.net - Constructor-chaining And Null Reference Tests?
Jun 3, 2011How to test the null value BEFORE calling the other constructor?
' class MyHoyr '
Public Sub New(ByVal myHour As MyHour)
' Can't doing it here !!!! '
[code]....
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.net - Setting SqlDateTime.Null In A Constructor?
Mar 6, 2009How do I set a null value for an optional DateTime parameter in a constructor?
I'm using the following constructor below and I want the optional parameter admissionDate to be a null DateTime. Setting it to Nothing actually gives it a value (something like #12:00:00 #).
Public Sub New(ByVal obj1 as Object, Optional ByVal admissionDate As DateTime = System.Data.SqlTypes.SqlDateTime.Null)
Null Reference Exception In Line Checking For Null?
Dec 15, 2011I 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?
Changing Object Reference In Constructor Parameter?
Oct 30, 2011I'm trying to change the reference of a variable passed from one form to another in the constructor of the recieveing form but after I've changed it the original reference still remains in the source form. Why is this and can I force it to accept the new reference?
View 12 RepliesVS 2010 Pass By Reference To Constructor Of A Class?
Feb 11, 2012Implementing a simple MVC in vb. The controller instance creates and holds instances of the model and view:
Public Class Controller
Public Property myModel As Model
Public Property myView As View
[code].....
Error: Reference To A Non-shared Member | Constructor; Pass Variable
Mar 13, 2010I've been trying implement Constructor method in passing variable between two forms.Just a rough user interface guide - issue Invoice. User would type in all the Customer Name, Document Number. Once he reached Item Details, a Child Form would pop-up for the User to select/search the Invoice's Item; Once selected, the selected item would showed in the primary Form.
What I had tried is, the Constructor method worked perfectly when it is self-contain in a new project, yet to be implement in my application.But when I implemented, there is an error: Reference to a non-shared member requires an object reference.
[Code]...
.net - Null Reference But It's Not?
Jun 2, 2010This is related to my previous question but it is a different problem.I have two classes: Server and Database.
[Code]...
The problem is in the LoadTables in the Server class. When it hits Databases.Add(db) it gives me a NullReference error (Object reference not set). I don't understand how it is getting that, all the objects are set.
Null Check Always Returns Null, If Removed Returns Object Reference Not Set To An Instance Of An Object
Jun 24, 2010I 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
menuData.Children.AddRange(GetChildren(menuData))
End If
Next
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
menuData.Children.AddRange(GetChildren(menuData))
Next
Then I am presented with a Object reference not set to an instance of an object error on menuData.Children.AddRange(GetChildren(menuData))
How To Avoid A Null Reference
Jan 8, 2011I have been trying to use sockets in VB.NET and once I cannot understand how to avoid a null reference. [code] I have tried introducing sock as 'New Socket', but this gives me 'Overload resolution failed because no accessible New can accept this number of arguments'.I also cannot simply add '= Nothing' onto the end of my declaration since this still gives a null reference.
View 6 RepliesNull Reference Exceptions
Jan 29, 2011I'm practicing on this one, and I know it would be better to just use a string variable instead of a class. I have another working program using a string variable, but on this one I wanted to make it use an array of class objects.
I keep getting null reference exceptions at the line where the object is assigned the textbox text.[code...]
Null Reference From KeyDown?
Dec 16, 2010How do I check for a null object in a subroutine handle?
Private Sub Form1_KeyDown( _
ByVal sender As Object, _
ByVal e As System.Windows.Forms.KeyEventArgs) _
[code]......
Null Reference With An Interface?
Mar 21, 2011I have a null reference warning. Dummy code as follows:
Dim poo As IEnumPooTypes
Toilet.GetPooInBowl(poo)
The variable 'Poo' says it may result in an object reference not set error but I cannot use the 'New' keyword with an instance. How do I make the warning go away?
Why Null Reference Exception
Jun 27, 2012visual 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]
View 1 RepliesXML Null Reference Error?
Jan 4, 2010Im trying to write code that will insert 'records' into an xml file, but everytime i click the button to make the changes to the XML file, it throws a null reference exception, ive gone through this code must be 100 times and cannot find what needs to be declared as 'new' as i know nodes can't be 'new' and the doc is 'new'
Imports System.Xml
Public Class frmuseradmin
[code]......
