NullReferenceException Error In VB Application?
Apr 11, 2011
I'm building a voting system for calls, and have tried to build it in VB. So far this is what I have:
Dim con As New OleDb.OleDbConnection
Dim dbProvider As String
Dim dbSource As String
[code]....
This code is contained within a "Record Call" button. On the form, there are four radio buttons, all with different text values which should be entered in to the "voting" table.My problem is that when I select a radio button and click on "Record Button" it then displays this error:
NullReferenceException: Object reference not set to an instance of an object.
This error is displayed on the line
dsNewRow = ds.Tables("voting").NewRow()
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Nov 21, 2009
Okay after searching two listbox's on a form I am trying to put a number as a string in a label setup for that but keep exgetting a NullReferenceexception error on the label. Label being "shippingDataLabel.text".e is my code;
Public Class MainForm
Dim fifteenShipping As Integer = 15
Dim twentyShipping As Integer = 20
[code].....
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Jun 3, 2009
I have made a tic tac toe board and when i go to debug the application i get a "NullReferenceException was unhandled".
this happens diring this part of the code:
Dim x As Integer = Val(index.Chars(0))
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Jun 3, 2009
I am getting a NullReferenceException was unhandled error when i run my debugging in this part of my code: Dim x As Integer = Val(index.Chars(0))
what can i do so this will stop and my program will work?
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Sep 18, 2011
Doing some homework on unit testing and in all honestly i just don't get why i get this error.
i got a simple method that select all text when tab and testing if the actually textbox1 is selected. I just don't get why i'm getting a nullReferenceException at target.txtbox1_Enter(sender, e)
Private Sub txtbox1_Enter(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtbox1.enter
Dim txtBox As TextBox
[Code].....
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Jan 3, 2011
I have the follwing codewhich transfer the value from NumericUpDown64 to the array Conc(0,0) which is part of the structure USerInput:
UserInput.Conc(0, 0) = NumericUpDown64.Value
When I run the program I recieve the NullReferenceException was unhandled. Object reference not set to an instance of an object.
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Apr 8, 2009
Im getting an Error saying:"NullReferenceException was Unhandled - Object reference not set to an instance of an object."I have no idea what this means as a beginner,
Me.FilmTableTableAdapter.Fill(Me.DVDDatabaseDataSet.FilmTable)
Dim con As OleDb.OleDbConnection = New OleDb.OleDbConnection("Provider=Microsoft.jet.oledb.4.0;data source=|DataDirectory|\DVDDatabase.mdb")
Dim cmd As OleDb.OleDbCommand = New OleDb.OleDbCommand("SELECT * FROM FilmTable", con)
con.Open()
[Code]...
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May 5, 2009
We sporadically get errors when we try to update a tool tip, like this:
ToolTip.SetToolTip(myLabel, customDataStructure)
The error we get is a NullReferenceException: Object reference not set to an instance of an object
Does anyone know the cause of this? Is a simple Try/Catch that eats the NullReferenceException a feasible option? We don't want our entire application to blow up when we get this.
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Mar 25, 2011
Private Sub btnSendMsg_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSendMsg.Click
Dim con As New OleDb.OleDbConnection
[code].....
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May 11, 2009
I am slowly getting used to working with classes and for the most part am getting things to work. This problem has me stumped though. Below is an abbreviated version of the code. The form class is:
HTML
Public Class Form1
Private Lines As New List(Of DblLine)
[code].....
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May 27, 2012
I basically made a listbox, a button, and a popup window. The button openes the popup window, in that window you type some text, press "OK" and the text gets added to a list box. Simple right? Guess not...-Textbox1 is the textbox in wich you input text.-Label1 is the label on the popup window that tells you what to do. It's text is either "Edit name:" or "Input name:"This is the function if you click "OK".
If Label1.Text = "Edit name:" And Textbox1.TextLenght > 0 Then
Form1.name_list.Items.Remove(Form1.name_list.SelectedItem)
Form1.name_list.Items.Add(ime_osebe.Text)
Else
[code].....
