studio 2008. I opened my project and have been working on it for weeks now. when I build it today it said biuld successful but the new .exe file etc have not been written to my Release folder.
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Apr 26, 2012
I have a winforms application connected to Mysql using the.Net driver. I written a class to handle to all the database functionality. I use a dataTable to store query results for binding from mysql.
Imports MySql.Data.MySqlClient
Imports System.IO
Public Class MysqlConSjC[code]......
This method does a select query. How would I write a method to insert/update/delete rows of the DataTable in the database?
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Jan 15, 2012
I'm doing an app that adds info to a MySQL BD
Imports MySql.Data.MySqlClient
Public Class curso_add
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
OpenFileDialog1.Filter = "Ficheiros de Imagem |*.jpg;*.bmp;*.png;*.gif"
[code]....
but in the image path doesn't appear the slashes [URL]
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Mar 2, 2009
Note: this is not a duplicate of Jeff's question. That question asked "Is an equivalent?" I know there isn't, and I want to know why! The reason I ask is that I've only just become clear on how important it is, and the conclusion seems very strange to me. The Exception Handling block of Microsoft's Enterprise Library advises us to use this pattern:
[Code]...
The policy is defined in an XML file, so that means that if a customer has an issue, we can modify the policy to assist with tracking down (or perhaps papering over) the problem to give them a fast resolution until we deal with it properly - which may involve arguing with 3rd parties, about whose fault it all is. This is basically an acknowledgement of the simple fact that in real applications the number of exception types and their "recoverability" status is practically impossible to manage without a facility like this.
Meanwhile, the CLR team at MS says this is not an option, and it turns out those guys know what they're talking about! The problem is that right before the catch block runs, any finally blocks nested inside the try block will be executed. So those finally blocks may do any of the following: Harmlessly modify the program state (phew, lucky). Trash something important in the customer's data, because the program state is screwed up to an unknown degree. Disguise or destroy important evidence that we need to diagnose an issue - especially if we're talking about calls into native code. Throw another exception, adding to the general confusion and misery.
Note that the using statement and C++/CLI destructors are built on try/finally, so they're affected too. So clearly the catch/throw pattern for filtering exceptions is no good. What is actually needed is a way to filter exceptions, via a policy, without actually catching them and so triggering the execution of finally blocks, unless we find a policy that tells us the exception is safe to recover from. The CLR team blogged about this recently:
[Code]....
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Oct 20, 2011
Why if you pass an object as byVal into a method is it then treated as if it were byRef? I know you're only passing the reference across when you pass an object variable but why doesn't VB force you to decalre the header as byRef?
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Jun 8, 2011
I am trying to pass some information from a VB form to my MySQL database. i have named all the textbox's the same as the field in the database and checked all my database fields and textbox names which are all correct. When i try to enter information into a form I sometimes get an error at the .executeNonQuery section of the code.
To test, I outputted the SQLStatement string to a textbox ( which pulled through all the fields from the textboxes correctly) then manually inputted the completed SQL query into the database and it worked. But when I try to do this in one go it seems to fail if there is too much text ( if i enter 'a' into each field it works). Are they limits to the size of the SQL query that can be passed from VB?? all the MySql database fields are set to text with no size limits.
[Code]...
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Mar 10, 2011
What is the equivalent of Parameters.AddWithValue in the MySqlClient?
I've tried Parameters.Add and it's not working, but AddWithValue gives me an error.
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Sep 21, 2010
I use codes below to inserts values to database by executing stored procedure.
Dim connstring As String = "dsn=test"
Dim oConn As Odbc.OdbcConnection = New Odbc.OdbcConnection(connstring)
Dim com As New Odbc.OdbcCommand("{? = call sp_test1(?,?,?,?)}", oConn)
[Code]...
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Jul 8, 2011
Is it possible to use "IN" operator together with OleDbCommand.Parameters.AddWithValue ?
I am using Visual Studio 2008 and Microsoft Access 2000.
