Sorting Objects In Arraylist By One Of The Object's Properties?

Aug 30, 2011

I have a group of objects stored in an arraylist. These custom type objects have a number of properties from their underlying class . I want to use one of the properties to sort the array. I cannot determine which Array.Sort method to use.

I want to sort based on an integer property. Virtually every example I can find involves sorting strings.

So, assume the Objects have the following properties.

Obj.name as string
Obj.ID as integer
Obj.Alive as boolean

The objects are kept in an arraylist called FriendsOfMine.

I want to be able to order the list by Obj.ID, both ascending and descending in value.

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Code Sorting An Object Within Arraylist ?

Oct 12, 2009

Class Murid
Implements IComparable
Public strNama, strKelas As String[code].....

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Sorting A List Based On An ArrayList Within A Custom Object

May 24, 2010

I am using a list to keep track of a number of custom Row objects as follows:

Public Rows As List(Of Row)()
Row has 2 properties, Key (a String) and Cells (an ArrayList).

I need to be able to sort each Row within Rows based on a developer defined index of the Cells ArrayList.

So for example based on the following Rows

Row1.Cells = ("b", "12")
Row2.Cells = ("a", "23")

Rows.Sort(0) would result in Row2 being first in the Rows list. What would be the best way of going about implementing this?

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Implementation - Loop To Update Properties Of Each Object Of A Set Of Custom Objects

Jan 4, 2010

I am using a loop to update properties of each object of a set of custom objects. The routine knows which controls to update because the controls value is not empty, I don't want the routine setting the corresponding properties to nothing when the control is empty. Now I know how to do this perfectly fine with IF statements such as:

CODE:

But this feels really redundant doing that same IF block over and over for each property/control combination, I thought about creating a separate routine that takes the control as an argument and does all the repetitive IF blocks but I don't know how I could also pass an object property to tell the routine to update that particular property.

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ASP.NET Cast ArrayList Of Objects To Custom Objects?

Aug 9, 2011

getting the following error Unable to cast object of type 'System.Object[]' to type 'OrderService.webdirect_WebLinesRow[]'. On the line

webdirect(web_companyID, web_locationCode, web_customerNumber, web_orderNumber, web_orderReference, web_orderDate, webLinesArray.ToArray(), o_Company, o_LocationCode, o_CustomerNumber, o_OrderNumber, o_OrderStatus, o_OrdDescrip, webRespArray)

I created the webLinesArray.ToArray() array as such

Dim webLinesArray As New ArrayList()

Am I missing an additional cast or something ?

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Modifying Objects Inside For Each Loop Sets Properties Of All Objects With Values Of Last One?

Jan 29, 2011

I have a program like this.

Module Module1

Public Class Mstr
Public Property Prop1 As String
Public Property Prop2 As String[code]....

But it is not working as I expect it to. You can see it from.The DtlsB properties of all three DtlsA objects are having values from last iteration.

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ArrayList Sorting From Z To A (Descending Order)

Apr 13, 2010

Code:
Dim list As New ArrayList()
For Each item As String In l_input.Items
list.Add(item)
Next
list.Sort()
Ok this sort the list from A to Z alphabetical order but how do you sort in from Z to A, i.e. descending order. Summat to do with the comparer? I have no idea how to use the comparer. Or is there an easier way?

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Sorting/Splitting String In ArrayList?

Aug 20, 2010

Basically, Im running an SQL query to the database, which obviously returns data in their fields. What I want to do is add each record into an ArrayList and split the string based on fields. I.E

CustomerID,Surname,GivenName etc

How do I go about this? so far I have:

alstData.AddRange(sLine.Split(","c))
sLine = the record from the database.

This doesnt seem to work, it just display's the data in one line with no split such as 20205SmithJohn?

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Create An Arraylist Of Objects?

Feb 11, 2010

I use serializer classes for storing data and each class can hold an array of objects for the same class which is a key feature of the class. I declare this array as so:

myClassObjects(1000) as myClass

My question is- can I declare the array as an arraylist so I can sort and count objects in the array(list) quicker and easier and are there any drawbacks to taking this approach?