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Jan 21, 2011
Debugging Error "NullReferenceException Was Unhandled'. I have the following code on my form
[code]...
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May 11, 2011
Error occuring at line: SqlDataSource3.UpdateParameters("TechID").DefaultValue() = CInt(technicianRow("TechID"))
Here is full VB code:
[code]....
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Jun 20, 2012
I'm trying to add objects from a class I created using data from an excel worksheet to a list using a for loop [code]When I run it I receive "System.NullReferenceException was unhandled by user code Message=Object reference not set to an instance of an object."
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Jan 28, 2009
I have a somewhat weird problem with a program i'am writing in VB2005. When I debug the program and start 1 backgroundworker (got 8 different backgroundworkers in the program) in VB2005 nothing goes wrong, but when i'm starting 2 or more backgroundworkers I get an NullReferenceException when trying to read from a MySQL database (withing a few minutes in debugging). This error isn't always in the same backgroundworker, but is always in the same block of code in a backgroundworker (1 of 8). I tried different approaches in getting the results I need, for example with read1.HasRows(), but this also didn't workt... the MySQL table doesn't also seem to be the problem.
Line 8 is where I get the error (read1.Read())... This is a snippet from backgroundworker1, but is also randomly happens in the other 8 backgroundworkers as well... When I'am trying to read te content of read1 is says "Nothing" when the error occures...
[Code]...
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Mar 26, 2011
[code] this is my code n i want to store data at runtime in the my database.i used data base as an access07 and my platform is vb.net..Now come to the point when i run the project it terminates when i'm inserting my data in the access file.[code]
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May 22, 2012
I have been trying to figure out the source of error in my application. What this function (GetConcentrations()) is to display data from my database onto a DataGridView. The function is called in the PageLoad but works fine but when I call it in another Sub, I get this error.
Here is the code:
Private Sub GetConcentrations()
Dim conString As String = ConfigurationManager.ConnectionStrings("dbAsthmaConnectionString").ConnectionString
Me.dataAdapter = New SqlDataAdapter("Select * from tblConcentrations", conString)
[code]....
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Jan 19, 2009
My code
Dim pointer As Integer, index As Integer
For pointer = 1 To 6
For index = 0 To 5999
[CODE]...
All i get is an error message saying NullReferenceException was unhandled the bold part is were it says the error is
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Aug 14, 2009
I'm trying to run a simple database and im getting a "System.NullReferenceException" error ) & "Additional Information:Object reference not set to an instance of a object" .
txtItemName.Text = rowCurrent.Item("ItemName") <-- highlighted in yellow
Code is as follows:
vb.net
Imports System.Data.OleDB
----------------------------------------------------
Public Class Form1
[code]....
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Aug 3, 2011
getting connected using an app.config instead of hardcoding since yesterday evening and I either can't find any more info on the net that helps or I'm too new to understand it all. The exception is occurring on the line assigning the connectionstring to 'returnvalue'.
Imports System.Configuration
Imports System.Data.SqlClient
Public Class Form1
[code]...
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Dec 7, 2011
So, concering my project: I am trying to control an RC Car via Kinect, until now I got it working with key control only (eg WASD). So, I am using a Velleman K8055 Interface Board + the Kinect and VB Windows Forms. So far, so good, I created 4 Forms: menu, info, kinect-controls + wasdcontrols window. The error only occurs for my kinect-controls window (german name: Steuerung.vb) & that's my source
[Code]...
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Feb 7, 2011
I have created a very basic web service in vb.net using vs 2008. When I run the service within visual studio debugger, the service runs fine and gives me the expected results. When I deploy the service to the server and invoke it from a client, it always throws a NullReferenceException error when trying to access the data. More specifically when I call the DbConnection open() method within a dbhelper executeScalar method.
I'm using a custom dbhelper class I found on the web here: [URL] The only thing I've changed is the _factory at the top points to Providers.Odbc (since I'm using a ODBC connection). Like I said previously, the service (and the dbhelper class) work as expected within VS- it's only once I deploy it that it seems to bomb out. I've even tried hard coding the connection string in case it was having problems getting that but no difference there.
