Adding To A Currently-null List (Of Object)
Aug 5, 2011I am not sure what I'm doing wrong, but I need some guidance from people smarter than me...
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Why Is List.add() Adding Items To Object AND Source Object As Well
Jun 15, 2011I need to be able to add elements to a copy of mylist.testlist without modifying the global mylist object. (Which seems to be happening via the below code.)When I am working on x, which should be a totally separate object, mylist is getting modified as well. How can I fix this? I have worked with lists extensively and never seen this behavior before. I have tested and reproduced the problem in .NET 3.5 and .NET 4.0 on Win 7 Pro 32bit.
Source Code:
Public Class Form1
Public mylist As New test
Sub Main()
[code]....
VS 2010 "Object Reference" Error When Adding Object To List (Of T) Property
Apr 25, 2011I have a class that has a property that I declare like this:
VB.NET
Private _DirectoryList As List(Of FileDirectoryInfo) ''' <summary> ''' Array of directories. ''' </summary> ''' <value>Object</value> ''' <returns>Directory array list</returns> ''' <remarks>N/A</remarks> Public Property Directory As List(Of FileDirectoryInfo) Get Return _DirectoryList End Get Set(ByVal value As List(Of FileDirectoryInfo)) _DirectoryList = value End Set End Property
[Code]...
Adding Items To A List (of Object)?
Mar 28, 2010I have some code that adds items to a List(of Object).
Here's my original code
Dim BeaconStoryList as New List(Of My.StoryType)
Dim BeaconStory as New My.StoryType
Dim NewStories() as New Foriegn.StoryType = GetStories
[Code]....
But as soon as the code assigned "Chicken" to BeaconStory.Title, then BeaconStoryList(0).Title would also change to "Chicken".
With my second version of the code this did not happen.
It's as though it was placing pointers into the elements of the array rather than values. If that is the case, however, then why does my second version of the code work - I'm still passing in the same thing - aren't I?
NullReferenceException Error Adding Object To A List
Jun 20, 2012I'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."
View 4 Replies.net - Adding New Object To Generit List Overwrites Previous Values?
Jul 15, 2010I have a problem with a generic list, which consists of intances of a class i created. I am just amazed, each time I add a new object to the list, it overwrites the previous entries. Here is a code sample, i just can't beleive it. I am using visual studio 2010:
Dim translations As List(Of TranslatedValue) = New List(Of TranslatedValue)
If Session("ctlTexts") Is Nothing Then
Dim reader As IDataReader = DataAccessFunctions.db.GetDataReader("SELECT [ControlID], [ControlTextEN], [ControlTextDE], [ControlTextBG] FROM [dbo].[tbLanguage]", GetConnectionString)
[code]....
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))
SQL Exception (adding A Null Value To A Non-null Column)
Aug 12, 2009When I put a break point to the last if clause in the sub ("If (backOrder < 0) Then", see below) it runs until the break point, if I put the break point further below, I get the following error:
Cannot insert the value NULL into column 'OrderID', table 'WHM.dbo.OrderDetails'; column does not allow nulls. INSERT fails. The statement has been terminated.
I've discovered first hand that it only happens when prodqty is bigger then qtyOnStock, thus executing the if clause.
The code:
Private Sub NCOSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles NCOSubmit.Click
Dim sqlText As String = ""
[Code]....
VS 2008 Adding Class Object To List Or Array In A Different Class
Jun 21, 2010I am trying to create an list or an array of a class.Here is my "Ingredient" class that I am trying to create a list of:[code]In my "recipe" class, I am want to create a list (or array) and I am drawing a big blank on how to do it. Can anyone point me in the right direction?
View 2 RepliesList Of T Find Date Or Other Property In A Object In The List - Then Return Found Object?
Sep 3, 2009After reading all the examples for list of T exists and Find and find first, none show how to handle multi-property objects. Below is bare bones example maybe someone could flesh out to show how this should be done.
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim DatePriceList As New List(Of DateAndPrice)
DatePriceList.Add(New DateAndPrice(Date.Parse("1/1/2000"), 10.12))
DatePriceList.Add(New DateAndPrice(Date.Parse("1/2/2000"), 11.12))
[Code]...
Passing Null Object() ByRef Returns Initialized Object()?
Dec 8, 2009I 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.
[Code]...
VS 02/03 - System.Null ReferenceException: Object Reference Not Set To Instance Of Object
Dec 14, 2010Currently 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]
View 4 RepliesDisplay A List (Of Object) Which Has Single Objects And Child List (Of Object)?
Sep 6, 2011Limited to using v2.0 of .Net framework (we use VB.net) due to environmental constraints on our servers.I've got an ASP.net webpage which pulls data from a webservice that performs checks on user accounts in active directory. Operators can check multiple accounts at one time using the web interface. The webservice returns a list(of AccountCheck) objects which themselves contain single properties like username, email address, and List(of AccountError) objects which contain multiple properties.[code]What I want to do is using some kind of repeater, create multiple panels or divs which contain labels showing the username, email etc, and a gridview which has the accounterror list bound to it to show all the errors. The users could be checking 2, 5, 7 accounts at once, and is dynamic.
View 2 RepliesCast A List Of Object To List Of Interface That Object Implements?
May 19, 2009I am working in VB.net and have a Class, Foo, that implements an interface, IBar.I have a List of Foo's, but I need to pass a list of IBar's into a function, but I keep getting casting errors, even when I use DirectCast.My code is [code]MainWorks works, but it would be really annoying and inefficient to have to do that everywhere I want to call this function.
