Class With Dynamic Arrays Inside Another Class Which Also Has Dynamic Arrays?
Nov 15, 2011
Below you will find a code sample that I have dummied up to try and demonstrate the issue I am having. However, this is just a dummied up piece of code. The actual program has noting to do with STUDENTS or TEACHERS. Basically, the problem I'm having is trying to have a CLASS within another CLASS each of which contain ARRAYS that need to be dynamic in size. The sample has a CLASS called STUDENTS that can have in theory many students, the number of which are unknown to the CLASS. I need to be able to add STUDENTS to the ARRAY programmatically.
The CLASSROOM Class should also be an Array since each TEACHER will have MANY Students. There will be only 1 Teacher for a given classroom but the SCHOOL will have MANY CLASSROOMS. Again, I need to programmatically add Teachers and Students without having predefined Array sizes. The code I have listed below will NOT work but it demonstrates what I am trying to achieve. I want to be able to reference the CLASS by using something like this ...
School(iTeacherIndex).Student(iStudentIndex) = "Rick Smith"
I feel like I should be able to use ARRAYLIST in both classes but haven't been able to get it to work. I've tried DIM'ing as ARRAY and can't get that to work either.If I can get ARRAYLIST to work then I shouldn't need to worry about expanding the array via UBOUND (if it's even possible).The REAL question is "How do I have a CLASS within a CLASS, each of which has ARRAYS that need to be dynamic in nature so they can be expanded as needed? The size of the array cannot be determined ahead of time".
REMEMBER . . . the actual program has nothing to do with Students and Teachers. This was just my way of demonstrating the issue using an analogy that I thought everyone could understand. The actual Class is much more involved.I have purposely hardcoded some values just to make the sample easier to work with. This is NOT how I normally program but is just here to hopefully make things a little more clear.
Here is the sample code . . .
'***********************************************************************************
'***********************************************************************************
'***********************************************************************************
'Here is the code that is in the form - This obviously doesn't work
Private Sub TeacherTestDemo()
Dim iTeacherIndex As Byte
Dim iStudentIndex As Byte
[code]....
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Sep 25, 2010
I'm trying to create a dynamic jagged array. That is, one that i can increase the size of at runtime. Maybe its easier if I show you. I have a folder containing a varied number of files. What I want to do is set up a jagged array, with the file contents as the second array. So kind of like this:
Code:
FileList(0)
Filelist (0) (0) = Line1
Filelist (0) (1) = Line2
Filelist (0) (2) = Line3
[CODE]...
However, it throws a System.NullReferenceExeption when I try that. In addition, I don't understand jagged arrays all that well....Here is my code (that doesn't work). The jagged array must be accessible by other methods.
Code:
Imports System.IO
Public Class Form1
Public Skills()()
[CODE]...
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Jun 24, 2009
A project requires to allocate a varying number of byte arrays (buffers).
It would be ideal if the following definition would be possible:
Dim ArrayOfBuffers() as buffer(10000) as Byte
The byte arrays must be ordered sequentially because they have to be written to a file by efficient procedures destinationFile.Write(ArrayOfBuffer(3),1000,1000)
The number of buffers will change during program execution sometimes. Therefore it would be nice to be able to do a ReDim on the data structure when needed.
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Nov 17, 2011
Been trying to think out something for this one but i can't come up anything. Arrays is kinda tough for me.
I am trying to practice a program that:
1. ask the user for number of elements
2. Use IsNumeric Function to catch an error.
3. A 3rd form pops up showing random numbers like this:
0 45
1 23
2 56
3 75
4 34
5 99
Then, after i click a button called "Sort" It sorts the random numbers from lowest to the highest value.
Public Class Form1
Private Sub btnGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGenerate.Click
[Code].....
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Jun 10, 2009
I guess I'm the newbie. I've just started trying to learn Visual basic 2008 express edition. I'm an old cobol mainframer and I'm having a hard time understanding this language. My project is to read a log file looking for claim numbers and I need to check that each claim has a start record and an end record. I need to fill up a dynamic array because I don't know how many claims there will be. The array needs to hold a unique claim#, a start claim flag, an end claim flag.
[Code]...
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Feb 24, 2010
In the player vs computer tic tac toe game I've been working on there are 2 boolean arrays (one for the computer and one for the player) that track which cells have been taken. When all other moves have been exhausted I would like the computer to play a random cell. To do this I am trying to gather the indexes of all False values from the 2 arrays and add them to another dynamic integer array. The computer will then choose randomly from the new array. The two Boolean arrays are plyrTaken and cmptrTaken. The dynamic array is occupied.