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Jan 18, 2010
For i = 1 To 60
Me.Controls("picturebox" & i).BackColor = Color.White
Next
i want to change backcolor of picturebox but when i run program,i get this error :
An exception of type 'System.NullReferenceException' occurred in EZEE Restaurant.exe but was not handled in user code
Additional information: Object reference not set to an instance of an object.i go to Project->Add reference and then look for "System.NullReferenceException" but i don't find it.
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Oct 19, 2009
The code below is used to check if the application setting, an arraylist is populated or not via the count method.
When running the program fails with error "NullReferenceException was unhandled" as initially the setting (arraylist) will contain no values.In similar circumstances I would declare a new instance of the object or set value to string.empty or check if DBNull.
I know application settings have a save method but to reference/load them one is not needed.I also left the value field in the projects -> settings to be empty.[code]...
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Nov 29, 2011
Here are parts of my
Dim setting As My.MySettings
lvl As Integer
Dim xp As Integer
Dim xpt As Integer
[code]....
I have done the settings as type integer and set the values that I wanted but I get this error: A first chance exception of type 'System.NullReferenceException' occurred in Click Game concepts.exe
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Jan 12, 2010
i am using VB.net 2003 and i am trying to get the number of rows of a dataset from form1 into form2 in order to use it for something else and i am getting the error"System.NullReferenceException occured...Additional information: object reference not set to an instance of an object"...my code is like this:in form1:Public x as integer= me.dataset.table.rows.count here it gives me the error
in form2:
dim frm as new form1
msgbox(frm.x)
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Oct 23, 2009
I have recently gotten my hands on a free, open-source IMAP connection API.So far, I have been successful in creating a connection to one of my accounts.Where I'm getting stuck is retrieving folders and/or emails from those folders.Does there happen to be anyone here that is familiar with this API, or even Gmail (particularly the folder structure for IMAP)?
If not, here is a link to the DLL that is listed on sourceforge and the company's website that created it (if you feel like testing):
Koolwired
Sourceforge - Koolwired API
I have created a test account so feel free to use the code below without worrying about username/password issues; I'll just delete it when I'm done with it.Here is the code I have made so far for making a connection:
Dim gSession As New Koolwired.Imap.ImapConnect("imap.gmail.com", 993, True)
Dim gAuthenticate As New Koolwired.Imap.ImapAuthenticate(gSession, "imap_test@serysoft.com", "imap_test")
Try
[code]....
When I run that code, I get an error that states:System.NullReferenceException: Object reference not sent to an instance of an object. (The bold line in the above code).
Now, I'm not sure exactly what that means. Does that mean it tried to access the server and "INBOX" doesn't exist so it gets returned a NULL value? Or is it possibly the coding itself?Maybe the Gmail folder system is weird due to the fact they use labels (even though from what I have read online, the labels act as the folders in the IMAP system).
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Jan 27, 2011
I'm getting System.NullReferenceException error when I try to add the employee info to the Employees list.
[Code]...
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Apr 18, 2010
I got the following code from the demo code samples and just changed the textbox names. But it throws an error:
Private Sub Fill_TextBox()
Dim Num As Integer
Dim DSet As DataSet
[code]....
The error is:
System.NullReferenceException:Object reference not set to an instance of an object.
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Oct 30, 2011
I am completely new to ASP.NET and VB as well as C#. I am trying to add customers to a contact list out of a DB. Then the list can be referenced to call them up. But when I try to run it I get System.NullReferenceException: Object reference not set to an instance of an object. In line 19.
Here is my code:Page 1 is default page...it connects to the database and grabs the contact information and allows me to select the current contact and add them to a listbox on a separate page:
Imports System.Data
Partial Class _Default
Inherits System.Web.UI.Page
[code]....
The error occurs on line 19 (For Each customerEntry As DictionaryEntry In Customer) in the second set of code from the default2 class.
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