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 Replies
ADVERTISEMENT
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.
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
File I/O And Registry :: Binary File Primer - Read The Nth Record Without Reading The Whole File?
May 4, 2009I need to write data to a file, preferably in binary format, but I am unaccustomed with the concept. Where's the easiest place to get the basics? I could come here with a specific need, but I'm at the point right now where I am more willing to work within the confines of keeping it simple.
Here's what I know:
1. how to open a new file
2. how to specify the record length
3. how to close the file
Some specific questions:
Does the record length have to be constant throughout the file?
Can I read the nth record without reading the whole file?
File I/O And Registry :: Open / Read Binary File / Care To Check Code?
Jun 14, 2009I've gone through about 16 hours and two packs of cigarettes trying to figure this out. First a little background. I was using 6.0 up until 2004 when I went to prison. I'm out now, and trying to relearn the trade, using VS 2005. I'm currently porting some 6.0 code from another project, SpyCast Webcam Studio, into VB 8.0. It's disheartening, to say the least. None of the old built-in subs/functions work anymore, so I have to scour the forums to relearn each and every function.The section I'm doing now takes a snapshot from the webcam (Video API --> PictureBox --> Save as Jpeg), then upens the file to upload it to the server via HTTP POST. I've been using this code in SpyCast for years with no trouble, but I spent many hours trying to piece together the right code to open the binary file to read its contents. I pieced together two methods I found around the forums, one using FileStream() though the code I found wasn't for binary files, even though it said it was, so that code doesn't really work. Method two uses Microsoft.VisualBasic.FileOpen() and works better.
Here's the kicker. By the time I run through the rest of the rigamarole of uploading the file, by the time I read it on the webserver, it's *slightly* corrupted. It's a valid Jpeg, no errors, but the picture looks like when I use to watch the Playboy Channel when I was a kid scrambled with weird colors and whatnot. [code] Each "chunk" is basically one "line" of the file. It looks like a single LineInput() return is the text between two carriage returns. Am I correct? I tested this with a flat text file, and it looks true. However, That one input line returns the text or data with the carriage returns *stripped*! ***?!? =( Fine, I have no problem adding my own vbCrLf to each LineInput(), if I were opening text. but this's binary. A character could be Chr(10) or Chr(13), both of which are removed from the original file contents.So I could very well need to use something other than LineInput(), but I haven't found any other examples on the web using this method.
File I/O And Registry :: Implement A Routine To Read A Plain Text File?
Mar 21, 2010I need to implement a routine to read a plain text file, BUT that file has a predefined format.The file format is as follows:
Quote:
<FILE_PROPERTIES> 'The "< >" also appears
Propertie1="String" 'It's possible to have spaces after or before the "="
Propertie2="String"
Propertie3="String"
PropertieN="String"
[code]....
Is there any Windows API Routine to read something like that?Or could you point me an URL where something is implemented?I don't want a procedure to read the file line by line and comparing them with Line Input because blank spaces, empty lines and comments starting with " // " may appear too, and I don't want to take them into account, but also I need to save changes to the file, but only to the modified section, without having to read the whole file, and re-write it completely.
Binary access can't work, because I don't know what's the size of each "section", since the number of elements into it can change.
I need something like the "ReadINI" Windows API Procedure, but allowing me to read the "[XXX]" sections headers, and also the "<XXX>" file title header.
File I/O And Registry :: Load - Read - Locate & Copy Text In A File?
Aug 12, 2010Before I begin I would like to mention that I am not a noob in VB, it's just I've never had to do anything this complex before. Basically what I want is to have a program that you can load a txt file in, have it copy key words, and paste it in a textbox so I can use it later on. So in this text file, there is a bunch of info, but I am only needing a certain part. Here is an example of a text file (actually a .dat file, but is easily read):
[Code]...
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]...
File I/O And Registry :: File Read/write From A Collection?
