Create A Dynamic Jagged Arrays
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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Nov 12, 2010
Im coming from a background of writing vba in excel, but have go to the point where im fed up of having everything running in excel and have started leaning vb.net. i am trying to do something i have done before, but am pretty much rewriting it as having got the end i now see a better way of doing things
Normally Google is full of help full answers but today it isn't, i may be i'm doing something odd or am trying to use completely the wrong tool for the job am happy to be told either.
I am trying to take data from a text file dumped from one of our databases, i have read the (huge) and oddly formatted text file in, converted it to a 1d array = InPutArray
[Code]...
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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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Jan 21, 2010
I have a question with jagged array, every element can contain strings, be empty or be nothing.
I would like to create a jagged array and put some strings into its cells.
Public Sub S1 ()
Dim MyArr(7)() As String ' OK
MyArr(1) = New String(8) {} ' OK the second cell contains 9 subcells
[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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May 28, 2011
How can I do the same as the following in VB.NET
List<T[]> result = new List<T[]>();
// single combination
if (k == 0)
{
result.Add(new T[0]); // T is function type argument of generic function How can I write the last line above in VB.NET?
I tried:
result.Add(New T(0)) 'doesn't work!
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Jan 16, 2012
So I have to create a jukebox with 3 different arrays, and 3 push buttons. Basically it looks like this:[URL]..
[Code]...
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Mar 14, 2011
In VB6 there is a feature called Control Arrays, where you name controls the same name and provide them an index value. This allows you to set a value by looping through the controls and setting each value. In VB .NET I can't create a control array?
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Jan 27, 2011
In VB.NET, I create my arrays like
Dim myArray = New ArrayList
But isn't there a way to create an array with elements without having to make a variable?
In Ruby, the long way was
array = Array.new
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Mar 4, 2011
my only objective is to create a scatter plot with only x and y axes. the data source should be from a 1 dimensional array. say i have these arrays:
[Code]...
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Feb 20, 2012
I have two arrays
a={a,b,c,d}
b={1,2,3,4}
now I want to create a 3rd array which should at least contains one numeric number and rest of alphabets, this code will generate unique usernames so it should not repeat the pattern of selection which is present in main array[code]...
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Oct 19, 2010
I currently have a sub that has a string builder that I'm wish to use as the content of a CSV which I will email later from a webpage. My stringbuilder is creating the content for the CSV but I don't know how to create the CSV dynamically (I don't want the CSV on disk).
Private Shared Sub BuildClientTrustBalanceCSV(ByVal sb As StringBuilder, ByVal clientsWithTrustBalance As List(Of NonPaymentHistory))
If clientsWithTrustBalance Is Nothing OrElse clientsWithTrustBalance.Count = 0 Then
[code]....
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Jan 1, 2011
Is there any way to create a multidinensional array that contains arrays of different lengths (similar to nesting arrays of different lengths in python).
Because if I were to declare a variable Dim accounts(2,2) As Integer all 1D arrays at each dimension have the same length. Is there any way to create an array so that this is not the case?
e.g The above code would create an array like this:
[[0,0],[0,0]]
but would it be possible to create this:
[[0,0],[0,0,0]]
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Mar 14, 2010
I am new to VB, trying to create a tic-tac-toe game but none of the tic-tac-toe tutorials use 2 dimensional arrays. Since tic-tac toe is 3x3 I created 9 buttons and want either an X or an O to appear depending on where the user clicks. I want one set of instructions to handle the multiple buttons. I was told to use Case statements.
This is what I have so far. Not sure how much is right but hopefully it gives you an idea of what I am looking for.
[Code]...
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Mar 17, 2010
I was wondering how you create a form with three lists. Each list representing a different array.
I guess the question is how do you take an array and make it into a list so it shows up on a list box?
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Nov 25, 2010
reading words from a text file and displaying them at random.The format of the text file is....
verb
noun
answer1
[code]......
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Jan 11, 2012
I have a form as Dashboards. I want to automatically refresh data without the data being read from the database and the user are shown.What is the best late for this scenario? I did this using a timer, but the best for this scenario is late?
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Jul 16, 2009
How to create a dynamic report?
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Dec 3, 2008
I need to create a label for every cell in excel that has a value depending on search criteria.Depending on what number is searched i need to display all cells in the row in different labels. There could be one label that needs to be created or many.Do i have to have each variable named differently or can i just use one label tag and give each label a different label.location = (x, y).
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Jun 3, 2012
I'm attempting to create a small app that allows a teacher to input 5 students with 5 test scores each. I need to create arrays of strings to hold the five students names, an array of five strings to hold each student�s letter grade, and five arrays of five single precision numbers to hold each students set of test scores.
[Code]...
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Jan 12, 2012
I was wondering if some of you can help me with a problem I can't seem to get around. I've got a database that contains a list of users who are connected to an application. The usernames and number of users connected will be random. What I need to do is to display two dynamic text boxes and also have a dynamic tooltip for each of the text boxes for each user displayed. If you look at the attached screenshot I drafted up, I'll only use the first user 'John' for this example.I will hardcode my example because getting the data from the database isn't the issue I'm having. My problem is figuring out how to make the text boxes and tooltips unique for each time someone visits the form. I would also like to be able to set the text within the boxes as well. So, I would need two textboxes for John called:
[Code]...
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May 26, 2009
I am attempting to create a long range calendar that dynamically loads (and unloads) event data as the user scrolls left or right through time. I'm really struggling to figure out how to lay the basic framework of the UI out and how to dynamically build the interface as the user scrolls by clicking and dragging the mouse in the view area. See the image below for a basic diagram of the intent. Each slice would have potentially multiple rectangles in it for events that occurred on that day (slice). I would like each slice to be a canvas to allow me to position those rectangles appropriately.
There are a few problems that I am not yet sure how to tackle but this is the first big one that I've been mulling over for a while and can't quite wrap my head around:
I know how to dynamically create controls but how would I go about adding things to one end of the scrollable content while removing things from the other depending on the way the user is scrolling?
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Mar 29, 2010
I have to ask my first question at some point, so here she goes.I am trying to create a dynamic list of objects. The objects will have several types (String, Integer) associated with them. Currently I am forming a Collection as I instantiate new objects.Is there a prefered to map this collection to, say, a Datagridview? Will I have to Iterate through the collection and add the rows at each iteration?Would I be better served using an ArrayList or something else over a Collection?
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Apr 7, 2011
I'm triying to create a dynamic query to Entity FW (i'm using Self tracking Entities over EF)
This is what i'm doing:
Public Class Specification(Of TEntity As Class)
Private _predicado As Expression(Of Func(Of TEntity, Boolean))
Public Sub New(ByVal columna As String, ByVal condicion As OperadoresComparacion, ByVal valor As Object)
[Code].....
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Jan 7, 2012
I am trying to create a dynamic string statement[code]...
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Jan 6, 2010
Currently I create a thread the following way (the normal way)
Public loginThread As Thread
Public loginThreadStart As New ThreadStart(AddressOf LogIntoWhatever)
Public callLoggedIn As New MethodInvoker(AddressOf loggedIn)
However, what I want to be able to do is something along the lines of (this obviously does not work, and is entirely pseudocode)
dim i as integer = 0
for i = 0 to i = 25
Public loginThread(i) as Thread
Public loginThreadStart(i) as New ThreadStart(AddressOf LogIntoWhatever)
next i
Public callLoggedIn as new MethodInvoker(AddressOf loggedIn)
Where I could change 25 to whatever I wanted and have that number of threads created. They would all be running an identical sub which does do not make calls of any kind to each other, they don't need knowledge of each other. Is anything like this possible?
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