MySQL Null Exception Error
Jun 7, 2010
I am building a VB.net application using VB Express 2008 which connects to a MySQL database. Right now, I am only selecting records, but will be writing code for update / insert. I have installed the MySQL Net Connector, most recent stable build. I have set a reference to it in project references. It makes a connection and reads just fine, no issues there at all.
My problem is this: When exiting the project (via calling "End") I am receiving a null Exception error. Here is the error[code]....
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Feb 15, 2012
Having problems with null dates in a mysql table. Have eventually found out that I can store a 'null' date in mysql as "0000-00-00" and I can run the 'insert' command to add a record to the mysql table. When I check on mysql workbench I can see the row has been inserted correctly and the date shows as "0000-00-00".However...When I try to load the table into a datagridview, I get an error = mysql Conversion Exception was unhandled = "Unable to convert MySQL date/time value to System.DateTime".
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Oct 20, 2011
I am trying to create a treeview in VB.net, the data has to be loaded from MSAccess 2010 database. When I try to run this program I get error : Argument Null Exception was unhandled, 'column' argument cannot be null and the program crashes. I have pasted the code as under:
Imports System.Data.OleDb
Public Class frmRating
Private Sub frmRating_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles
[code].....
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Dec 10, 2011
It's saying I cant access this object in my class. Why? I'm pretty sure Ive used this method several times before. Below is some bits of code to figure this out. Object reference not set to an instance of an object."
[Code]...
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Dec 14, 2009
Public Class Form1
Dim int As Integer = 0
Dim CustomerTable As New DataTable
Dim instance As New InvalidOperationException()
[code].....
This is the code this exception occurs when i click on the home button of my webbrowser.or i enter any site on the combobox.
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May 20, 2010
I am loading data from an excel sheet using the following code.The first test I did worked fine.But when I tried another sheet it errored on a cell that was blank"Object reference not set to an instance of an object".Even though the sheet in the first test had blank cells.I need the loop to load the blank cell in the datatable
For nRow = 1 To objSheet.UsedRange.Rows.Count - 1
dr = dt.NewRow
For nCol = 0 To objSheet.UsedRange.Columns.Count - 1
[code]...
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May 10, 2009
I have one list that pushes to another list. Think of a shopping cart situation. If you double-click on the white area after the list of items in the first window, I get a null exception error when I push the info to the second window. How can I avoid that error??
Existing Code is below...
Private Sub lstBooksAudio_doubleclick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lstBooksAudio.DoubleClick
If lstBooksAudio.SelectedItem = "" Then
MsgBox("Please Click on an item.")
[Code] .....
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Dec 30, 2009
I'm hoping someone can assist. I'm still learning VB so excuse my lack of knowledge. The below code is a mashup of a code snippet I found that effectively reads from an SQLite database. The initial code snippet consisted of a textbox for input, a textbox for output, and also consisted of a datagrid to store the contents and a button to activate the lookup.
[Code]...
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Jun 24, 2011
In the following code an error arises because the date being passed to the cDate function is Null. However, the catch statement is in error and reports index out of range on the Catch Ex as Exception line. The exception helper says the word Exception is in error and advises that it is index out of range.
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Nov 10, 2009
I am working on a vb windows form application with several connected forms. Its used to manipulate a MySQL database. One of the sub-forms has the following code snippet:
[Code]...
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Jul 8, 2009
i have the following code but when i select button1 i get the following error: Null Reference Exception was unhandled-object reference not set to an instance of an object. - any idea's how to fix it ?i have underlined the line of code that is highlighted when the error occurs
Imports System.Data
Public Class Form1
Dim Ping As Net.NetworkInformation.Ping
[code].....
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Sep 21, 2011
I've moved my Database connection string into my app.config - however its causing a null exception error when i use it
App.Config
vb
<connectionStrings>
[Code].....
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May 29, 2012
Not sure what I am doing wrong, but here is the code.
SQL Server Express 2008 R2
VB 2010
Private Sub FillDataSetAndViewGrid()
[Code].....
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Jul 4, 2010
I am getting a "null reference exception" error when I run my application, this error occurs even before the webbrowser has navigated anywhere. Why would I get this error without a webbrowser document complete occurring?
vb
Dim HTML As String = WebBrowser2.Document.Body.InnerHtml.ToString
If HTML.Contains("Submit Comment") Then EnterData() Else NextURL()
End If
I don't understand why I would get this error when I haven't even navigated anywhere? Forgot to say that this code is inside WebBrowser2 document_complete.
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Apr 13, 2011
I am working on creating an application (game) for a PocketPC with Visual Studio2005 in VB/.NET. I try to dynamically create a (new)button upon clicking a label and assigning certain properties to this button. For this I used below displayed code, but this button does not appear on 'Form1' - which is big enough to display it- but creates an error: A NullReferenceException. Such occurs when you try to reference an object in your code that does not exist, but I think I just did by using'..New..' Who can tell me what is wrong and how to fix this? [Code]
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Apr 28, 2011
Background: I wrote code that will output all the currently logged in User's Active Directory group names. I want the group name (ex: Acomp_user_BIG) via IdentityReference.Translate instead of the current user's SID's (ex: S-1-5-32-544) returned via IdentityReference.Value.
Here is code that I used:
Public ReadOnly Property Groups As IdentityReferenceCollection
Get
Dim irc As IdentityReferenceCollection
[Code].....
