Dynamic Array Of Byte Arrays?
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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Apr 6, 2011
Objective: Combine byte arrays, read specific sections, and then cut byte array at specified point.
Private Sub DataArrival(ByRef aBot As xyzSocket, ByRef theData As Byte())
Dim RDLength As Int32
If aBot.ReceivedData Is Nothing Then[code]....
I'm not sure if I have this right to begin with because I can't test it without having it completed.
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Sep 20, 2011
I have 2 byte arrays. I want to merge these two byte array into 1 byte array.Usually, I just create a new byte array with length = byte array #1 + byte array #2. Then copy byte array #1 and #2 to the new byte array.do I have more efficient way to merge 2 byte array using VB.NET and .Net 4?
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Apr 7, 2010
Does this create a dynamic byte array?
Code:
Private m_renderedReport As Byte()()
Or this actually creates a structure?
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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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Mar 24, 2010
I am trying to Convert a data field stored as IMAGE ( SQL Server 2000) using Java to a byte array using VB.NET Java uses signed numbers for a Byte array where as VB dosent. Can somone point me to how I can covert java byte array to VB byte array?
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Jul 13, 2012
how to upload file using fileupload control into sql database. I have class where i created insert function and getting info frm the .aspx.vb file
Class File
========
Imports System
Imports System.Data
Imports System.Data.SqlClient
[coe]....
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Mar 30, 2009
I would like to create a function so that I can pass a string and it will return me the binary value, I will use this later in other parts of the script but I am getting an error that I don't understand.
Private Function ConvertToMD5(ByVal OldPassword As String) As Byte
Dim NewPassword As String = ""
'The string we wish to encrypt
[code]....
On the "Return hashedDataBytes I get "Value of type '1-dimensional array of Byte' cannot be converted to 'Byte'"
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Feb 26, 2012
I have 9 1-dimensional arrays of bytes and 1 of them is empty, I want to make the empty one equal to the others put together like you would a string:
Dim bla As String = "bla" & "bla" & "bla"
'now bla = "blablabla"
but instead:
[Code]......
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Sep 20, 2009
How do I read a raw byte array from any file, and write that byte array back into a new file?
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Nov 18, 2010
How could you convert a IntPrt to a Byte Array (Byte()) ?
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Jan 25, 2011
I have a byte array that I convert into a string like so Dim byt As Byte() = New Byte(255) {} s = New String(Encoding.ASCII.GetChars(byte))My question is when I look at the string in a debuger its clearly a normal string but when I compare it to what I know its supposed to be it doesnt equal. So i did a quick check and for some reason its return a string thats the length of 256 characters. So i did a s.trim and it still is 256 characters long.
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Oct 2, 2010
given my code below, I'm trying to figure out how to create an array of 1 byte containing 7 bits. So the byte in the array would contain 0111111 to correspond to mData_Out's boolean values. How would I change the following code? [Code]
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Aug 7, 2009
I'm trying to combine 2 byte arrays and then create a new byte array that contains the contents of both but running into a problem. The error says 'Source Array was not long enough.' I'm trying to combine HeaderByteArray and bytBuffer into newByteArray. I don't understand what Source Array is not long enough means and how to correct this.[code]...
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Mar 9, 2009
I am trying to compare two long bytearrays in vb.net and have run into a snag. Comparing two 50 meg files takes almost two mins so I'm clearly doing something wrong. I'm on an x64 machine with tons of memory so there are no issues there. Here is the code that I'm using at the moment and would like to change.[code]...
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Jun 8, 2011
I think there is Copy.to function but i cant find it
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Oct 6, 2008
I am in need of encrypting a byte array, but my encryption method that I found strictly deals with strings.
Here are the two pieces of code that I am dealing with.:
The byte array (the bytes that need to be sent encrypted)
Code:
Dim outStream As Byte() = System.Text.Encoding.ASCII.GetBytes(TextBox2.Text + "$")
serverStream.Write(outStream, 0, outStream.Length)
serverStream.Flush()
[Code]....
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May 16, 2012
am trying to pass a structure that contains 2D arrays as Byte from VB.net to a C++ dll. The dll returns the structure with the 1D arrays filled. I am using UnmanagedType.ByValArray to pass the arrays from VB.net to C++.
Sample :
----------------------------------------- Structure -------------------------------------------------------
<Serializable(), StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi, Pack:=1)> _
[Code].....
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Jun 11, 2010
I am having some major problems with byte arrays. First off the bigger array I have the more values go missing, I originally wanted to make a huge array and just dump like a 100mb chunk of memory in it but when I did that every byte in the array returned 0. So I experimented a bit and found 4kb to be the biggest chunk size to reliably not return 0.. ok I figured I'll just loop the 4kb and glue them back together later but no such luck, after being combined into the main array the bigger the number gets the more values that should be there just aren't.
Here's a code sample:
Dim retval(4095) As Byte
Dim combval(RLen) As Byte
For i = 0 To RLen - 4095 Step 4096
ReadProcessMemory(ProcAccess, i, retval, 4096, 0)
retval.CopyTo(combval, i)
Next i
WriteLine(combval(321603964))
WriteLine(ReadMemory(321603964, 1)(0))
So with the last 2 lines if I pull up some smaller number like 8 digits or so it reports back no problem but anything slightly bigger like the number i have written in there right now is just 0. After some additional research I discovered that the reason why 4kb is the max size I can reliably get is coz that's the size memory chunks are made of, "page" as they call it. Why the memory reading drops off at higher addresses alltho I suspect it has something to do with the way memory is structured and I am just not hitting the startpoint of a page anymore due to an offset or something somewhere.
