I'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.
I 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
I have a function that returns a byte(), the only problem is that the array most times is to long and has 4 or 5 excess null bytes. I want to remove them and tried everything, but I cant seem to find anything that works.
View 3 RepliesI 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 RepliesOk 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 RepliesI 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"
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What 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.
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I know it may be quite easily for you. i have a text which contains 40 lines, I want to remove lines which starts with a constant text. check below data.
When I used (?mn)[+CMGL:].*($) it removes the whole text , when I use (?mn)[+CMGL:].*(
) , it only leaves the first line.
+CMGL: 0,1,,159
07910201956905F0440B910201532762F20008709021225282808
+CMGL: 1,1,,159
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I need to be able to strip the following prefixes from product codes as you see I have included a simple query while yes the below shows me the cm im not wanting i cant use replace as it code replace any instance of cm the prefixes are held in the supplire table cross refer with the products table
prefixes are not always two chrachters for example can be TOW
SELECT * , left(prod.productcode, LEN(sup.prefix)) AS MyTrimmedColumn
FROM MSLStore1_Products prod ,supplier sup
WHERE prod.suppid = 9039 AND prod.SgpID = 171
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I'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.
how to read bytes from a file... but is it possible to read each individual bit, one at a time?
View 1 RepliesIs it possible to change few bytes in a file to make unreadable or is it necessary to change each single byte?
View 1 RepliesI'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)
I'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"?
Probably missing something silly here, Her eis what my display looks like Sending image...(401303) I would prefer it displays as Sending image...(391 kb)
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I'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)
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How can i return the value? using bytes?
I 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 .
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I 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"
I 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?
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After 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)
I want to open a file and to replace from 2MB to 3MB of it with another 1MB file. Is it possible?
View 5 RepliesI am not so good with buffers and arrays and I dont know how to continue from here:
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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.
Well 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
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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
I 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.
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read 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 RepliesI 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 RepliesIs 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.
I'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:
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The question is quite simple for all of you . I have a binary file . A description for this file says that
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