Use List(Of T) In VB Instead Of ArrayLists?
Jan 30, 2011
I have been tempted to use List(Of T) in VB.NET instead of ArrayLists by someone-who-must-not-be-named-Robinson.Essentially, what I need to store are three things: One string, two integers, and maybe two booleans. I liked using ArrayList, because it treated all its elements as "Objects" so I didn't really have problems storing that variety of elements.But now I have been thinking on using List(Of T). But how do I do to store that variety of elements of mine? I have been thinking on making a Structure holding the five elements.Sounds like a good idea? I heard somewhere that Structures are expected to have a short life. But I fear I will be having my structures for... forever, as long as my app lives. That makes any difference? Finally, what if I needed to create... dunno...... 125000000 Lists, each containing a structure? Is that possible (and good)?
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Jul 12, 2011
I am obviously not understanding something about scoping that is very basic. I have a very simple class:
Public Class testListClass
' This just contains a single list that is set by a property or the constructor
Private classArrayList As New ArrayList()
[code].....
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Jul 2, 2010
I have two arraylists, and I would like to have a new arraylist with only the uncommon items. Is this the "best" or at least decent way to do it?
[Code]...
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Jun 23, 2012
OK, so I am creating a bit of code that will allow me to randomly pick one "card" from a "deck", delete that "card" from the deck, and repeat. I found in all of my research that vb.net has the arraylist that is supposed to be very simple in these situations. However, when I try to populate them with a For Each statement, I only get odd numbers in the array list. What am I missing?
Dim a As New ArrayList
For i As Integer = 1 To 52
a.Add(i)
[code].....
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Jan 5, 2010
I have two arraylists that contains links in one and the root url in the other. Sometimes the lists dont equal in number and I would like to iterate through the links list and if it contains a matching root url add it to a third list but also avoid any duplicates. I tried this but am not getting consistent results.
For Each link As String In urls
For Each part As String In post
If part.Contains(link) Then
[code]....
Perhaps there is another way; basically the part in post is a link to a page and contains the root url( which is link in urls). After extracting all these I need to ensure the 2 lists match.
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Mar 1, 2009
I was trying to use ArrayLists with My.Settings but I can't seem to figure out how to get them to work.If I make a setting called "Words" and make it an ArrayList without a value, the program has an error every time I try to run it. If I try to give it a value in the project properties window it always gives me an incorrect data type error. Besides, I don't want it to have a value, I want it to be blank such as when declaring a New ArrayList. The only way I can get an ArrayList My.Setting to work is by clicking in the Value box, clicking the "..." button in the corner and adding some kind of Object with the add button. This automatically puts some kind of wierd object in the first index of the array list. If I don't convert Item(0) of the arraylist to a string then it also gives me an error when I try to read it. As a string it comes up as System.Object. Even though I can use the my.settings.Words ArrayList with an object in the first index, how can I get the setting to start off blank without having to constantly avoid the first index?
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Oct 7, 2010
I have two array lists
dim Colors1 = New ArrayList
Colors1.Add("Blue")
Colors1.Add("Red")
[code]....
I would like to find out which colors are missing from Colors2 that are found in Colors1
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Sep 8, 2010
I have three arraylists (datasets and subsets) that I need to combine into one arrraylist so I can databind it to a repeater control and then present data to the user. As far as I know, you can only bind the repeater with one datasource (please correct me if this is wrong) that's why I'm combining these arraylists.Each arraylist has an ID from the database which I can use as a datakey to keep the data aligned. How do I combine these lists?
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Oct 28, 2011
I have searched high and low for a solution yet still no luck, I have two arraylists populate with FileInfo and I want to compare the two and write the duplicate (matching files) to a listbox.Here is how I have populated the arraylists but in terms of the comparison I have not found anything that works:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim arraylist1 As ArrayList
Dim arraylist2 As ArrayList
[code]....
What can I do next to compare the two and write the duplicates to ListBox1.
