Getting An Exception Stating The Null Value Cannot Be Assigned To A Member With Type System?
Sep 14, 2009
Lets say I have two tables:
Parent
PK
ParentID[code]....
These tables have a relationship where the Parent can have 0 to many Children.I wrote this query "Select * from Parent left outer join Children on Parent.ParentID = Children.ParentID", thus returning all Parents regardless of whether they have children.This would return something like this if run directly against the database:
ParentID
FirstName
LastName[code]....
Now what I would like to do is use the ExecuteQuery method on my LINQ data context to run this query and return the set of objects related to it.What I am expecting to happen is have LINQ return two Parent objects one (Joe Smith) with one child in its Children collection and one (Tina Jones) with nothing in the Children collection.However what I am getting is an exception stating "The null value cannot be assigned to a member with type System.Int32 which is a non-nullable value type.I am assuming, since the error message is not very descriptive, that it is talking about the fact the ChildID is an integer and is not nullable and cannot correctly generate a Children object with that value.
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Sep 15, 2010
I have a Job Register Table and that table doesn't have any records.
This is my LINQ code:
Dim QRecordCount = (From LC In CntxtJobDetails.JobRegistrations _
Where LC.JobCode <> 0 _
[code].....
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Aug 18, 2010
When i execute this linq to sql command its given an error "The null value cannot be assigned to a member with type System.Int32 which is a non-nullable value type." 0 Records in my Commotidy Table
I want generate manual number and get the last CommodityCode.My Code as follow,
Dim QRecordCount = From RC In cntxtCommodity.CommodityMasters _
Where RC.CommodityCode <> 0 _
Select RC.CommodityCode[code].....
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Jul 4, 2011
CustomerStreamToRead' is used before it has been assigned a value. A null reference exception could result at runtime.I get that warning once I commented out the streamreader line listed below. The warning shows for the line loading settings(z). The app runs but I don't like warnings in my error list.
Code:
Public Sub LoadSettings()
Dim Z As Integer
Dim CustomerStreamToRead As StreamReader
[code]....
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Jun 12, 2011
Variable 'loNode' is used before it has been assigned a value. A null reference exception could result at runtime.
why I am getting this error?
Imports System.Xml
Module Module1
Sub Main()
Dim doc As New XmlDocument
[code].....
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Aug 7, 2011
When testing the followng code from Mastering VB2010, I get an Unable to cast object of type 'System.String' to type 'System.IFormatProvider' exception.In the Button1_Click event code Dim strmOut As New System.IO.StringWriter(SaveFileDialog1.FileName)the 'SaveFileDialog1. FileName' is underlined with a green squiggle and displays the following tool tip:Runtime errors might occur when converting 'String' to'System. Iformat Provider'.This is apparrently the problem but what does it mean and how do I fix it to get the code to work? 'Code being tested that runs the exception:Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click.[code]
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Feb 9, 2012
Private
Sub cmdExit_Click(ByVal
sender As System.Object,
ByVal e
[code]....
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Sep 2, 2009
I have a large project where we have 2-3 dll projects that are converted from VB6 to VB.NET. We have fixed all the issues that caused compilation errors, and most of obvious issues in running, so now we have basically a program up and running. The exe is created from scratch in VB.NET, using a lot of functionality from the converted dll's (including GUI forms). What I wonder is when I run the program in debug mode, I get a bunch of warnings in the "Immediate Window" saying:
A first chance exception of type 'System.Exception' occurred in Microsoft.VisualBasic.dll
...and some of other type (but most of them in Microsoft.VisualBasic.dll).I was wondering if this is common in projects converted from VB6, or if it is caused by bad design in our code...
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Aug 10, 2010
I'm getting 'Catch' cannot catch type 'Object' because it is not 'System.Exception' or a class that inherits from 'System.Exception'. and 'Expression detected' Code underlined in blue: Catch obj1 As Object When (?)
Private Sub OpenJAMem()
Dim num3 As Integer
Try
[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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Jan 25, 2012
I am trying to get the type of a class by calling Type.GetType(), however it is throwing an null reference exception. I'm supplying the fully qualified name of the class as a string, I'm not sure what I am doing wrong. Here is what I am doing:Type.GetType("The.Name.Space.TheClassName")That is the fully qualified name of the class, it works fine for import statements.
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May 5, 2011
I am using VS 2008, Office 2007, and Win7 Home Premium on my system.I have a simple application which should be a breeze to build. All I am attempting to do is pull data from an Access database with four small tables into a data grid on a windows project. Should be simple, set up the data connection, choose a datagrid from the table in the data source view, drag it onto the page and done, right?I can't get it to work. It will all work fine until I attempt to run or debug the project. The data will not show up. The data grid does, but I get this error: A first chance exception of type 'System.InvalidOperationException' occurred in System.Data.dll
As I said, the project seems to build fine, but it will not pull the data. After the initial build I get the message that Windows will show this page in Compatibility View. Is it something with Win7 Home Premium, or a setting somewhere?
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Dec 22, 2009
I'm using express 2008 build the windows app. and in the app, it calls a webservice which was built by VS2003.It works fine on most PCs. however, there is one PC, it always shows this error:
System.TypeInitializationException: The type initializer for 'System.ServiceModel.ClientBase' 1' threw an exception
....
