Null Check Always Returns Null, If Removed Returns Object Reference Not Set To An Instance Of An Object
Jun 24, 2010
I have some code which gets child items for a menu via the GetChildren function which takes a list of menuData: Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
If menuData.Children IsNot Nothing Then
If I check if menudata.children isnot nothing, it always is nothing because the GetChildren function is yet to run (providing the child items, which do exist). If I remove this check and just have this code:
Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
Then I am presented with a Object reference not set to an instance of an object error on menuData.Children.AddRange(GetChildren(menuData))
I am making use of a 3rd party dll and am encountering some strange behavior in VB, which doesn't occur in C# Perhaps someone can explain what is going on. Anyhow, I am making use of a method in this 3rd party library which accepts an array parameter ByRef. The end result is the variable should remain null after the method call, but it is returning initialized for some reason.
Currently working on the status bar for application. I would like the status bar to display message errors if a user makes an invalid entry. I have a module which contains the main procedure and procedures to change the text property of my status bar. A Call is made to the procedures from one of the forms that requires the user input. The application compliles but I get an unhandled exception of type 'System.Null ReferenceException' Object reference not set to an instance of an object. [Code]
i hav two openfilefialogs(1 and 2). So i also have a listbox. the files opened with the openfiledialogs will be added to the listbox. and when i need to open the files i need to see if they are from which openfiledialog. so
it is like this.
Path.GetDirectoryName(OpenFileDialog1.FileName) & "" & Form3.ListBox1.SelectedItem.ToString 'if this returns a null then go to this Path.GetDirectoryName(OpenFileDialog2.FileName) & "" & Form3.ListBox1.SelectedItem.ToString
I have a WPF application that uses a third-party library to perform a specific task; this library, in one of its methods, executes the statement Assembly.GetEntryAssembly(). If I run the WPF application on debug (by running a .Net exe for testing) the library works properly and Assembly.GetEntryAssembly() returns a reference to the assembly of the executable, but in production I have a different situation that causes me some problems.
I have the following code in my application. When it is executed it brings out a null value at times, where i am sure there should be a value returned. I have checked by running the sql statement in the database and it returns the correct value. What could be wrong with my code? [Code]
Rather interesting bit on this one, I have all the code where it should be working but whenever it hits parse1 it returns the file as null. [code] I probably just need a fresh pair of eyes because I'm not seeing where this is glitching (...or if it's just my computer in this case.)Rather annoying at this point, tried break points and following the execution to catch the error but no such luck.
I just want to check and see if this object is null. if i do not and it is my applications closes.I have also looked into a null reference exception. I will do whatever as long as it handles "null".[code]
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
I have some VB.NET code that creates a TransactionScope instance:
LoggingUtility.LogDebug("UpdateCallTable", "SatComCallDataImporter", "About to associate call data with contracts") Using ts = New TransactionScope() LoggingUtility.LogDebug("UpdateCallTable", "SatComCallDataImporter", "Getting all unimported SatCom calls")
My application is throwing an exception on the call to the creation of a new TransactionScope, with "Object reference not set to an instance of an object.". The exception isn't thrown on my development machine or my test machine; only on the customers production machine, and I have no idea why. I've placed debug lines immediately before and after this line so I'm positive it is this line causing the problem.
A have used TransactionScopes throughout the application and this is the only place throwing the exception on the client machine."About to associate call data with contracts" gets written to the log and the next log entry is the "Object reference not set to an instance of an object".
Code works fine if I move it out of a transaction.I've been struggling with this for 4 days now and have got no closer.
I have a DataGridView connected to a DataSet. I want to allow the user to update and insert new records on the RowLeave and CellLeave events. The Update method works: Me.ExpensesTableAdapter.Update(Me.DataSet1.Expenses)
I am basically trying to access the CLSID portion of the registry... some CLSIDs are working, some arent...
Here is my code: Dim regkey As RegistryKey regkey = Registry.ClassesRoot.OpenSubKey("CLSID" & location & "InprocServer32", False) 'Just Returns null when im looking for a certain CLSID Dim SubKeyvalues() As String = regkey.GetValueNames() Dim subkeyvalue As String subkeyvalue = regkey.GetValue(SubKeyvalues(0))
I'm trying to get data with the methods below and I get null response and can't figure out why. I'm just trying out a different way of using a wcf service from silverlight and I don't understand something that I should.[code]...
The employee object will stay null. If I put a break into the service call and follow through the code it finds the correct record from the database and the return statement shows an object with the correct data but still the employee object in silverlight side will remain null.