Nov 17, 2010I am working on a program with multiple collections related to one another for a school project. Each collection needs to have its own defined properties and have the objects written (1 per line) to a text file.
I have all of that working.
When reading the comma-separated line from the file, I want to place one of the properties of the object in a listbox (so that all the objects' names will show up in the listbox). I think I have this part figured out...
My problem is that when you click on the name in the listbox, I would like multiple text boxes to be populated with the appropriate, corresponding properties of the particular object in the collection...is there a way for this to be done?
File I/O And Registry :: Read Metadata From Movie File?
May 29, 2009I want to read the meta data from a movie file and place the result in to a textbox.I've googled it and found no good samples for vb.net =( The data I'm interested in are the bitrate and the resolution and the extensions I'm interested in are .wmv, .avi and .flv the extension isn't known when the program loads because the movie is going to be inputted by the user..
View 1 RepliesFile I/O And Registry :: Can't Read / Write To Registry
Jan 21, 2012I have several programs that must write to HKLM in XP and Windows 7/64 Pro.The programs work in VB6 but not in VB.Net 2008 on target machines. It does works on our development machine. [code]I just cannot figure out why VB6 works but .net doesn't and fails only on the target machine not the development machine.
View 2 RepliesFile I/O And Registry :: Read A Text File?
Feb 5, 2009I have a coma seperated text file with loads of records. Usually when we read a text file we start from the first line and go towards the last. I know that there will be x comas per record.
But I want to start reading from the last line and then towards the top. This enables me to stop before I reach the top (depending on the data).
What would be the fastest way to read a text file in VB.NET. I am using VS2008. Basically I want to read from last line and stop when I want. I may not need to read the entire file.
File I/O And Registry :: Read File Like Notepad
Jan 31, 2009I need to read the following file in vb .net:"C:WindowsSoftwareDistributionDataStoreDataStore.edb". It contains info about installed software updates. I've taken a look at the file by opening it with notepad. This isn't a plain-text file obviously, but I can find and see the text I want easily with Notepad, and I want to extract this text by using VB .NET.
The problem is, i've tried to read the file by using an io.streamreader, but I can't get the same results as in notepad. I've tried to change encoding but that doesn't work. I mean in Notepad, I can read some text easily: "A s e c u r i t y i s s u e h a s b e e n i d e n t i f i e d" [...], but the only thing I get with the streamreader is some bunch of ugly characters, and the text I saw with Notepad isn't there.
Do I have to read the file in binary or what? HOW NOTEPAD DOES IT? HOW DO I READ THIS FILE LIKE NOTEPAD DOES?I absolutely need to extract some updates info that aren't in either the registry or WMI/QFE.
File I/O And Registry :: XML Read/Write
Apr 28, 2012I was unable to find anything in my searches for XML or INI on the forum so i apologize now if this has already been asked and answered before.
I have been searching Google for days now, trying to find information on Reading and Writing XML files. I wish to use them to replace INI files in my programs.
I have been using VB6 for years now, but was able to get a copy of VB.NET 2003 really cheap and so i am trying to learn how to do the things i did in VB6 in VB.NET 2003.
I was able to find code to write to an INI file, but was not able to successfully read from an INI file with any of the code i found.
I have been able to find code to write an XML file, but when i try to update it, it replaces the old file with a new one, and the old settings are missing, instead of the new settings added to it.
i can at least start migrating to VB.NET 2003, or if you read XML and update XML data, i can switch now. Here is the code i have for writing XML.[code...]
File I/O And Registry :: Read One Text File And Put Lines In Different Text Boxes?
May 12, 2009i have 5 textboxes in a form. I have a streamwriter that writes all of their text to on text file like this:
Code:
Dim xfile As String = Application.StartupPath & "/Set.txt"
If File.Exists(xfile) = True Then
Dim writex As StreamWriter = New StreamWriter(xfile)
[code]....
I was wondering how to get the text under the each number and place it in the corresponding textbox.