System.configuration.ConfigurationErrorException: Configuration system failed to initialize ---> System.Configuration.ConfigurationErrorsException:
Unrecognized configuration section system.serviceModel
.....
however, the configuration file was generated by express 2008, and it seems there is no error.
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Apr 13, 2009
I am in a VB.NET class and I am currently modifing a game. I am trying to set up a High Scores system but a Null Refrence Exception error is making me angry.I am trying to reference a class called GameState which contains the Subroutines and variables to use the high scores. Below is the code for a form that is used to show the current high scores in two listboxes.
[Code]...
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Dec 16, 2010
I would like to create a local user on a windows 7 PC, but gets the following error when commitchanges runs. I am administrator on the PC:
A first chance exception of type 'System.UnauthorizedAccessException' occurred in System.DirectoryServices.dll
Here is my code:
CODE:
I am using Visual Basic 2010 ultimate in Visual Studio 2010.
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Mar 21, 2011
get out from the below loop
Shared Function GetIPAddress() As String
Dim sam As System.Net.IPAddress
Dim sam1 As String
[code]....
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Oct 14, 2011
I have a program that creates a Treeview from information procured through an ODBC query and dumped into a dataset. I have three such queries set up via radial buttons as well as a refresh button that triggers whatever radial button is active at the time it's clicked. The purpose of this program is to allow drag-and-drop of selected nodes, ending with a post to the database that officially makes that change of assignment to the new node.
[Code]...
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Feb 19, 2010
When I run my project I get "An unhandled exception of type 'System.StackOverflowException' occurred in System.Windows.Forms.dll"
Public Class frmViewReport
Dim objForm As New frmViewReport
Private Sub frmViewReport_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
objForm.ViewReport("C:a2.rtp", , "@parameter1=test�mter2=10")
[code]....
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Nov 16, 2009
I have the following code running, the first time I change the selected index, everything runs smoothly. However, if I try to change the selected index again, nothing happens and the subcategories combobox values do not change.
Private Sub cboMainCategory_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cboMainCategory.SelectedIndexChanged
'* make sure the combobox is fully loaded
[code]....
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May 6, 2009
I keep getting an eroor this error says: An unhandled exception of type 'System.ArgumentOutOfRangeException' occurred in system.windows.forms.dll Additional information: Specified argument was out of the range of valid values.
Option Strict On
Public Class frmWeeklyReport
Inherits System.Windows.Forms.Form
[code].....
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Feb 12, 2011
A first chance exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll It displays in my Immediate Window when i run my program, I'm using a text reader to read a number of XML files using background worker...most the time it stops so something is wrong but sometimes it works fine.
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Jun 2, 2011
how do I overcome it? I have created a class and compiled into .dll This code
[Code]...
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Feb 6, 2010
I am working on a card game, and i get this werid error:
A first chance exception of type 'System.Reflection.TargetParameterCountException' occurred in System.Windows.Forms.dll
The code that is cousing this error is:
Private Delegate Sub ShowcardDelegate(ByVal test As String, ByVal objtest As Object, ByVal value As Boolean)
Private Sub Showcard(ByVal test As String, ByVal objtest As Object, ByVal value As Boolean)
If objtest.InvokeRequired Then
[code].....
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Jun 11, 2009
what does "A first chance exception of type 'System.InvalidOperationException' occurred in System.dll" means? it occur after the bold sentence of my program.
Dim count As Integer = 0
Dim missing As String = "Missing Ingredient:"
For Each strStore In strDownload
If Not strDownload Is Nothing Then
[code]....
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May 3, 2011
Brief of my project: Taking attendance using RFID reader and RFID passive tag. Main tasks:
1) Scan a Tag and Tag ID is transmitted to GUI.
2) Tag ID is matched with Student ID in database.
3) Successfully matched Student ID is displayed on GUI and LCD.
When i had experienced this problem, student ID was only display on UI but not LCD. After that, my system hang. This happened only when the data of tag scanned is taken from text file through OpenFileDialog. Manually add of data via UI just work fine.
[Code]...
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Sep 7, 2009
i am receiving the following error message when I debug my application, and I do now know what the problem is. This code has worked before but I don't know why.A first chance exception of type 'System.Net.WebException' occurred in System.dll
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Dec 28, 2009
I have a project that I am working on and I just recently transfered it from an XP machine to a Windows 7 machine. Both machines are running VB Studio and the only thing that changed was I moved it from the XP machine to the WIndows 7 environment. I have not changed any of the code, I just transfered it and ran it to make certain nothing happened.
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Aug 13, 2009
In Visual Studio 2008, if I do this:
[Code]....
Does anyone here know how to get the above to work WITHOUT warnings being generated?
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May 31, 2010
In the following code i get a warning at line 59:Warning 1: Access of shared member, constant member, enum member or nested type through an instance; qualifying expression will not be evaluated.and.. At line 78 I get this Warning:
Warning 2 Property 'SelectedCustomer' doesn't return a value on all code paths. A null reference exception could occur at run time when the result is used.
The program compiles and runs well, but i cant' undesrtand the reason for these warnings. Any Idea ?
1: Public Class Form1
2:
3: 'Form level members
4: Private objCustomers As New ArrayList
[code]....
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Aug 3, 2009
Event type clr20r3 p3 4a5c12c0 system.net.sockets.socket Exception and Application crash on some system. while running well on others. i go thorugh many forms and search a lot on google but not able to resolve the issue.
[Code]...
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