Writing Single Bytes To A BIN File?
Aug 20, 2011
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.
[Code]...
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Oct 27, 2011
We are using vb.net to write tiff images. After the image is first scanned into the system, we read it into bitmap memory, then we write it back out as a tif and pass in arguments that tell it what to put in the header. When we look at the original file, the header shows the "Subfile type" as "single page of multi-page image". But we noticed that after the file is written, the header now shows the "subfile type" as "Full-resolution image". We do not currently pass any argument in that tells it to do that.Is there a way to pass an argument into the function that writes the tiff file to tell it we want a single-page tiff and NOT a full resolution image? For some reason, our customer's tiff reader is not accurately reading some of these files and we believe it might be the cause of this.
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Sep 22, 2011
I've got my self in to a pickle here.I'm trying to do something I used to do in basic? At-least I think you can do this in Basic, you know Qbasic,What I'm trying to do is put 4-8 strings on to one line separated by a comma.Example might be:
writer.writeline (bob1, bob2, bob3, bob4) Out put might look like Test, Test2, Test3, Test4
I'm tried looking in to formatting of writeline/write, but I didn't get any where with it.
Also if this is possible- I would like to be able to read it just like :
reader.readline (Rbob1, Rbob2, Rbob3, Rbob4) If anyone cold just point me in the right direction, I'm sure I can figure it out - If not... Well I will ask another question.
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Jan 6, 2010
I have a single that might have a decimal place but might not. I have to put the digit before the decimal into the first 4 bytes and the digit after in the next 4 bytes.
So 1.1 would be 01-00-00-00-01-00-00-00
or 2.1 would be 02-00-00-00-01-00-00-00
or 1 would be 01-00-00-00-00-00-00-00
The digit before the decimal point is stored like an integer in bytes the same with the digit after the point. So 1.1 gets split into 1 and 1 and then stored as 2 DWORDS: 01000000 and 01000000
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Sep 7, 2009
I'm trying to read 5 bytes from a file and then do something according to what has been read. This is my code (I'll explain in a bit what's wrong):[code...]
It reads the 5 bytes I added to the encrypted file, but I want the CryptoStream to start from the sixth value and then copy the original bytes into the decrypted file, but it gives me an error:
Padding is invalid and cannot be removed.That's why I'm trying to make it read from the sixth value and then continue copying normally, but I'm stuck.
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Oct 12, 2010
I would like to use the USB port power as source and use the an amplifier on D+/D- Twisted Pair signal wires as my command line. I saw a thread suggesting to use the output as PWM. How can I send a single byte or stream of bytes to the port. Is it possible to read status of the D+/D- if they are shorted together?
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Feb 18, 2010
Since I like to use the ReadAllBytes and WriteAllBytes methods to save my variables to disk, I have had no troubles thus far with Integers.It has been easy to convert a short integer into a string of two bytes to save them using WriteAllBytes as following example:-
ReDimxji(0 To 601)
For I% = 0 To 300
J% = hbs(I%)
[code].....
But now I want to store some Single variables using WriteAllBytes, so I need to convert my single variables to a string of four bytes for each.
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Feb 16, 2011
How to check the Single byte character (e.g. English) and Double bytes character(e.g. Chinese) ?
Since I want to printing out their code which are representing in Hex.
However, Single byte character is using 2 digits of Hex. And Double bytes character is using 4 digits of Hex.
So, how can I check them and output with more readable pattern ?
input likes: 微軟 Microsoft output likes: B74C B36E 4D 69 63 72 6F 73 6F 66 74
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Sep 20, 2009
How can I get access in a fast way to the single bytes that form a double variable?
In pseudo-code I want to do something like this:
Dim myDouble as Double
Dim myArray(7) as Byte
myArray = myDouble
'continue doing things with the single bytes
The code is meant for use in a I/O-handler. The double-variables have to be sent / received via TCP. For this purpose they shall be put into / assembled from I/O-buffers.
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Jun 27, 2012
There are these 19 bytes (I am looking for combinations not the number of combinations)
17 00 00 00 A4 EA DB 13 02 00 00 00 00 00 00 A3 D3 02 CC
I need any possible unique combination which matches these "rules":
at least 4 bytes long the order of the bytes can't change(so 17 A3 D3 02 CC is ok but A3 D3 02 CC 17 isn't, because in the original string 17 was at the being but A3 D3 02 CC was at the end)
Let me try giving you examples of possible combinations:
17 00 00 00 A4 EA DB 13 02 00 00 00 00 00 00 A3 D3 02
17 00 00 00 A4 EA DB 13 02 00 00 00 00 00 00 A3 D3
17 00 00 00 A4 EA DB 13 02 00 00 00 00 00 00 A3
[Code]....
See the bytes stay in the same order for example the first byte 17 can only in the first byte's place
I don't want combination like
A4 17 02 CC
Because now 17 has changed order compared to A4
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Sep 22, 2011
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
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Sep 19, 2009
I am making the belated transition from VB6 to VB.NET (2008). I would appreciate some guidance on writing arrays to a file. I need to save and load large arrays of 4-byte floats (24 x 90,000 values is not uncommon). I can load or save them using nested for-next loops, but that's quite slow. I'd like to find a single operation that can read or write the binary data.In VB6 I could accomplish this (writing case shown) with Put #1 , , MyArray()I can read and write single variables from binary files without problems in .net. For example, [code]I have looked and looked, and Googled endlessly, but cannot find out how to accomplish a single-line numeric, floating-point array read or write in VB.NET.
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Nov 13, 2010
I 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.
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Sep 16, 2011
Ok 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.
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Feb 19, 2011
I 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]...
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Dec 28, 2010
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.
[code].....
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Jul 5, 2011
what is the different writing code application vbnet 2005 application for single user and multiuser?
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May 12, 2012
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.
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Aug 28, 2010
how to read bytes from a file... but is it possible to read each individual bit, one at a time?
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Oct 20, 2009
Is 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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Mar 26, 2010
I'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)
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Mar 17, 2010
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"?
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Aug 2, 2009
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)
[Code]...
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Jan 31, 2010
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.
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Dec 22, 2010
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)
[Code].....
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Jun 21, 2012
[Code]...
How can i return the value? using bytes?
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Mar 5, 2011
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 .
[Code]...
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Mar 13, 2011
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"
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Feb 25, 2009
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?
[Code]...
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Jan 2, 2010
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)
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