Every Nth Item In A Collection In .Net?
Dec 16, 2009Nearly identical to How can I get every nth item from a List<T>?But I'm having trouble turning
List<T> list = originalList.Where((t,i) => (i % 5) == 0).ToList();
Into VB.Net code.
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How To Find Item In Collection
May 17, 2011I have created collection and adding values in the collection, later I need to find if uer passed value is exist in the collection or not, I use contains finction to find the answer but it always returns false even though user passed value exist in the collection list. here is my code:
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Item Cannot Be Found In The Collection Corresponding?
Aug 17, 2009This is my code.Private Sub cmdDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdDelete.Click
[Code]...
Know If Iterating On The Last Item Of The Collection?
Dec 26, 2010I want to do something different on the last KeyValuePair of the Dictionary I'm iterating on.
For Each item In collection
If ItsTheLastItem
DoX()
[code].....
LINQ To XML, Only Can Get First Item In Collection?
Sep 8, 2010Here is an example of my xml doc:
<?xml version="1.0" encoding="utf-8"?>
<employeedata>
<employee>
<firstname>Bob</firstname>
<lastname>Anderson</lastname>
[Code]...
However, only the first phone number (Office) displays in the listbox. The phoneinfo collection has both <phone> elements, but the For Each statement doesn't seem to iterate thru.
Removing An Item From A Collection?
Oct 14, 2009Is there a way to remove 'this' item from a collection, i.e the one I'm working with, or do I always need an index?
For each ThisItem in MyCollection
if a=true then MyCollection.Remove(ThisItem)
next
[code].....
Track Item Within A Collection On WP7?
Jan 30, 2011I'm building a WP7 (VB.NET) app and have a custom class, PinInfo, of which I have two ObservableCollections, TempPins and FavoritePins.
In various parts of the app, I need a unique identifier to get a reference to a particular PinInfo in the collection, so at present, I assign an ID to the PinInfo when it's added to the collection, then later get a reference to the pin via the ID.
For example, if I create a button to delete a pin, I set its tag to the pin's ID, then the button click handler reads the button's tag to get the corresponding pin from the collection (via LINQ).
I generate the ID by adding one to the last-assigned ID, but these lists are often modified (i.e. items removed), so I end up with needlessly large ID numbers (e.g. just a few items, with IDs in the thousands).
.net - Linking Ranges To Item In Collection?
Aug 17, 2011I have a collection as such
Private Shared ReadOnly thermoPaths As New ReadOnlyCollection(Of String) _
({
"thermometer_000_108x320.jpg",
"thermometer_010_108x320.jpg",
"thermometer_020_108x320.jpg",
"thermometer_030_108x320.jpg",
[Code]...
Collection Item Changed Index?
May 15, 2009Is there any way to get the index of the changed item? I couldn't find any examples.
View 1 RepliesSearch For An Item In Collection Type?
Nov 10, 2011I am using VB .NET 1.1 and wanted to make sure if inside a key value pair class "Dates" (collection type) a key by name "TerminationDate" exists.
If Not Dates.Item("TerminationDate") Is Nothing Then
'Do x y z'
End if
But this is throwing an exception: Argument Index is not a valid value.
Get Index Of Item In Collection That Raised Event?
Jun 30, 2010In a list of timers, how do I determine the index of the item that elapsed without having to iterate the collection as shown below (e.g. can I pass a paramater to OnTimedEvent, or can the collection raise an event to say which item fired???). It's the individual timer index that I need as I'm using it to refer to something else.
(I wont know how many items I'll have in the list in advance so I can't create an individual event handler for each timer - I don't think I should even if I did).
Public Class Form1
Private _timers As New List(Of System.Timers.Timer)
Private Sub Form3_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
[code]....
LINQ - Select A *TYPED* Item In A Collection?
Mar 1, 2011Can I use LINQ to return an item in a collection that is the same TYPE as the items in the collection? I am a LINQ Noob trying to avoid looping.
Dim mostRecentlyCreatedQuestionnaire As ParentQuestionnaireItem =
CType((From P In questionnaireCollection Order By P.Metadata.CreateDate Descending).Take(1), ParentQuestionnaireItem)
I get an "unable to CAST" error when I include the CTYPE function. I kind of expected that error, but I imagine that if I coul dnot do this, LINQ's usefulness would be diminished and therefore assume that there must be a way..
