Null Reference Exception Was Unhandled By User Code?
Feb 19, 2010
i develop the following code in vs2005, now i just using this module in my new project @ vs 2008..But this error was araised. I cant able to fix this problem...
Private Sub DataAccess()
Dim errHandle As New ErrorHandler
Dim lobjCommon As New eCopsCommonFunctions
[code].....
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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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Jun 9, 2011
started learning vb.net..encountered this problem in this code: Private Sub NavigateRecords()
TextBox1.Text = ds.Tables("stdDataSet").Rows(inc).Item(0)-error msg appeared here sayin null reference evception was unhandled. Object reference not set to an instance of an object.
TextBox2.Text = ds.Tables("stdDataSet").Rows(inc).Item(1)
TextBox3.Text = ds.Tables("stdDataSet").Rows(inc).Item(2)
TextBox4.Text = ds.Tables("stdDataSet").Rows(inc).Item(3)
[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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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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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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Jan 22, 2012
I'm using vb.net and sql server 2000 for developing my application....The problem i'm having is the Null Reference Exception on the Following line of code:
Dim cmd5 As New SqlCommand("select crtns_removed, pieces_removed, scheme from Outgoing_Invoice where invoice_no = '" & Me.ComboBox5.SelectedItem.ToString.Trim & "' And category = '" & Me.ComboBox1.SelectedItem.ToString.Trim & "' and item_name = '" &
[code].....
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Feb 5, 2012
I have a really simple user control.Using the Designer I put two TextBoxes on it, nothing else.Here's the entire .vb file for this user control:[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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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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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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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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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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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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Sep 13, 2010
Now, when I try to debug my program, it immediately throws the exception below, this is before entering the program itself if I understand correctly. Any advice on how to resolve this? Between now and the last time I tried running debug, I had tried making a section of the program MDI, but gave up on that and delete that code. Also none of that part of the program is even in a position to be ran (the initial interface and onward do not execute that code)
[Code]...
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Feb 21, 2012
I'm currently taking a VB class and i'm having trouble running my program properly.[code]
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Feb 10, 2010
write know i am gettin null reference exception due to followin code
Imports System.Xml
Imports System.IO
[code].....
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Jul 13, 2010
in the ReadFile() Sub, if the user tries to read a file that is not there he gets an exception
which results in the 2nd line in the Catch being executed. So far so good. But the 2nd line of
code in the mnuOpen_Click then gets a System.NullReferenceException which I don't understand since
the mnuOpen_Click code all works fine when called from the Open menu item. The exception
information suggests I use the "new" keyword to create an object instance, but in all my reading
and all the different ways I've applied the keyword New to the code, I've not been able to figure
out how to do this.[code...]
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Feb 4, 2011
i keep getting this null reference exception error and i can't figure out what i need to do to fix it. I have this in the form
[Code]...
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Mar 18, 2012
keep getting this null reference exception error and i can't figure out what i need to do to fix it.I have this in the form
Private Sub cbLookUp_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cbLookUp.Click
Dim webDownload As New Net.WebClient
[code].....
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Aug 5, 2011
I get a warning message that reads " Variable 'cust' is used before it has been assigned a value. A null reference exception could result at run time.", but it occurs in my vb file "Northwind.vb with the following code:
Public Class Northwind
Private cust As BizObjects1.Customer
Private Sub frmCustomer_Load( _
ByVal sender As System.Object, _
ByVal e As System.EventArgs) _
Handles MyBase.Load
[Code] .....
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Oct 18, 2011
I'm trying to catch an invalid entry in a textbox that I use to enter numbers using the subroutine below.
In the Catch blok I want to change the ForeColor of the textbox that contains the invalid entry.
This did function but now gives me a null reference exception on the line where I change the ForeColor.
Private Sub SaveParm()
Dim Temps(2, 2) As Double
Dim Cname As String = "Text0"
[Code]......
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Jul 2, 2009
does any one know the reason of why I get Warning in the Finally block in vb.
[Code]...
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Mar 28, 2011
Been looking at a lot of post/articles about using Iif(). All of this started when I tried to use IIf() like a conditional operator much in the likes of C/C#/C++ etc.What I tried to do exactly was exactly in the lines of this of the following post:Using VB.NET IIF I get NullReferenceException
However, the solution I had implemented was borrowed from the following msdn site:
[Code]...
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May 3, 2012
I've got a little problem. I'm trying to choose a background for the program based on Settings, but I'm getting a Null Reference Exception and I don't know what I'm doing wrong. Here's the
[Code]...
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Sep 25, 2009
I'm having some trouble with breakpoints. I'm trying to debug a null reference exception. However if I set a breakpoint right before the null exception normally occurs, the null exception stops occuring. Here is a (very) simplified code snippet to give an example of my code.
[Code]....
In my real project, the line that calls DoSomething will throw a null reference trying to access MyChild. However if I put a breakpoint at that line, MyChild exists, and the call goes through without a problem. In the past, this was usually sign of a race condition in my code. In this scenario however, there are no other threads that modify MyList or any MyParent objects. What could possibly occur when visual studio breaks into code that preserves MyChild object that does not occur when no breakpoint exist? In my real project, the line that calls DoSomething will throw a null reference trying to access MyChild. However if I put a breakpoint at that line, MyChild exists, and the call goes through without a problem.
In the past, this was usually sign of a race condition in my code. In this scenario however, there are no other threads that modify MyList or any MyParent objects. What could possibly occur when visual studio breaks into code that preserves MyChild object that does not occur when no breakpoint exist?
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Nov 16, 2011
I have a simple query as below:
Dim sizings = From a In db.Sizings
Where a.Customer.ID = customer.ID
Select a
If sizings.Any Then
.....
The sizings.Any line is throwing a null reference exception. I thought I was meant to use .Any to determine if there were any rows returned?isnothing(sizings) returns false.
Edit - Resolution:Don't use null objects in the LINQ Query!
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