Change Few Bytes In A File?
Oct 20, 2009Is it possible to change few bytes in a file to make unreadable or is it necessary to change each single byte?
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Read 2 Bytes Out Of 4 Bytes From A Text File?
Sep 22, 2011I created a text file contains 4 bytes of data
AABBCCDD
I just want to read the first 2 bytes (AABB) to execute it with my program.
Then I'll need to read the last 2 bytes (CCDD) for another computer routines
RijnDael Encryption/decryption - Select The Key Bytes And The Block Bytes From The Numeric Up/down?
Nov 13, 2010I want it to do is that you input a string, then you select an algorithm (Theres only going to be one RijnDael) then you input a key, then the Initialization Vector comes from "txtIV.text" then you select the key bytes and the block bytes from the numeric up/down, then you either encrypt or decrypt.
View 1 RepliesGeneric Restriction - Dont Select The Key Bytes And The Block Bytes From The Numeric Up/down?
Sep 16, 2011Ok i am having some issues designing a base-class to handle generics.Caveat is i need to restrict the type put in as a Numeric type, specifically Int16, Int32, or Int64 (Short or Long).I know you can do Of T as {Structure} but i dont want to select the key bytes and the block bytes from the numeric up/down.
View 2 RepliesBytes Written Exceed The Content-Length Bytes In XML Post?
Feb 19, 2011I keep getting a ProtocolViolationException "Bytes to be written to the stream exceed the Content-Length bytes size specified." on the following code.I've tried setting Content-Length numerous ways with no success.
Dim url = "https://domain.com"
Dim req As WebRequest = WebRequest.Create(url)
req.Method = "POST"
req.ContentType = "application/xml"
[Code]...
VS 2008 What Does This Line Exactly Do - I = Stream.Read(bytes, 0, Bytes.Length)
Dec 28, 2010What exactly does this line do?
i = stream.Read(bytes, 0, bytes.Length)
Does it read the entire message string sent by the client? I have a line to write to the stream later in the code and that does not seem to be sending anything back to the client, although the code around is excuting.
i = stream.Read(bytes, 0, bytes.Length)
While (i <> 0)
Try
' Translate data bytes to a ASCII string.
[code].....
File I/O And Registry - Modifying Bytes In File Without Rewrite
May 12, 2012I've been trying for a long time to create a sorted table of values in a particularly specific way, and I seem to be running into a wall in .NET's file operations. The premise is this - I'm creating a table of values which are being stored as [1 Byte][2 Bytes][3 Bytes]. The location within the file is a value that relates to these three stored values, and so I'm attempting to seek to a specific position in the file, write the 6 bytes into that position, and repeat. There are literally billions of these values, and the total file size is over 100 GB.
Now, I've tried multiple methods to do this, but every single time, it decides it needs to rewrite the ENTIRE FILE every time any change is made. This results in every one of these billions of iterations taking a good 15 minutes, making the task literally impossible. I'm using .NET 4, and I've attempted to use Text, Binary, and Random Access to get it not to rewrite the entire file every edit, but it simply will not obey.
So my question boils down to this: How do I edit specific bytes in a file without writing more than just those bytes? The entire file has been pre-created to the precise size required, and no bytes will be added or deleted in the process. I simply need to overwrite the bytes that already exist.
File I/O And Registry :: Read Bytes From A File?
Aug 28, 2010how to read bytes from a file... but is it possible to read each individual bit, one at a time?
View 1 RepliesEditing Bytes In A File?
Mar 26, 2010I'm trying to edit the bytes in a file. Using this code:
Dim stream As Stream = File.Open("file.exe", FileMode.Open)
stream.Write(File.ReadAllBytes("srcfl.exe"), "0446335", "srcfl.exe".Length)
Reading The First Bytes Of A File?
Mar 17, 2010I've got a web app where I'm trying to validate that an uploaded file is .PDF. I can't use ContentType because if the user renames the file to have a ".PDF" extension, the browser reports the MIME type to be ".PDF" even if it isn't.
I understand that one way to "validate" that a file is a PDF file is to look at the first four bytes, which should always be "%PDF". How do I open and read the first four bytes of a file in VB.NET to see whether or not they are equal to "%PDF"?
Search "2 Bytes" In The Application Process And Change It?
Apr 17, 2011How to search "2 bytes" in the application process and change it?For example, I want to change "2 bytes" the application, which is 32,000, but before that I need to search "2 bytes" numbered 32,000, and after I get a byte, I'll change it to 65535.
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
[code]....
Display KB Not Bytes 391 KB (401303 Bytes)
Aug 2, 2009Probably missing something silly here, Her eis what my display looks like Sending image...(401303) I would prefer it displays as Sending image...(391 kb)
[Code]...
Add And Remove Bytes On From Start Of A File?
Jan 31, 2010I'm trying to open an existent file save a bytes in the start of it to later read them.
How can I do that? Because the "&" operand isn't working fo this type of data.
I'm using Encoding.UTF8.GetBytes("text") to convert info to bytes and then add them.
Download Txt File Greater Than 100,000 Bytes
Dec 22, 2010I've been using the following code to download a text file from the web. It only downloads the first 100,000 bytes of the file which is no good if the file is big. The size of the file I'm downloading can vary from day to day, so I need to be able to download a text file of any size.
Dim wr As HttpWebRequest = CType(WebRequest.Create("http://sooty.postalgroup.co.uk/tempmac/nat-import.txt"), HttpWebRequest)
Dim ws As HttpWebResponse = CType(wr.GetResponse(), HttpWebResponse)
[Code].....