I have search online but find no solution on it. Below is my code:
Dim conn As New OleDbConnection
Dim cmd As New OleDbCommand
Dim Adapter As New OleDb.OleDbDataAdapter
Dim strSQL As String
Dim dsDoc As New DataSet
[Code]...
Where there is 2 Document No inside parameter @Doc , i can't get any of them. When there is only 1 Document No, then it is ok.Is it possible to use "IN" operator together with OleDbCommand.Parameters.AddWithValue ?
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Feb 8, 2010
ive tried everything:
Me.Close()
Me.Dispose(True)
Application.Exit()
Application.ExitThread()
MyBase.Close()
But the program still executes.
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Jun 8, 2009
A problem developed in a program after some changes were performed. It runs the previously good program. Is it possible to get back the good program's code?
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Jul 15, 2011
I can successfully use the command-line arguments by the code below
[Code]...
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Dec 8, 2011
creating an application using VB 2010 Express. i found data I entered into table were not saved (after I clicked"Save" button)successfully into Microsoft access file which I had added successfully as datasource.These are the codes:
Private
Sub
SaveToolStripButton_Click(ByVal
[code]....
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Feb 8, 2012
I am uploading an excel data to display in a datagridview and when i click on an update button it updates the database.but I want a code that will look up a column and get a value then display in a message box like "Data uploaded successfully for @ChurchID"where @Churchid is a column in the excel sheet but the id is the same but unique for every excel sheet upload If the upload is not successfull then it should give a failed message for that @churchID
Code
Dim i As Integer
For i = 0 To (Me.DataGridView1.RowCount - 1) - 1
Dim Connection As New OleDb.OleDbConnection("Provider=Microsoft.ace.oledb.12.0;data source=C:Documents and Settingsmichael.marteyMy DocumentsVisual Studio 2005ProjectsmyRegistermyRegisterinDebugChurchesRegister.mdb")
[code]....
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Oct 19, 2009
I made an icon for my program and tried to implement it.Funniest thing though, I get a message with the error icon saying the operation completed successfully.But the icon doesn't change, nor is it my icon drop down box when I click the arrow. Ergo, it didn't complete successfully....I am using ASP.NET 2.0 and have read some about this error but I don't see any fixes I can do, aside from what I've tried already.
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Feb 28, 2010
How can i transfer a form successfully from one project to another without messing anything up ?
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Feb 29, 2012
The problem is when I do through through a push button, it works fine, the file is captured, processed and clicking the button calls StartRecord() to start a new recording which enables the timer to look for the silent period but does not rely on the timer to restart the recording after processing - no issues I can do this over and over without a problem.Having it automated through a timer control it fails, after the first recording the timer should restart the recording by calling StartRecord() again but I get an error "The specified device handle is invalid". I thought maybe it was all happening too fast so I tried sleeping in between the restart for up to a full minute with no change, I removed the ProcessSpeech() sub routine from the timer and just had it record, and sleep for a minute then restart and still fail with same error. I can do the manual button start much faster than a minute with no issue.
Private Sub StartRecord()
Dim fileName As String = "c: est.wav"
Dim stream As Stream = Nothing
[code]....
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Feb 6, 2012
Basically Commands has Parameters and parameters has functions like Add, AddWithValue, and etc. In all tutorials i've seen, i usually noticed that they are using Add instead of AddWithValue.
[Code]...
since it saves my coding time. So which is better to use? Which is safe to use? Does it improves performance?
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Nov 11, 2011
I have created setup file and installed successfully. while removing the Application from my system by using Add/Remove programs I got the Error as below,"Error 1001. Exception occured while the installation.System.Io.filenotFoundException.could not load the file of assembly file or one of its dependencies. the system cannot find the file specified."..After that i got one more Error box that says "fatal Error during installation"..By the above errors i could not uninstall the Application from my system.How can i solve this error? and is there any other way to uninstall the application from my Machine?
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Jul 30, 2010
How would I delete only the successful inserted rows for insert and then move the non successful rows up and allow the user to correct the data and get it ready for an insert. If I dont delete the successful rows then I will have multiple inserts of the same dataRow and we dont want that! And if I don't move the data up then it will have blank rows uptop and will end the try and not insert the corrected data. You can better see what logic I am trying to perform at the bottom of my code, right after I insert into the database.