View 4 RepliesWord 2007 Adding Adding Values To Combo List Box
Jun 7, 2011I am trying to create a simple Word doc that when the user presses the button it takes the information in the boxes and tosses it into a template style paragraph. But my issue is that I have two combo list boxes as seen in the picture. I want to have two values in the drop down list as seen in the labels next to them but for the life of me I can't figure out how to do this in Word 2007. In Visual Studio this is much easier but I am work and need to snap this out for the folks at work. Is there an option that I can choose in the properties where I type in the values for each drop down or do I have to add them in at run time?
View 1 RepliesHow To Quickly Transform A List(Of Object) Into A List(Of "Object.field")
May 29, 2012Suppose I have a list of Cat.
Public Class Cat
Public Property id As Guid
Public Property name As String
Public Property race As catRace
End Class
How can I quickly transform this List(Of Cat) into a List(Of Guid) using the id property?
I could do :
Dim newList As List(Of Guid)
For each item in catList
newList.Add(item.id)
Next
But I think there must be a way to do this faster (1 LOC). I just can't find how.
List.count While Adding Items To The List Increments Returns 0
Jul 20, 2011I am attempting to read the results from a SQL query into a List(Of) and I can see the List.count while adding items to the List increments, however in another part of my code when I am attempting to read the List the List.Count returns 0. My List is as follows:
[Code]...
.net - SyncLock On Null Object
Mar 25, 2011Is there simple way to SyncLock an object that can be null? And before you ask for it, yes, I know that it isn't logical to perform a SyncLock on a null variable. However, that would simplify my code because right now, I have no choice but to perform a null check all over the place before calling a SyncLock.
[Code]...
Check To See If Object Is Null
Jun 29, 2009I 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]
View 2 RepliesSet Value Of PARAM Object When It Can Be NULL?
Oct 26, 2010If I have a variable, X, of type SqlDecimal, that was instantiated without providing a decimal value parameter to the constructor, then the .IsNull property is True: Dim X As New SqlDecimal '.Value = Null..If I have a Stored Procedure that acepts a single parameter, @SqlDecimalParameter, of type Decimal, the value of this this parameter could be NULL or a decimal value. This is how I would normally call the stored procedure:[code]It seems like the 1st example should work. Am I missing something? after all, the Sql datatypes are designed to work with SQL Server, I thought.[code]I get the following error:Failed to convert parameter value from a SqlDecimal to a Decimal.It works when X.IsNull is True.How do you set the value of the PARAM object when it can be NULL?
View 1 RepliesHttpResponse Object Null Error
Nov 15, 2011MVC 3. VB.NET I have the following controller action in my application to send generated PDF files to the User by download. The function works fine when the controller itself has been invoked. But when I call to the function from outside the controller it returns a " Object reference not set to an instance of an object " error as soon as it hits the response.contenttype line. I have verified that all of the variables are in fact making it to the below action.[code]any ideas why this is only working when called explicitly from inside its containing controller???
View 2 RepliesObject Null Reference Exception?
Feb 10, 2010write know i am gettin null reference exception due to followin code
Imports System.Xml
Imports System.IO
[code].....
C# - WCF Serialization And Interfaces - Error: List(of Object) Cannot Be Converted To List(of IMyInterface)
Oct 16, 2009Does link text mean I have to return a concrete implementation? Even though I am using svcutil with the /r that includes my entites(where IMyInterface is defined). I get no errors but it changes all List(of IMyInterface) to list(of Object) and I cannot deserialize it on the client
Error: list(of object) cannot be converted to list(of IMyInterface).
.NET - NULL Object If Assigned String Length Is 0?
Jul 12, 2010Currently, whenever I pass a string to the db, if that string is empty, then i set that object to NULL by doing the following:
IIf(DescriptionTxt.Text.length > 0, DescriptionTxt.Text, DBNull.Value)
I was thinking about writing a function to reduce the length of this code, and make it more consistent.However, I was wondering, is there already a way of doing this in .NET 3.5?
C# - Set Custom Object To Null In The Dispose() Method?
Feb 17, 2010Is there any sense to set custom object to null(Nothing in VB.NET) in the Dispose() method?Could this prevent memory leaks or it's useless?!Let's consider two examples:
public class Foo : IDisposable
{
private Bar bar; // standard custom .NET object
public Foo(Bar bar) {
[code]....
Does An Object Retrieved From A List Get A Copy Of That Object Or A Reference To It
Feb 1, 2012In VB.net, when I retrieve a value from a list do I get a copy of that value or a reference to it?
dim blah as someObject
dim listOfBlahs as list(of someObject)
listOfBlah.add(new someObject(1))
[Code]....
Create List Of Child Objects From List Of Parent Object?
Jun 2, 2011I would like to create list of child objects from list of parent object. Like If i have list of bookingroom which has one member room then i would like to create list of room from it.
eg. code:
Dim BookingRoomList As List(Of BookingRoom) = New List(Of BookingRoom)
Dim RoomList As List(Of Room) = New List(Of Room)
BookingRoomList = BookingRooms.FillGrid()
[Code]....
Is there any short cut method instead of iterating over for earch?
Copy List Object To Another List Object
Jun 15, 2012I am having a problem when setting VB.NET list object to another.I create an instance on ReadLocations and than create an object of ReadLocation where then I loop through ReadLocations and set ReadLocation1 equal to rl. What happens is that if I then go and change ReadLocation1 to something else (assdfhsd) it will also change the ReadLocations index. I am really confused why it would be doing that unless it is "=" sign means referencing instead of actually setting the value. Please help as I am a C# developer but the program I am modifying is in VB.NET.[code]
View 1 RepliesCheck Object's Property For Null Or Empty String?
Jul 28, 2009I'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
[Code]....
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?
Error: Null Reference Exception Was Unhandled-object
Jul 8, 2009i 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
[code].....