Asp.net - Function Chaining Depending On Boolean Result
Jun 7, 2010This is just an efficiency question really.. I'm interested to know if there is a more efficient or logical way that people use to handle this sort of scenario.
In my asp.net application I am running a script to generate a new project my code at the top level looks like this:
Dim ok As Boolean = True
ok = createFolderStructure()
If ok Then ok = createMDB()
[Code]....
I create a boolean and each function returns a boolean result, the next function in this chain will only run if the previous one was successful. I do this because an asp.net application will continue to run through the page life cycle unless there is an unhandled exception and I don't want my whole application to be screwed up if something in the chain goes wrong (there is a lot of copying and deleting of files etc.. in this example).
Pass A Delegate Into A Constructor Of An Abstract Class From A Descendant's Constructor?
Feb 15, 2010I have an abstract class which requires a delegate to function. I pass the delegate into the constructor. Now that I have a non default constructor I need to call the abstract class's constructors from the concrete class which means that I need to use MyBase.New(...). I have included a quick example below.
Public MustInherit Class BaseClass
Public Delegate Sub WorkMethod()
Private _Work As WorkMethod
[code]....
I have tried to do this but I keep getting the following error: "Implicit reference to object under construction is not valid when calling another constructor".Can I not do what I am trying to do above? I initially had the delegate setup in its own setter method. But then I am creating a deceptive API because it does require a point to a method to work properly.
.net - Null Reference Exception DNN Core 5.6.3
Jul 26, 2011My 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)?
.NET - Null Reference Exception Was Unhandled
Mar 7, 2011I 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]....
Asp.net - Net Null Reference On Database Connection?
Jun 13, 2012I know I'm being an idiot here and I just can't work it out. But i'm trying to take some data back from a vb.net database. It's falling over with a Object reference not set to an instance of an object error. And before the code runs it's saying the variable is being used before it's set, but I can't see how. Code:
Private taNotifications As dsDataTableAdapters.NotificationsTableAdapter = New dsDataTableAdapters.NotificationsTableAdapter
Dim notification As dsData.NotificationsDataTable = taNotifications.GetDataByClientID(userrow.UserID)
If notification.Rows.Count > 0 Then
Dim notificationrow As dsData.NotificationsRow
Dim forwardURL As String = notificationrow.ForwardLocation
End If
It falls over on the Dim forwardURL As String = notificationrow.ForwardLocation
C# - P/Invoke On X64 Null Reference Exceptions
Feb 24, 2010P/Invoke on x64 null reference exceptions, I get null reference exceptions when I try to compile for x64 in .NET code that makes use of platform invocation services to call unmanaged code in dlls. Am I missing something obvious here?
[Code]
Getting A Null Reference Exception W/program?
Jul 19, 2009I 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]...
Getting Null Reference While Reading From A Cell
Nov 21, 2011I'm having this exception while trying to get the value of a cell from a table.[code]...
View 2 RepliesIf Not Obj Is Nothing And Obj.IsActive Then // Null Reference Exception?
Oct 23, 2009If 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...
View 2 RepliesNull Reference Exception In Sql Transaction?
Apr 4, 2011i 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]...
Null Reference Exception On Debug?
Sep 13, 2010Now, 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]...
Null Reference Exception Unhandle
Feb 21, 2012I'm currently taking a VB class and i'm having trouble running my program properly.[code]
View 3 RepliesNull Reference Exception Was Unhandled?
Jun 9, 2011started 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]...
Null Reference In Lambda Max Count?
Oct 5, 2011Public Class Inventory
Public Property Productcode As String
Public Property lstattribute As List(Of Attribute)[code]....
I have a list of inventory items.I am trying to get the max count of attributelist in the inventory list .I used this code
oLsInventory.OrderByDescending(Function(c) c.AttributeList.Count).FirstOrDefault().AttributeList.Count
But if my attribute list null. The lambda throws null reference.Is there any way to check for null reference in lambda ? Or is there a better way to rewrite the above linq query ?
Object Null Reference Exception?
Feb 10, 2010write know i am gettin null reference exception due to followin code
Imports System.Xml
Imports System.IO
[code].....
System.Null Reference Exception?
Jul 13, 2010in 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...]