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Editing Objects In ArrayList?

Dec 31, 2009

1. how do you edit objects in an ArrayList? 2. the code below works ok but is it ok to obtain a reference to an object from an ArrayList and then edit the object?

Public Class Form1
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

[code].....

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Possible To Serialize Arraylist Of Objects Into xml?

Feb 27, 2009

Is it possible to serialize an arraylist of objects into xml?Its damn urgent.Kindly reply.

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Catching Events In ArrayList Of Objects

Jul 22, 2009

I have an ArrayList that is populated with Objects. These Objects raise events at certain times. How can I capture these events from the ArrayList? i.e.
I want something like this:
Public Sub MyRaisedEvent(ByVal obj as MyObject) Handles MyArrayList.MyEvent
End Sub

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Passing An Arraylist Of Objects From One Class To Another?

Aug 19, 2011

I have the following code in Class B

FolderList.add(FolderCategory)

when i do a count it display a list of 25 items in the folderlist.Now i have a main class when i tried to use the following method

Dim MainClass as New ClassB

Console.writeline(MainClass.FolderList.count()) the value reflects as 0 items meaning is empty.i need to retrieve the arraylist from Class B using the MainClass to retrieve those items inside the arraylist.

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Retrieving Data From Arraylist Of Objects?

Jun 30, 2009

I am trying to retrieve the correct value from an ArrayList of objects (.NET 1.1 Framework):I have the following defined:

Public AlList As New ArrayList
Public Class ItemInfo
Public ItemNo As Int16

[code].....

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VS 2008 - Error With Arraylist In My.Settings - Object Reference Not Set To An Instance Of An Object

Mar 14, 2010

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")

[CODE]................

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"?

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Flattening An Object Hierarchy Using A Shim Class - Initializing Derived Object Properties From The Base Object?

Jul 10, 2010

I am somewhat new to object oriented programming and am attempting to flatten a Linq object hierarchy by using a shim class.how to initalize a derived class with property values from a base class?I have two objects, a base object with about 100 properties, and a derived object which inherits from the base object and adds a few additional properties beyond those of the base object. My simple constructor creates the derived object, but I am looking for a way to initialize the derived object properties with values from the base object.Right now I am using reflection to iterate over the properties individually and I suspect there may be a better way. The following example shows my shim class constructor for the derived class, and two properties:

newProperty1 - a new string property of the derived class

flattenedProperty2 - a new string property of the derived class, copied from a 2nd-level object of the base class

Code example:

Public Class derivedObj
Inherits baseObj
Private _newProperty1 As String[code].......

Is this the correct constructor approach to flatten the object hierarchy using a shim class? My second question relates to initialization of properties in the derived class. The constructor above creates the derived object, but what is the best way to initialize the derived object properties with values from the base object? The following code uses reflection to iterate over the properties individually, but I suspect there may be a better way.

Code example:

' property names are in the string array fieldNames

'baseObjQuery is an ienumerable of baseObj

'derivedObjList is a list of derivedObj[code].....

Is there a simple way to initialize values for the properties in the derived object based upon the values of the common properties in the base object?

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Arraylist Of Objects, Listbox1_SelectedIndexChanged, And Linking Values?

Nov 6, 2010

I'm completely new to VB.NET and this is likely a few steps over my head, but have managed to get myself this far with just Google.I'm reading an XML file and creating an arraylist of classes for the values in there, as seen:

Public Class yresults
'Dim xdate As XmlNodeList = xDoc.GetElementsByTagName("Date")
'Dim link As XmlNodeList = xDoc.GetElementsByTagName("Link")

[code].....

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Sort ArrayList Of Custom Objects By Member?

Sep 3, 2009

How can I sort an ArrayList of custom objects by public member? Example,If I have a list of article objects, and I'd like to sort the list by the rating member after I've filled the ArrayList

Public Class Article
Public bulletin As String
Public rating As Integer[code].....

Now I'd like to sort uniqueArticles by rating and print articles by rating order.How do I do perform that sort?

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Use ISerializable Interface To Serialize An Arraylist Of Objects?