By my logic, this should only assign .length to index IF the length of strItem is longer than 0. This check is there in case the listbox is empty, or the user has not selected an item. However, everytime I go through this code without an item selected I get:
I am having trouble with this piece of code. This is an event when a check box is clicked. It gives me an error "Object Reference Not Set To a Instance Of An Object"I am gathering that something here needs to be AS NEW something but I have tried a few things and can not get it straight.
If Me.ckbDefault.Checked = True Then Dim current_indexno As Integer current_indexno = Nothing[code]....
Then, in the aspx.vb code behind, when the user clicks the Save button, I run through a series of Requests to try and add the values that are in these form elements to a SQL string:
Dim DFTestValue1 As String DFTestValue1 = Request("textbox" & c.ToString)
where c is a loop counter to the # of textboxes created (the input value mentioned above that triggers the create) The problem here is that this code works in Internet Explorer but not in Firefox or Chrome. The Request() value returns null and nothing is saved. I hope I've explained this well enough.
I have a vb.net app that I can read a .xls file into a dataset or loop through as oledbdatareader and it gives the same result.Some of the rows have all nulls when I loop through them but if I open the same file in Microsoft Excel I can see that row fine.[code]From the info above the first two SKU values would come through fine but when I get to the 3rd row it would show a null.Is it possible that it kind of inherits the first rows type and since the 3rd row isn't all numeric if nulls it? [code]
I'm using FileHelper to generate object's property. Here is an example of one property:
<FieldOptional(), _ FieldTrim(TrimMode.Both)> _ <FieldNullValue(GetType(String), " ")> _ Public StoreNo As String
As you can see the StoreNo will either have a value or " ", one of the business policy is to check if the StoreNo is empty or nothing if the object's StoreNo is empty or null then the record will not create.
I though about creating an HasValue Function in the class to check the StoreNo and other properties in the object but I feel like it is a hack.
Public Function HasValue() As Boolean Dim _HasValue As Boolean = True If StringHelper.IsNullOrBlank(Me.StoreNo) Then
I don't think this approach is an ideal solution. what if the StoreNo is remove or change to something else. What's the best approach to check object's property?
I have a select statement which was returning the required values but when I changed the OS date from English(US) to English(UK), it now returns null. I believe the problem is concerned with date since in the query am selecting values where the date from the database is the same as the date in a combobox but I don't know what else I can do. It almost looks like the dates in the combox and in the database are not the same and yet the date in the combobox is actually retrieved from the database and has been returning values fine until I changed the system date format.Here's my select command:
cmd4.CommandText = _ "SELECT sum(brought_qtty), recieved_qtty from brought_coffee, centre_weigh where brought_date=#" & _ dtComb.Text.Trim & "#" & _[code].......
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
i am trying to allot a cell value to another cell value basing on some conditions & finally delete one column.my code is as fallows
Dim i, x As Integer i = 0 x = Me.DataGridView1.Rows.Count[code]....
error i am getting is : Object reference not set to an instance of an object.it is extremely surprising for me the same code has worked nice for me but why & how the same line of code is generating this error.
I tryed searching for an user in active directory using the code below but it gives me the error in the title of this post above:
AD = New DirectoryEntry("LDAP://OU=SchoolOUhere,OU=Staff,DC=garrard,DC=ketsds,DC=net", "", "", AuthenticationTypes.Secure) AD2 = New DirectoryEntry("LDAP://OU=_Groups,OU=Staff,DC=garrard,DC=ketsds,DC=net", "", "", AuthenticationTypes.Secure)
Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth. - "Sherlock holmes" "speak softly and carry a big stick" - theodore roosevelt. Fear leads to anger, anger leads to hate, hate leads to[URL]...
The issue is when I try to add a new item to the ArrayList with the following code, it gives me an error:
vb Private Sub btnLabelAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLabelAdd.Click Dim result As String = InputBox("New Filter Label:", "Label List")
Object reference not set to an instance of an object.
I'm not really sure what I'm supposed to be doing with this. It's a new setting I just added and it's empty, so I'm not sure if that has anything to do with it or not. Anyone know what's going on and what needs to be done to get it to accept a value and not want to be "initialized"?
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, "firstname.lastname@example.org", "imap_test") Try
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).
I was create Access database with Access 2003. I create VB project with Visual Studio 2005 Standard With connection wizzard I create coonect with this Access database, select all tablesI see this database inside Data sources and inside Server explorer Test connection is OK When I drag and drop table from Data sources, Wizzard don't create DataGridView, DataSourceBinding etc .. and I see popup window with mesage: Object reference not set to an instance of an object and then "game over"
Protected Sub CompetenciesButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles CompetenciesButton.Click Dim con As String = WebConfigurationManager.ConnectionStrings("foo").ToString()
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
The error occurs on line 19 (For Each customerEntry As DictionaryEntry In Customer) in the second set of code from the default2 class.