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Feb 20, 2012
Due to this error I am getting a default date 1/1/1900. Variable 'dr' and 'dr1' is used before it has been assigned a value. Here's the code:-
[Code]...
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Dec 15, 2011
I have a fairly simple piece of code:
Private _PurchaseDelivery as PurchaseDelivery
Protected Overrides Sub InsertItem(ByVal index As Integer, ByVal item As PurchaseDeliveryItem)
[Code]....
Which is inside a class which overrides a custom list base. The code is occassionaly throwing an unhandled exception, System.NullReferenceException, on this line when used in production:
If _PurchaseDelivery IsNot Nothing AndAlso _PurchaseDelivery.DefaultSKUBinID.HasValue Then
DeafultSKUBinID is declared as an Integer? (Nullable Int) in the PurchaseDelivery class. I cannot see what might be causing this error, why would this be returning an error?
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Aug 12, 2009
When I put a break point to the last if clause in the sub ("If (backOrder < 0) Then", see below) it runs until the break point, if I put the break point further below, I get the following error:
Cannot insert the value NULL into column 'OrderID', table 'WHM.dbo.OrderDetails'; column does not allow nulls. INSERT fails. The statement has been terminated.
I've discovered first hand that it only happens when prodqty is bigger then qtyOnStock, thus executing the if clause.
The code:
Private Sub NCOSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles NCOSubmit.Click
Dim sqlText As String = ""
[Code]....
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Aug 1, 2011
I tried adding a loop inside this loop but continue to get the error "Null reference exception was unhandled" before the loop ends.
For rowIndex = 0 To dgvVisit.RowCount - 2
MessageBox.Show(dgvVisit.Rows(rowIndex).Cells("CoPayCharge").Value.ToString)
For rowIndex1 = 0 To dgvPayment.RowCount - 2
MessageBox.Show(dgvPayment.Rows(rowIndex).Cells("CoPayPaid").Value.ToString)
Next
Next
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Jun 23, 2011
n my project i am to enter a name and a test mark into two separate text boxes and then select the button to store the information into the arrays, one array for names and another for marks, but when it is reset using the Erase <Array> fuction andi try to re enter information, no matter what information is entered i get a "Null Reference Exception Unhandled" Error.I am using Visual Basic 2008.My code is as it says from now:
Public Class frmAdverageTestMarkCalculator
Dim ClosingMsg As String
Dim Closingtitle As String
[code].....
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Jun 4, 2010
I'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.
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Oct 11, 2010
Is there way to insert null into mysql from an empty text field in vb.net
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Jun 27, 2012
visual basic application prompting me a message "Object reference not set to an instance of an object". i have 2 project in one solution. One is developed in c# and other is in vb. i am calling a method of c# project in vb project. the vb code is:[code]when i debug vb project individually it works properly and when i call vb application from c# application, it prompting error. is i missed out any .net framework reference? [code]
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Jul 26, 2011
My site has been running fine for sometime now until recently I see in the event viewer a null reference exception in the DNN core:
DotNetNuke.Common.Globals.GetStatus() in
F:BuildsMaintenanceWorkingDirectoryLibraryCommonGlobals.vb:line
1125 at DotNetNuke.Common.Initialize.InitializeApp(HttpApplication
app) in
[code]....
the line 1125 is:
_Status = UpgradeStatus.None
Which is a property of the Globals class and an Enum Also when this happens it doesnt just do it once then sort its self it does it roughly every minute for an hour or so.I made sure all dataprovider.instances are either in a using or a try catch finally or self closing(if the reader is not used)?
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Mar 7, 2011
I have the following code, which is meant to loop through a list of CheckBoxes and if checked if gets the text contained in the linked textbox through the tag of the Checkbox, i have used it before and it worked fine but this time i am getting the following error:
Null Reference Exception was unhandled
Dim DisCheckBox As CheckBox() = {chk0_6, chk6_12, chk12_18, chk18_24, chk2_3, chk3_4, chk4_5, chkXSB, chkSB, chkMB, chkLB, chkXLB, chkS, chkM, chkL, chkXL, chkXXL, chkXXXL, chkXXXXL, chkW8, chkW10, chkW12, chkW14, chkW16, chkW18, chkW20}
For Each Chk In DisCheckBox
[code]....
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Jul 19, 2009
I keep getting a null reference exception w/this program, and its on the line that declares the array. I've looked it over and over and I just don't see why... Can you let me know if you see anything obvious? I'm also getting an "index out of range" exception, but it looks right to me...I declared everything with an 11 for 12 months, 0 to 11 for the intcount.
[Code]...
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Oct 23, 2009
If Not obj is Nothing and obj.IsActive Then ' null reference exception??constructions like this in C# works, because obj.IsActive is not checked if the first condition is false...
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May 4, 2009
I am using Windows Vista x64 + VSTS 2008. I am debugging the sample program from the following URL (associated sample code for this article),
http://www.codeproject.com/KB/audio-video/CaptureScreenAsVideo.aspx?display=PrintAll&fid=129831&df=90&mpp=25&noise=3&sort=Position&view=Quick&fr=101&select=1160633
But I met with null pointer exception when press the write to file button, here is my screen snapshot.
http://tinypic.com/view.php?pic=14cbfop&s=5
[Code]...
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Apr 4, 2011
i have this sql transaction i am using to make sales.But when ever i run the code it give me this null reference exception.I do not really know what is wrong.
[Code]...
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