Here I declared the arrays:
Public Class Form1
Private occupied() As Integer
Private plyrTaken(8) As Boolean
Private plyrPairs(14) As Boolean
Here I got the dynamic array ready for use:
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
ReDim occupied(0)
And here is the code I have attempted:
For index As Integer = 0 To 8
If plyrTaken(index) = False And cmptrTaken(index) = False Then
ReDim Preserve occupied(UBound(occupied) + 1)
[Code] .....
In the last block of code I was just trying to print the contents of the array to a list box so I could see if it was working. Obviously, it's not. When one position is occupied the list box shows the occupied cell index with a Zero. This really shouldn't be there as I want only taken cell indexes to be sent to array and list box. When a second position is occupied 7 zeros are added to the list box. Kinda shows promise as 9 total cells - 2 is 7 but there should be index numbers other than zero to represent the cells that have been occupied.
Also, the indexes shouldn't keep adding on to the dynamic array I need a way to clear the array and resize it back to 0. I tried adding
Redim occupied(0)
to the top of the code but that didn't seem to work.
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Oct 11, 2010
i am in the process of learning myself VB.net (2010 dotnet 4 )And am a litte confused in whats the best way to program what can be called an array.i want to have an array that looks like this,
{{"aap", 1}, {"noot", 2}, {"mies", 3, "boom"}, {"vuur", 4, 7}}
now i tried to declare
[code].....
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Apr 30, 2009
What should the set/get function look like for the following class?[code]...
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May 22, 2010
This section of code is part of a much larger program.However, I can't seem to find the problem with this error.Error: Object reference not set to an instance of an object.[code]I'm using this array inside of a class form to maintain the memory of a computer player in a rock, paper, scissors game. There are two computer players involved; thus, the need for a unique instance of each array for each player.I'm struggling with this program and all of my errors are gone until I try to run the main form.I can link more code if needed.
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Feb 14, 2009
I can't figure out why this does not work.
Public arrs(32) As ARR
Public Class ARR
Public nr As Integer
[Code].....
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Apr 8, 2010
Is it possible for one class to access an array of values within another class as a readonly property of the second class? All of the examples and references on class properties imply that one can only retrieve one value by calling a class' property.
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Aug 30, 2011
Ive currently got this:
Public Class World
Dim StringA() As String
Property SetString() As String()
Get
[code]....
I need StringA to be a Two-Dimensional Array. I've played around with it and was unable to figure it out..
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Feb 19, 2009
EDIT: SI have a web service which uses a class of functions in order to return data used in various business processes (via InfoPath). One of the functions takes a given SQLCommand object and executes it into a SQLDataReader. Now depending on the SQL command text used this may return one or many rows of one or many columns. So what is the best class for this function to return bearing in mind it needs to be serialized by the web service.
My existing code is:
Dim array As New ArrayList
Try
[code].....
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Apr 22, 2009
I need to have a dynamic URL preferably from a Test Classformatting this design pattern to handle dynamic links from tests. instead of a constant HomePageURL.
Namespace TestDesign
Public Class HomePage
Inherits IE
[code].....
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Oct 1, 2011
I am trying to use several Class arrays to hold values that I will cycle through at a later point to perform some calculations. I need to change the array sizes to fit the data as it is entered. I am using one procedure to set the first element of each array and then a separate procedure to pass the additional values as they are entered.
Until my last attempt at changing my code, my StartBalance sub seemed to work, I could step through and see the values assigned to the class arrays in the code block. However, when it moved on to the Transaction sub, it did not recognize that the first set of values were set, the array shows zero values for index 1.
I have gone through several changes trying different ideas from reading blogs and articles, but I guess I am not understanding how these work. I even used the class arrays directly instead of the Property procedures to see if I would get a different result, but I do not.
I believe I must be approaching this incorrectly and though I can find dozens of examples of setting class variables and even a couple on using arrays as class variable, I can not find any that show how to then pass values to those arrays.
Public Class Statement
Private _tranDate(1) As Date
Private _amount(1) As Double
[Code]....
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Feb 2, 2012
I am using vb.net by the way. From what I understand, Xna is not usable in visual Basic. Therefore, in order to create my characters, I defined a sprite class. Now my question is.... (I am drawing everything using a timer on the form btw by the process of invalidation.)... how do I use time to cycle through the images in an image array while the instance has no focus, and whilst the class inherits the "Control" class? Basically, how do i get these instances to act without user input? I want a character to eventually respond to user input, but I also need npcs that do not need any input in order to move themselves. Also, I need this in such a way that each instance's processes do NOT interfere with the processes of others. So that whatever timing I use does not also stall the whole window/form.
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Create a web browser with tabs and I want to add a "Open in a new Link" Button with a Custom Menu .