Add Item To System.Collections.Specialized.String Collection When It Is Not Already There?
Dec 29, 2010How can I have it so that you can add items to a System.Collections.Specialized.String Collection but only if it is not there already? I have already found the code, but deleted it and cannot remember it. It is something like[code]....
View 9 RepliesDelete An Item From A Collection That Is Data Bound To A GridView?
Jul 22, 2011I am creating a simple website using the language of VB.NET, I am having trouble with one part at the moment and could really use some help.
At the moment I have items that are stored in a database, when the homepage loads these items are added to a Gridview which allows the user to select the items they wish to add to their shopping cart. Once an item is selected from the gridview it is added to a collection. That collection is then added to a Session. This is the code I have for completing that task.[code]...
Item Collection Of The ListBox1 Is Stored In A Text File?
Feb 15, 2010I want to create a very simple database. form1 - ListBox1, textBox1, buttonadd, buttonremove. The item collection of the ListBox1 is stored in a txt file along with a string that will be displayed in the textbox1. the file will look like this ( like a .ini file):
[Code]...
Linq - Select Single Item From Child Collection?
Jan 12, 2012I have a parent child collection objects and was wondering how to get a single item from the child collection using Linq
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VS 2008 Return Listview Item Collection In Multithread?
Aug 31, 2009I am doing this within a thread:For Each item As ListViewItem In lvUsers.Items and I am getting: Cross-thread operation not valid: Control 'lvUsers' accessed from a thread other than the thread it was created on.I have been able to adjust a control in a way using something like:
Public Delegate Sub ListAddNameInvoker(ByVal text As String)
Public Sub ListAddName(ByVal text As String)
If lvUsers.InvokeRequired Then
[code]....
But how do I get data from a control and pass it to another thread?
VS 2005 : Make A Comboxbox List The First Item In The Collection By Default?
Nov 25, 2009How can I make a comboxbox list the first item in the collection by default in other words i have a collection list
1
2
3
4
5
When program loads I want combobox to load 1
VS 2008 Data Send To One Item In A Collection Is Changed For All Items
Jul 30, 2009I have a class that contains a collection of another class. See below
Public Class Spot
Private mActive As Boolean
Public Sub New()
[Code]....
Reciept Printing - Form Which Consist - Item Code , Item Name , Item Price , Quantity Of Item
May 25, 2012Regarding my college project. i'm working on a sales system . i have a form which consist of all the following information( item code , item name , item price , quantity of item ) which is display using a data grid . data input by user using text box and all this information will be stored in a database(sales database) i'm using ms access 2007. the grand total will be displayed in a text box . and amount paid will be input in a text box too , my major problem now is how to i create a reciept that will have all this information of the purcase. i have a reciept button . what the next step ? i dont have any idea how to get the reciept done.
Imports System.Data.OleDb
Public Class Form5
Dim con As New OleDbConnection
[CODE].......................
Automatically Recognize And Handle Changes Of An Item In A "System.Collections.ObjectModel.Collection"
Feb 4, 2011I wanted to create a custom control with a custom Item-Collection in it.(Similar to the ListView Items, but with other properties)I wrote a Class that holds properties of a single Item data (ClassItemData) and another class that "Inherits System.Collections.ObjectModel.Collection(Of ClassItemData)". The Collection class contains a public event (ItemCollectionChanged) which is raised when "ClearItems", "InsertItem", "RemoveItem" or "SetItem" is called. (I used "Overrides" on all these functions and added the Raise Event to them.) The event is handled in the custom control itself and causes the control to refresh/repaint itself. The collection class contains also "Default Public Overloads ReadOnly Property Item(ByVal index As Int32) As ClassItemData" which returns the Item at the speciefic index.
The control refreshes itself when I place the control on a form and use code like: ControlName.Items.Add("TestItem") Unfortunately the control does not refresh itself when I use: ControlName.Items.Item(0).Visible = False The value of the Item itself has changed after this, but the control does know about the changes and does not refresh itself. If I do a manual repaint/refresh of the control, it looks all fine, but it does not work automatically. Does anyone know, what I have to add, so I can handle an event or something in the control when a property in the ItemData class has changed? How do I recognize changes in existing items and raise an event in the custom event?