File Download - Return The Value Using Bytes?
Jun 21, 2012[Code]...
How can i return the value? using bytes?
Read 6 Bytes Floating From A File
Mar 5, 2011I have an old fashion Database with several random access files and I need to import the data to a new Sql Server dababase the data. There are tables with 6 Bytes floating numbers fields and we have no Number data type with that length in VB. I tried and tried and... and can't find. I found this code in the ERP folder, is AlphaBasic. It use an envoirement namend A-shell from Microsabio .
[Code]...
Replace Some Bytes In Binary File?
Mar 13, 2011I want to replace some bytes from a binary file .[code]...
If the value of the textbox is too short I want to replace the remaining bytes for a new value "0"
Streamwriter Creates File, But Is 0 Bytes?
Feb 25, 2009I am using the following code to write and empty (dummy) file to take up the remaining space on a device.RemSpace is a Public Variable declared as Long I have a function that gets the remaining space on the device and stores in the RemSpace variable (in bytes). I have tested with a msgbox to display the result of RemSpace, and it comes back correct (not 0). However, when the following code attempts to create the dummy file, the file is properly created but is only 0 bytes. What am I missing here?
[Code]...
Variables - Reading Bytes In A File?
Jan 2, 2010After getting the file name I create a new filestream and load all the bytes from the FileStream into a byte array, now I need to get certain bytes and store them in fields like the second 4 bytes are the time the file was created. When storing these in the variables should I store them as bytes or as string/integers/etc.
Or have I done it completely wrong?
EDIT:Should I be doing this way instead of a filestream?
Dim data() as Byte = File.ReadAllBytes(path1)
VS 2008 - How To Replace Bytes From File
Nov 13, 2009I want to open a file and to replace from 2MB to 3MB of it with another 1MB file. Is it possible?
View 5 RepliesVS 2008 Open File As Bytes
Oct 2, 2009I am not so good with buffers and arrays and I dont know how to continue from here:
[Code]...
My intention is to open an image file as bytes, Convert the bytes to a string, send bytes to server and server stores bytes in a database. Then I need to reverse the process and be able to convert the bytes to an image.
VS 2010 Recovering Bytes From A File?
Aug 1, 2011Well basicly i have a file from which i extract bytes and save them to a text file using this code :
Private Sub browse_Click(sender As System.Object, e As System.EventArgs) Handles browse.Click
Dim oFile As System.IO.FileInfo
[Code]....
Everything works well, but I don't know how to recover this file using the extracted data from bytes ! I Know for example the first byte of that file is 39 But i just can't do :
dim mybytes() as byte
mybytes(1)=39
You see what im talking about? I Want to recover those bytes from the same file I saved
Writing Single Bytes To A BIN File?
Aug 20, 2011I have a BIN file which I need to write a single byte to at the end and maintain the previous data. Here is an example.Viewed with a hex editor the file may have F0 FD 48 D3 C0 as the data. I want to be able to add to the end of it FF so that when I view it with the hex editor it is displayed as F0 FD 48 D3 C0 FF. I know how to open files for putting data but how can I take those characters and write them to the end of a file. I tried using the put function ( Put #FileNo, , MyStr) where MyStr = the characters in the textbox but it doesn't seem to work. Here is some code.
[Code]...
Adding A Chunk Of 256 Bytes In Decimal Value From A File?
Sep 29, 2011read each chunk of 256 bytes from a 32k file and then add the total value of each byte's decimal value. This will be some huge number which then needs to be converted to hex (Hex(number)and then truncate down to the LSB (I.E. 7F{4B}) and then convert the truncated byte (4B) back to a decimal (Num = Val("&H" & Num).
View 2 RepliesCannot Write More Then 1024 Bytes/Line To A CSV File?
Jul 1, 2011I am writing a CSV File from a Database. I am stuck in writing lines which become greater then 1024 bytes collectively. It write line terminator after 1024 bytes and thus adds the remaining string to new line which obviously results what I don't want. Is there any way so that I increase the line length limit to some reasonable amount of bytes?
View 16 RepliesConvert Image File Bytes Into RGB Values?
Oct 16, 2011Is there anyway to convert an image file bytes array into an array of the real RGB values of that image?
I don't really want to use GDI+ or the System.Drawing library, but simply apply a certain calculation/processing to every byte of the image file and get another array that contains the RGB values of every pixel in that image. I know it could be done as I know how to do it in a different programming language (Python) but not in Visual Basic.
Download File Size - Parsing Bytes?
Mar 29, 2011I'm trying to gather the size of a file to determine whether or not it's too large for my application to download.I currently have:
[code]...
First 2 Bytes In The Binary File The Number Of Records?
Jun 7, 2011The question is quite simple for all of you . I have a binary file . A description for this file says that
[Code]...
VS 2008 Write Bytes To File At Specified Position?
Nov 28, 2009I have 10 parts of a file. Each part is 10,000 bytes.Now say I receive these parts out of order meaning I cannot simply just write them in order as I receive them, but I am able to detect what part it is.
If I received part 3 how would I write those bytes in the 20,000-30,000 byte section of a file?
VS 2010 - Function - Search For Specified Bytes In Jpg File
Mar 4, 2012The code search for the specified bytes in jpg file and when first match is founded msgbox gives you position of the bytes in the file and Function stops. [Code] Now, because I am newbie to VB I have one question. How can I change the Function so that Function search the whole file for all byte matches?
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