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Jan 5, 2010
I have two arraylists that contains links in one and the root url in the other. Sometimes the lists dont equal in number and I would like to iterate through the links list and if it contains a matching root url add it to a third list but also avoid any duplicates. I tried this but am not getting consistent results.
[Code]...
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Jun 2, 2009
I am trying to convert an algorithm to use them in order to save memory. However, I am struggling to achieve error-free code while using "Strict On".
Here is a basic version of the code I am attempting to use.
Code:
Option Explicit On
Option Strict On
Module Program
[Code]...
It works when I do not use the Strict option. How do I improve the code to compile error-free?
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Jan 30, 2010
Background: I'm writing a application that will allow users to enters items on a form using textboxes, radio buttons and checkboxes. I then take each input item and write it to it's own arraylist. After the user is all done entering data the information in the arraylists will write out to a single .txt file.
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Jan 5, 2010
I have two arraylists that contains links in one and the root url in the other. Sometimes the lists dont equal in number and I would like to iterate through the links list and if it contains a matching root url add it to a third list but also avoid any duplicates. I tried this but am not getting consistent results.
[Code]....
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Sep 26, 2011
I've got three arraylists of strings, and the "091: " part of the string is not part in the arraylist, thats added when I display them in the listboxes. So basically, how can I sort a list, and make sure that item nr 98 in english, still equals nr 98 in japanese and kanji?
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Jul 1, 2010
I did this before, but i totally forgot how to do it.I have an array, the array contains strings with 2 seperators.like so:
name1 / name2 / name3
Basicly i want name1, name2, and name3 in 3 seperate lists, or arraylists. But, i don't know how to do it.Each line is being read from a file.
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May 14, 2009
II am trying to create a toggle button that switches a list to a range and then back to a list if needed. I am able to get it to do both but when I add an item to the list, convert to a range and then convert back to a list it leaves off the last items I entered.I tried to work in a code to select all cells but I must not be putting it in the right place.This is what I have so far:
ActiveSheet.ListObjects.Add(xlSrcRange, Range("$A$3:$AE$7"), , xlYes).Name = _
"List1"
I realize the problem is the $AE$7 (the $A$3 is correct)
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Oct 27, 2009
In VS 2008, VB.Net, I am successful connecting to a local SQL Server (version 8) and seeing all tables/views/procedures in Server Explorer. The local OS is Win XP Pro SP3. I created an ODBC data source to a remote SQL server (also version 8) with a database of the same structure as the local one. The connection tests out ok. The remote computer runs Windows Server 2000 SP4. In the VS 2008 Server Explorer I add this ODBC source. When I click on the plus-signs to expand items, neither the tables nor the views show anything, whereas the full list of procedures appears. Is it the old SQL Server version? Is it the old Server OS version? Something else alltogether?
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Dec 30, 2010
This is what I'm sure will be the first of many noob-ish questions from yours truly... I'm studying as a mature student for a Computing Degree (encompassing web design, hardware, programming and systems analysis). The programming seems to be my weak spot this year. I enjoyed C++ last year, doing basic console applications, but progamming visually with VB in Visual Studio 2008 I'm struggling!
[Code].....
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Oct 16, 2009
Does 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).
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Oct 1, 2009
I'm looping all the properties in an object via reflection:
For Each p As PropertyInfo In values.[GetType]().GetProperties()
If p.CanRead Then
'Do stuff
End If
Next
how to determine whether the property in question is a generic List(Of T)? If it is I need to loop the list itself.
I've experimented with GetType and TypeOf but have not managed to get anything working.
To clarify, I want to keep this generic. I do not want to specify the type of T, I need to loop the list items and call the ToString method on each item. T could be one of a number of different types (application specific reference types). Is it possible to do this without specifying types?
(VB.NET 2005 with .Net 2.0)
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Nov 18, 2009
If I can generate a list of random integer with a click of the button and put the results in a list box using VB.Net but how do I randomly change several integer number generated by button 1 by clicking button 2? How I retain the results of button1 and change the results when clicking button2?I try before but the two button function code cannot relate to one another.