.net - Storing Subcollections (filtered Versions Of The Main Collection) Inside The Collection As Cache?
Jan 15, 2010Is it good practice to store sub-collections of item X inside a parent collection of item X for caching 'filter-queries' which are performed on the parent collection? (They won't be used together (as in color AND type).) Or is it also ok to just Loop over the collection and return the correct entities in a temporary collection?
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C# - Edit List Collection : Error Note Collection Was Modified - Enumeration Operation May Not Execute?
Sep 7, 2011I have the following classes:
Product, Service and OrderItem
Product and Service must inherit OrderItem. So basically I want to store OrderItem object in my shopping cart and these object are store in a list.
Public MustInherit Class OrderItem
Private m_enuItemType As TypeOfItem = TypeOfItem.None
Private m_strUserID As Integer[code].....
Make A Custom Collection That Take Advantage Of The Collection Editor?
Feb 8, 2010I have been researching for a couple of days now and to no avail. Does Anyone know how to make a custom collection that take advantage of the collection editor? I would like to be able to have 3 Color Values, 1 Boolean and 1 String.
View 15 RepliesPossible To Make List Box Item Height For Item Depending On Amount Of Lines That Item Contains?
Jan 1, 2012I have a list box on the form which functions as a copy/paste. When you copy something, it is automatically added to the list box as a "clipboard helper". Here is the problem,however: if the text is more than 1 line, the list box does not show all the text.It ends up looking messy.So getting back to my question, is it possible to make the list box item height for an item depending on the amount of lines that item contains?This is a one line sentence in the list box and should take up one line.This is a multi line sentence in the list box and should take up two lines for item height.
View 11 RepliesWhen Users Select Each Item Another Item Will Be Added To Second Listbox But It Is The First Selected Item
Jul 5, 2010In my application I have a listbox and SelectionMode should be MultiSimple because users need to see which items they selected. In another tab we have another listbox this one should show all the selection users had done in first tab. Private Sub
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.net - Collection Initializes For Read-only Collection Properties?
Jul 25, 2011I'm trying to support Basic.NET on my framework so I'm trying to convert C# 4 code to Basic.NET 10. Microsoft is committed to "co-evolve" these two but I'm having a problem with collection initialization... I found that I can initialize a collection much like in C#:
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.net - Search The Collection Of A Collection In LINQ Where Clause?
Apr 15, 2009I've got the following ADO.NET Entity Framework Entity Data Model:I want to find all the Policyholders with both a Service of a given Id and also a Keyword of a given Status.
This LINQ Does Not Work:
Dim ServicesId As Integer = ...
Dim KeywordStatus As Integer = ...
Dim FoundPolicyholders = From p As Policyholder In db.PolicyholderSet.Include("Keywords").Include("Services") _
Where p.Services.Id = ServicesId _
And p.Keywords.Status = KeywordStatus _
Select p
The Where clause cannot search the p.Services and p.Keywords EntityCollections in that way.
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Accessing And Adding Items To A Collection That Is In A Collection?
Apr 6, 2012currently in my application I have a Global Collection that is a Collection of Collections.Currently I am trying to add items/ elements to one of the child collections of the Global Collection but I am unable to use the collections methods of the child.When I assign a variable to the child collection and return the collection it is just an object with the collection inside.
Ex:
Dim GlobalCollection as New Collection
Dim ChildCollection1 as New Collection
Dim tempCurrentCollection[code]......
Collection Index Must Be In The Range 1 To The Size Of The Collection?
Dec 17, 2009I've been working with a CMS called InsiteCreations 2008. I'm running into an error I just can't wrap my head around. I would even be willing to compensate anyone a small amount over paypal, for a solution. The error is rare in occurance, and appears when clicking about 3-4% of links to other pages within our CMS.The full code page is quite large, but there seems to be only one function associated with the error. The error also only appears when not logged into the CMS. If logged into the CMS, clicking the link simply displays the page as normal. I have already checked permissions on the page from the CMS admin console, and it is public.
The error message is as follows:
Server Error in '/' Application.Collection index must be in the range 1 to the size of the collection.
Description:
An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
[code]....