May 10, 2009

I have a class called Tree, it has an arraylist called alTreeNodes. alTreeNodes is an arraylist of TreeNode class. Since I am using ISerializable Interface, I have to provide a specific constructor. I know how to write it for string parameters such as name_value, but how should i do with arraylist of object then? See "???" in the code blog before.

Protected Sub New(ByVal info As SerializationInfo, _
ByVal context As StreamingContext)
If info Is Nothing Then

[code]....

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Have Multiple Threads Run Through An Arraylist Of Object And Process Each Object?

Apr 30, 2009

I am trying to have multiple threads run through an arraylist of object and process each object. My problem is that each thread processes every object in the array.So they are not working together on the job. I made sample application to show my problem. I think the problem is somewhere in my ThreadSub() Here is the

Imports System.Threading
Public Class Form1
Dim myitems As New ArrayList

[code]....

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Random Objects - Let The User Input Objects To A Richtextbox 1 Object On Each Line?

Jan 6, 2011

I want to let the user input objects to a richtextbox 1 object on each line, and somehow use Random.Next to select pseudorandomly a few objects, the number 'few' inputted in a textbox.

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Sorting A List Of Objects?

Mar 16, 2012

Suppose I have:

Public Class myClass1
Dim foo As String
Dim bar As String

[code].....

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Forms :: Objects - Cycle Through A Arraylist And For Each Item In That List

May 15, 2009

I want to cycle through a arraylist and for each item in that list I need to create a picturebox, label1, label2 each with specific name attributes

[Code]...

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Game Programming :: Control Objects Separately In An Arraylist?

Apr 4, 2008

After going through some tutorials I set out to work on my own game. Right now it's simple, I have a ship that moves left, right and shoots. I also have Asteroids that fly at the ship.

The problem is that I have 3 asteroids in an array, and they all act the same... I would like random speeds and directions.

here is what I have in relevant code:[code....]

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Forms :: Handling Events From WebBrowser Objects Contained In An ArrayList?

Jul 18, 2009

I'm writing a tabbed web browser for someone who is learning VB.NET, and I have got to the point where I can add/remove browser controls into tab pages, controlled by one set of buttons on the main form, but I can't handle events from the WebBrowser objects.I have tried this but it says that 'DocumentTitleChanged' isnt an event of 'Control'...

Dim browser As New ArrayList
browser.Add(New WebBrowser)
browser(0).parent = TabControl1.SelectedTab
browser(0).dock = DockStyle.Fill
AddHandler browser(0).DocumentTitleChanged, TitleChangedHandler()

I want to update the tab title with the web page title when it changes. I started using a timer to update the tabs but there must be a way to add an event handler here.

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VS 2010 : Sorting LinkedList Objects As They Are Added?

Oct 22, 2009

what the point of a Generic.LinkedList is in Visual Basic .NET 2010.I've heard that I can save sorting time with such a list, since it somehow sorts objects as they are added.How can I perform such sorting with this type of list?

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Sorting A Class Of Multiple Properties?

Oct 13, 2011

I have created a Class, basically like this:

Public Class Person
Implements IEquatable(Of Person)
Public Sub New(ByVal Name As String, Optional ByVal Like As Boolean = True)
Me.Name = Name

[Code]...

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Sorting A List(Of FileInfo) By 2 Properties?

Oct 3, 2011

I have a List of FileInfo objects that I want to sort by creation date & file size. Is there a way to do that?

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Add Object To Arraylist?

Oct 11, 2011

I'm having some trouble adding an object to an arraylist.

Basically the object has two properties (file id/name), but I can't figure out how to assign those properties. During runtime it errors out with public member on the object not found.

Private QueueList As New ArrayList
Public Sub Queue(ByVal FileName As String, ByVal FileID As Integer)
Dim QueueObj As New Object

[Code]....

I'd also like to know how I can do a loop on the arraylist and access the two properites on each record.

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VS 2010 Sorting A Listbox (after Trying To Copy Class Instances Properties To A Temp List)

Jan 25, 2012

I'm trying to figure out a way to sort the entries of a listbox... but in a different way instead of the obvious one (sorted property). First of all, I need to explain how the items are populated at first:

[Code]...

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