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Jun 20, 2011
I am trying to get a count of all the times a byte sequences occurs in another byte sequences. It cannot however re-use a bytes if it already counted them. For example given the string let's assume the byte sequence was k.k it would then find only 3 occurrences rather than 5 because they would be broke down like: [k.k].[k.k].[k.k]. and not like [k.[k].[k].[k].[k].k] where they over lap and essentially just shift 2 to the right.
Ideally the idea is to get an idea how a compression dictionary or run time encoding might look. so the goal would be to get down to just 2 parts, as (k.k.k.) is the biggest and best symbol you can have.
Here is source so far:
[Code]...
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Jun 21, 2011
I have an aspx page which houses an iframe. When a button is clicked, a WCF is called to produce a PDF which is read into a byte array. I was storing the byte array in a Globals.vb file like this:
Public Shared PDF_Data as Byte()
The global was loaded from the parent aspx page like this:
PDF_Data = MyWCF.Create_PDF_File(SomeVariable)
After that, the iFrame's src was set to a blank aspx page, which had the following code in the page_load event:
'Write the PDF binary data to the screen (viewer)
Response.Clear()
Response.Buffer = True
Response.ContentType = "application/pdf"
Response.BinaryWrite(Globals.PDF_Data.ToArray)
However, realizing that this application will have several users who will get different PDF documents, I have learned that this is not the way to go. My shared variable would be accessible to all users, a big no-no.However, I am stumped as to how I'm going to store the byte array and make it available to a child aspx page from it's parent.
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Feb 10, 2011
The relevant code below is not achieving what I hoped it would. I intend for
1. SerialPortBufferTemp to be used as the container for each Serial Port Read.
2. _buffer should contain the resultant array from two separate Reads, the second appended directly after the first.
(E.g. 60 bytes read on the 2nd Read will be appended to the 168 bytes received on the first Read (228 total resultant byte length))
The problem with my code below is that _buffer has increase in size from 300 bytes to 600 bytes, skipped bytes 168 to 300 (leaving them all zeros) and added the remaining 60 bytes from the second read beginning at _buffer[300].
private List<byte> _buffer = new List<byte>();
byte[] SerialPortBufferTemp = new byte[300];
serialPort1.Read(SerialPortBufferTemp, 0, iBytesRead);
if (iValidRecordCtr == 0) {
_buffer.Clear();
[Code] .....
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Mar 31, 2011
Working with System.Cryptography, I'm noticing that data arrays up to a certain size will either conform to the size of the Initialization Vector (IV) or the size of the Key provided. So with a 48-byte Key and a 32-byte IV, up to around 42 bytes of data will encrypt to 32 bytes and 44+ will encrypt to 48 bytes of data. I've tested this with a variety of data arrays, and it seems to always come out the same... but I have a concern that higher byte values in the original array may result in longer encrypted arrays.
how or whether I can construct byte arrays that will be guaranteed to come out of Encryption at a pre-determined size?
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Dec 31, 2009
I can open a file in a hex editor and know that each 2 digits is a byte, they are 8 digits in binary correct?
How are they stored in arrays in VB.NET?
So if I have:
Dim xx() as byte =
What would I put after the equals? The hex digits from the hex editor? (This is just a program I'm not going to save, basically I don't want to open files to get etc. I want to put in the bytes in the 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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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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Nov 28, 2011
As a continuation of my other thread, "Finding A Pattern without a string Array (http:[url]....)", I would like to continue asking questions about enhancing a scanner with a few things:
1. Here is my code for finding signatures in a file:
'First the Signature Class:
Interface Signature
End Interface[code]......
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Jun 14, 2011
I didn't think it fair to post a comment on Fredrik Mörk's answer in this 2 year old post, so I thought I'd just ask it as a new question instead..NB: This is not a critiscm of the answer in any way, I'm simply trying to understand this all before delving into memory management / the marshal class.
In that answer, the function GetByteArray allocates memory to each object within the given array, within a loop.Would the GetByteArray function on the aforementioned post have benefited at all from allocating memory for the total size of the provided array:
Dim arrayBufferPtr = Marshal.AllocHGlobal(Marshal.SizeOf(<arrayElement>) * <array>.Count)
I just wonder if allocating the memory, as shown in the answer, causes any kind of fragmentation? Assuming there may be fragmentation, would there be much of an impact to be concerned with? Would allocating the memory in the way I've shown force you to call IntPtr.ToInt## to obtain pointer offsets from the overall allocation pointer, and therefore force you to check the underlying architecture to ensure the correct method is used*1 or is there a better way? (ToInt32/ToInt64 depending on x86/64?)
*1 I read elsewhere that calling the wrong IntPtr.ToInt## will cause overflow exceptions. What I mean by that statement is would I use:
Dim anOffsetPtr As New IntPtr(arrayBufferPtr.ToInt## + (loopIndex * <arrayElementSize>))
I've read through a few articles on the VB.Net Marshal class and memory allocation; listed below, but if you know fo any other good articles I'm all ears![URL]..
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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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