Adding Row To Database And Get NullReferenceException Was Unhandled?
Sep 6, 2009
Using Visual Basic 2008 Express Edition, and trying to set up code for an Add button to add a row to an SQL database. The code below is copied from the Help, and modified to reflect the fact my dataset is called Test_SQL_DbDataSet, my table is called Details, and just 2 columns at the moment .. "ID" and "Detail"
Dim newDetailsRow As DataRow = Test_SQL_DbDataSet.Tables("Details").NewRow()
newDetailsRow("ID") = "10"
newDetailsRow("Detail") = "Maint"
Test_SQL_DbDataSet.Tables("Details").Rows.Add(newDetailsRow)
When I select it, I get a "NullReferenceException was unhandled" error saying "Object reference not set to an instance of an object"
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Sep 19, 2011
This never happened to me, and the less data one has (usually) the less you can say what happened.I am trying to write a simple query analyser. I randomly receive these kind of crashes:
[Code]...
The file specified above does not exist. The place where it crashes is wrapped with Try-End Try. Moreover, yes, I have the painting event set up but it should not concern it (or maybe it does?). I have to add that I use visual basic express edition. The error occurs ocasionally - sometimes when I'm lucky nothing happens, and when I'm not then I get this crash.
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Jan 25, 2012
vb
Imports System.Windows.Forms.HtmlDocument
Public Class test_vbdotnet
Private Sub runtime()
[Code].....
I want VB.NET to get access to the innerText and make a if statement out of it. But it always returns error. (see the comments for details.)
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Nov 30, 2010
This is driving me slighty madder than i usually am. The thing thats bugging me is the EXACT same code works in a test project i did with an sdf database.See my comments in the code
vb Private Sub tbScan_KeyUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles tbScan.KeyUp
[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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Dec 10, 2010
on Form1, i have a combobox1 where i have 15 values. im using a case statement with those 15 values to decide what is the next form to go to. i need to make sure the user cannot add in his own text to it or click the NEXT button without having any value at all. how do i add these "exceptions" to my code?
i would think any exception would go before the case so that it could tell you didnt put in the right answer before it looks through the case statment and give you a nullexceptionhandler reference.
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Aug 20, 2010
I am working on my project with the listbox, I am reading the strings through the text file and split the strings to input them on the listbox.[code]When I selected the item on the listbox, I get the error.Error: Object variable or With block variable not set.
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Nov 9, 2011
I can't work out what's causing it. The error report says "Object variable or With block variable not set." for the line "allSlotLabels(i).Image = imgCherries". This line is no different from the other, so I guess it's just the error it picked up first after randomly generating the number.
[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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Jun 22, 2011
System.NullReferenceException was unhandled
Message=Object reference not set to an instance of an object.
Source=Image Invoice Management
[Code]......
i do understand that the list count is 0 so shouldn't it be declairing Start_Pos = 0
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Mar 15, 2012
I got two forms.
Form 1 I ask the user a number of guest
Form 2 I ask each guest their name, their age
I decide to make a loop throught form2 array base on the number of guest but then I got this error. NullReferenceException was unhandled.
Private Sub btnBook_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBook.Click
iTest = CInt(txtChildren.Text)
Do Until (iCounter = iTest) And (bIsNextClicked = True)
PassengersDetails(iCounter).ShowDialog()
Loop
End Sub
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Feb 22, 2008
I am new to vb.net 2005 and am desperate in need of solution as I faced error on the following codes.
Public Class Form1
Private PreviousTab As TabControl
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Me.Load
[Code].....
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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 15, 2011
I'm try to use NATUPNPLib to use UPnP to do and automatic port forward in my router but I keep getting and error that I'm not sure how to handle.Here's the part of the code with the error.
Imports NATUPNPLib
Imports UPNPLib
Public Class Form1
[code].....
I've tried making sure Windows 7 has Network Discovery on and that UPnP in enabled in my router, could it just be my router and how it handles UPnP?
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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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Jan 23, 2012
i have a code that grabs an image from a site, this works fine and it does get the image fine, but every now and again my internet runs slow and it takes a while for the image to pop up thus causing the error:[code]How would i make it display the msgbox if it returns NullReferenceException error ?
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Sep 27, 2011
i have a small problem with my code that only happens every now and again.Im using multi threading on this and every now and again i get this error: System.NullReferenceException was unhandled Message="Object reference not set to an instance of an object."
Some times the program completes perfect with no errors and sometimes i get the above error.When i get the error there is always 1 item left in the list but when it completes perfect no items are left.Again this error does not appear every time, only every now and again. For example i had to run my program like 20 time to get this error, 19 times it worked perfect with no errors and 1 time with this error.
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Feb 15, 2012
i have this code in my btnsave..it can detect conflicts but after that a dialog box saying: An unhandled exception of type 'System.NullReferenceException' occurred in AppointmentSchedulingClient.exe
Additional information: Object reference not set to an instance of an object. and it points to the green one below.
If Val(cbostart.Text) > Val(cboend.Text) Or Val(cbostart.Text) = Val(cboend.Text) Then
MsgBox("Error in time.", MsgBoxStyle.Information, "MESSAGE")
[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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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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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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Jul 19, 2010
I am trying to transfer data from a VB form to an existing Excel 2003 file. This is the code I am using, but it is throwing up the following error:I have coded in VBA but am new to VB.NET and am struggling with setting up the objects
Dim oXL As Excel.Application
Dim oWB As Excel.Workbook
Dim oSheet As Excel.Worksheet
[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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Apr 1, 2011
I'm getting a 'NullReferenceException was unhandled' exception when a NumericUpDown control is cycled too quickly. To slow it down I've disabled the (NUD) control and set a 200 Interval Timer to re-enable it, but the exception is still happening.I don't want the slow the control down any further, I'd rather try to handle the exception, but can't find any help on how to do that.This is essentially the code which is incurring the exception, at the (4th) line... Dim p... : -
For b = 0 To 8
z = Pic(b)
[code]....
I figure I need to ensure each image is happily installed in it's 'Box before I try to load the next one, or it may be that I just need to check that the last one is 'in' before I call the next bit of code (which calls this bit again if I'm too fast) It all works perfectly well if I don't go too fast.
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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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Apr 15, 2009
I'm finishing up working on the high score list of my Jeopardy game. The only problem that I'm running into is when I try to start from scratch without a textfile in the Debug folder.I get a NullReferenceException was unhandled - Object reference not set to an instance of an object. I get this message with the line If (myPlayers.Length - 1) > 2 Then just before I start to compare the scores and reorder the list by score if necessary.I already declared myPlayers as an array of structures in the beginning of the form.
Private myPlayers() As Players
It writes the name and score to the file, but then gives me that error. My goal is to only fill the file with the three players names and their scores.I figured since the file doesn't exist, I'm doing something in that specific code that effects my reference to myPlayers but I can't figure out what exactly. I tried adding
If (myPlayers.Length - 1) > 2 AND File.Exists("highScore.txt") Then
but its still giving me the error.
'read in scores, add scores to file or create new file if neccessary
If File.Exists("highScore.txt") Then
Dim InputFile As StreamReader
[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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