Here is my code.
Private Sub btnLaserGenerateTicket_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLaserGenerateTicket.Click
'Function declarations
'Object declarations
Dim localOutputServer As SQLServer = Nothing
'Variable declarations (Form)
[Code] .....
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Nov 19, 2008
Since it will be run by the user I don't want the user to have to do anything but send the IT department the log file it creates.
What I want to do is see if a folder on the network can be opened successfully. I do not want to ping it, but actually open it and see if it loads. I can do this for a website by retrieving the http status code, but I can't find any references to something similar for explorer.exe. Here is a basic flowchart of this part of the program:
ping server --yes--> access \server_namefolder
--no--> access \server_IPfolder
--no--> Authentication Issue
--yes--> DNS Issue
Note also that just checking authentication won't work because it could also be a DNS problem. I guess I could check them both, but I would rather do it this way if possible (and I don't know how to go about checking either one)
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Aug 9, 2008
im using VS2005. and the built-in sql express.when i run my code in debug mode, i can see that the required number of rows are being affected correctly.but when i actually go and see in the table data, the data has not been inserted/updated.i am using sqlcommand. executeNonQuery() to insert/update data.also, i must add that both executeScalar and executeReader are working perfectly.what could be the possible reason for executeNonQuery although showing the number of rows affected but does not actually do it when seen in the table data?int x = cmd.ExecuteScalar(); // X SHOWS 2 OR 3 depending on the number of rows affected.
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May 17, 2012
i just want to ask about on how to check if i am successfully connected in ms sql 2008 in vb.net silverlight.
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Jul 13, 2011
I'm trying to create an application that sends an email to an smtp-server. The server is not set fixed, but will be looked up according to the domainpart of the email-address where the email should be sent to.
[Code]...
It would be quite useful, to know if the message was accepted by the mailserver and the message was successfully sent. What I am able so far is, that I can get the SMTP-Server error code (if there was an error (StatusCode 5xx) by using the System.Net.Mail.SMTPClient Object and its SendAsync Function. There, if there was an error, I get an Exception-Object in the Callback-Event of the SMTPClient
I'm well aware that not every mailserver will tell me if the mailaccount truly exists and then reject my mail with an errorcode but instead just accept the message and then delete it. Therefore I would be grateful for another Method to check if the mail was sent (note: not read, that would be the read confirmation)
The final purpose would be: Try to send an email to a recipient using it's domains mailserver and if it fails, proceed according to the errorcode (user does not exist -> abort / mailserver did not respond -> use another mailserver if available).
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May 27, 2009
I am trying to successfully multithread a piece of software I have been working on. I have an array of threads 'gen' already working, calling to a method taking a single integer as a parameter (done via typecasting).Now in this thread, when the function gets processed (for each thread a roughly 500 iteration while loop) the index seems to be getting mixed up. As far as I can tell, my threads are messing with eachother and warping values. Now this is happening in locally declared variables inside this function, not global variables.It may be useful to know that I am using a WebRequest via a call to another method. Don't know if that makes a difference or not.
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Nov 14, 2011
I have found this amazing control that does exactly what I need, only problem, its in C#. Does anyone know of a VB version of this code? I've tried using converters, but all of them have failed in successfully converting the project. Maybe one of you guys knows how to convert it?
Anyway, here is the control: [URL]
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Nov 11, 2009
I cannot seem to successfully send the Enter key to a webbrowser control using .net. I can succesfully send postmessage Tab key and it tabs through the links and controls, but it does not click on the link when I send Enter key.The website I am opening has frames, and due to the cross frame scripting policies microsoft forced into the IE control , I cannot retrieve the links from the IFRAMES on the page. So my alternative thinking is to use Tab keys to get to the link and then press Enter.
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Aug 13, 2009
When I try to install controlpad [URL] I receive this error: "Microsoft ActiveX Control Pad Setup was not completed successfully"?
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