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Mar 23, 2011
Public Class notifierMain
Public Class Contacts
Inherits List(Of row)
Public Sub New()
[code]....
When I debug this winforms application I get curType = "notifier.notifierMain+Contacts+row" I want to the Validate function to know it is in MyContacts. How do I do this?
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Oct 27, 2009
In VS 2008, VB.Net, I am successful connecting to a local SQL Server and seeing all tables/views/procedures.I created an ODBC data source to a remote SQL server with a database of the same structure as the local one.The connection tests out ok. In the VS 2008 Server Explorer I add this source. When I click on the plus-signs to expand items, neither the tables nor the views show anything, whereas the full list of procedures appears.How can I see the lists of tables and views in Server Explorer for an ODBC source?
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Nov 5, 2011
I wish to make a project where a teacher views a list box with a list of students of a class. When he selects a name from the first list box the second listbox would change its data to show the grades for that one student.
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Apr 12, 2010
I have implemented inheritance for two parent classes called Table and Field. Each parent class has several child classes. In the Table parent class, I created a method that expects parameter List(Of Field).
I get an error when trying to pass in parameter List(Of ChildField) to the method that expects a parameter of List(Of Field). The error message is as below:
Value of type
'System.Collections.Generic.List(Of
com.hlb.icisbatch.data.ChildField)'
[Code]....
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Mar 16, 2011
This program is supposed to allow the user to check items in a checked list box. If the item is checked, it goes into the Completed List Box on the right. The program then adds the unchecked items to the Pending list box on the left. I keep getting placement values (e.g. O,1,2) instead of the strings (e.g. "Key Returned") in the list box results (see photo attached)
Public Class frmCheckOut
Dim i As Integer
Dim cleaning As String = "Cleaning Inspection"
Dim damage As String = "Damage Repaired"
[code].....
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May 16, 2011
Another program I am working on for fun, I am basically shuffling a list inside a listbox, what I want to do is delete the rest but not sure how to go through with that. At the moment I have this: [code] Just contains the code, declarations outside weren't included.So anyway, once clicked, it will call on the function to basically shuffle in a for loop, I was wondering if I should (or how should) create another function and call it in the click button or have just a loop in the click button so it deletes half the list. What I am doing is I have 20 list of items, I want the program to shuffle the items and then deleting the lower 10, meaning, if I had 10 items and wanted 5 top, I'd want: 0, 1, 2, 3, 4 and deleting 5, 6, 7, 8, 9.
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Aug 1, 2009
I currently have a list of words in a text file sorted in to alphabetical order and put into lower case, but I would like to be able to also display the line numbers on which these words are associated with.. but only one instance of.
For example,
"This is a random text
file that I
have just made
up this second"
[Code].....
As you can see above, I would like to show that "this" for example appears on line 1 and 4. Hopefully tabbed so that it keeps a nice look to it.
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Sep 21, 2010
I think (?) this is about object design, and perhaps about structural and/or creational patterns. But a bit hard to say when I only know a couple of patterns yet.[code]But... what if we INSTEAD want each Product instance only to (in some way) refer to one instance of a specific list of Components. So we wan't to save the products list to one file, and the components list to another file. Then would I build the objects the same way, or different? So let's then say we have now Class B as below. [code]
1. Will not need to update each component variable of the products list when the components list changes.
2. If the Product object shall be shown in a DataGridView, for editing properties, it seems easier to implement the selection of the component property.
Is this wrong approach? Is it suitable in some cases, and if so, when? Are there other solutions I perhaps am not aware of that would be appropriate? Is this about structural design patterns? and if so, can the alternatives above be catagorized to some pattern type? I don't really know exactly what I'm looking for.. But I think probably I'm looking to understand whether the object design will be determined by the way the objects are saved.. And if i shall save the objects by serializing to file, vs saving to a database, would I create the business objects differently?
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Jan 27, 2011
I'm getting System.NullReferenceException error when I try to add the employee info to the Employees list.
[Code]...
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