The problem is I'm trying to use a Dynamic Control(Webbrowser) created in a class from a local sub (A picture box) on the event click . But i get this error [code]....
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Jun 16, 2009
I've been programming in VB.net for a while off and on, but never really had a need to use custom classes till now.I built a function in a module to populate a class, The class how ever is supposed to refer to one instance.I need to create an array of this class but the amount of instances needed is not always known.Works fine till the class goes to populate the class array.[code]It's probably something simple, I've just starred at it to long. Keep gettitng "Object reference not set to an instance of an object."
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Dec 18, 2009
I have a For Each block loops through a list of objects, the objects are all instances of a single custom class I have made which has multiple properties.The logic used in this block uses a property of the custom class to do a set action, is it possible to dynamically supply which property it uses in the logic? This will be more efficient and prevent me from having to create this logic over for each property of the custom class.My best guess was that maybe it is possible with reflection, however my searches into reflection have left me more confused.
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Dec 26, 2011
I am using System.Collections.Generic List.I created new class[code]but i want "UserName" in "ONE" class property created dynamic.
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Feb 17, 2010
I have a vb.net class with properties defined as follows:
Private m_Property1 As String
Public Property Property1() As String
Get
[Code].....
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Dec 25, 2010
I have a small problem, classes and threading with classes. The problem I have is a dynamic array variable defined in class. In the code below, when error pauses the code, I can see the data in the correct form but I can't write rigth code that writes the data to richtextbox.
Public Class Form1
Public k() As Integer
Private Class zaratma
[CODE]....
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Aug 8, 2011
How can I create a class so that I'll just call it to my form:This is the code of my Add Text box button that adds multiple text boxes.
Public Class Form3
[Code]...
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Jul 15, 2010
I have created a user control which is inside a folder called Controls and the class is a partial class which inherits from Web.UI.UserControl. Now from my page which is one level up I just try to access the method inside the usercontrol and so trying to cast it as the type of user control.
But I get build errors. It just cannot recognize that class. I get Type not defined error. But at times it has recognized the class. Dont know why it does that.
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Apr 3, 2012
I have multiple user controls (the same one dynamically added to a form 4 times), and one class. I would like all of the user controls raise events in that one class. For example, if any of the user controls are clicked, I want it to send a string to the class to be processed and show a MsgBox "Control name was clicked"I am doing this as an exercise to reduce repeating the same code over and over directly in the control, and to avoid creating the class over and over to accompany each user control.
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Feb 3, 2010
I am new in this forum, also new in VB.Net I need to create a public class for insert and delete data to database Public Class My_DBFunctions
[Code]...
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May 9, 2010
In VB6 I load a recordset containg all of the records (6 fields per record)in a table into an XArray and then manipulate the records in the array and then write them back to the original table. The array issorted by the first field (1 to maybe 8000 or more) I need to find records in the array by an ID field and then move them (because of some external criteria that happens many times) from say number 400 to number 375. Then all of the other records between 375 and 399 were renumbered up 1 to fill the gaps left by the move.
The XArray worked well as it could find and also move to a next record easily to facilitate the revisions to each record quickly. Everything is done in VB6 in code and nothing visual needs to be shown to the user until say 2000 of these external changes are complete. What is the best, most efficient way to do this in the .Net framework in VB2010. Datasets, Dataviews. tableadapters, arrays. enums ?
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Dec 10, 2009
My assignment is to have a user enter in big integers using what i think is two parallel arrays. I got this far but now im stuck. I think i need to actually convert the text box input into an array but i do not know how to do that. I am all over the place in this project.
'Created/ Revised by: Jessica Falcetta
'Cap 204 Final Project: Big Integer Project
'Project Purpose: To calculate large integers through parallel arrays
[CODE]...
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Feb 2, 2010
I have a VB.net console app and I am opening a function in a dll written in fortran. I am passing 3 arrays through the function by reference. When they come back out the otherside they ahve all tunred to arrays of only one element And that element is 0.I read on the internet somewhere that when doing this kind of thing it is a good idea to only pass the first element of the array into the function.I tried changing my function declaration to accepting single elements rather than single dimensional arrays, and now the arrays are the same length before and after the function call, but they don't seem to be changing at all, so i'm not sure that this is working
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Oct 30, 2010
the statement Dim state(49) As String and maintain a list of certain states. The list of states should always be in alphabetical order and occupy consecutive elements of the array. The buttons in the program should give the user the following options: (a) Take the state specified by the user in a text box and insert it into its proper position in the array. If the state is already in the array, so report. (b) Take the state specified by the user in a text box and delete it from the array. If the state is not in the array, so report. (c) Display the states in the array. "
Private Sub states_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
state(0) = "Alabama"
[code]....
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