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 :: File System Object Does Not Allow Spaces In File Names
Feb 3, 2010I am working on a VB Console Application that takes an Autocad drawing type DWG and converts it to a PDF using a shell command that calls a third party application. In this case, acmecadconverter.exe from www.dwgtool.com. Then the PDF that is created needs a unique watermark, so I call a second application for that called pdftk.exe from www.accesspdf.com/pdftk/.
Everything works as intended, except when I try file names that contain spaces. The file system object does not tolerate spaces in the drawing file name. For instance, the following command gives me a system.io.filenotfoundexception...
My.Computer.FileSystem.RenameFile("Test Flowchart1.dwg", "Test~Flowchart1.dwg")
It's the same problem for all of my File System commands. Either file not found or invalid arguments.
The complete script I'm using is here:
Code:
Sub Main()
Dim arrArgs() As String = Command.Split(","), _
i As Integer, folderPath As String, myPart As String, _
[Code].....
File I/O And Registry :: Multidimensional Arrays - Save File/Load File?
May 13, 2012I'm currently developing an editor for an AFL management sim.I want to be able to load three or four multidimensional arrays to the program, then save them to the same file. I tried the tutorial on here but got completely muddled up. Why can't it be easy like in VB6 When it was like 10 lines of code tops!
View 5 RepliesFile I/O And Registry :: Random Access File Larger Than Text File?
Jan 7, 2009I am writing a program to calculate Pi to several hundred billion decimal places and this will require lots of GB of memory. I wrote a test program in VB2008 that saved the first 16 digits of Pi (without the decimal point) to both a text file and a random access file, just to be sure it was outputting the numbers properly. For reference the first 16 digits of Pi are:
View 8 RepliesFile I/O And Registry :: VB 2008 Express: Formatting A .txt File Written To A .txt File?
Jan 22, 2009I have a program that can save to a .txt file.The issue is I need it to be done in a tab delimited way.Basically:
TextHere<Tab>TextHere<Tab>TextHere<NextLine>
TextHere<Tab>TextHere<Tab>TextHere<NextLine>
I have this so far, but all it does is put the TextBox1.Text next to TextBox2.Text
Code:
SaveFileDialog1.Filter = "Text files (*.txt)|*.txt|All files (*.*)|*.*"
Dim FileWriter As StreamWriter
Dim results As DialogResult
[code]....
File I/O And Registry :: When Is File Ready For Using - Check Or The File Is Total Copied ?
Dec 6, 2010Our program will start with the help of a FileSystemWatcher object. How can we check or the file is total copied, for example the file is 100 Mbyte it take a time it's ready for use. Idea:
Do While True
Try
N = testForUse(BigFile)
If N = 1 Then Exit Do
[CODE]...
VS 2008 - .txt File - Write The File Path So That Someone Else Can Download My Program And File And Read The File
Feb 27, 2012Reading a .txt file in VB.net. My file path is C:UsersMyLilMulePepeDocumentsVisual Studio 2008Projectscurtain_calls.txt.
This is my line of Dim LoanOptionsFile As String = "C:UsersMyLilMulePepeDocumentsVisual Studio 2008Projectscurtain_calls.txt"
I can read the file when I run the program, but how do I write the file path so that someone else can download my program and file and read the file on their system?
File I/O And Registry :: Reading File Properties Without Loading File
Sep 19, 2010I want to be able to able to read the dimensions of a TIF image without loading the entire file.
PS Using Visual Basic 2008 on Vista64.
File I/O And Registry :: Read Char By Char From A String?
Dec 16, 2008i want to read a character 1 by 1 from a string and a .txt, i know all about stream reader so for the .txt would it be somthing like:textbox1.text = tr.readCharacter.i would prefer to be able to read from a textbox or String array though.
View 10 RepliesStreamreader - Text File - To Read Into A Listview - Read From A Specific Line In That File
Mar 11, 2010I have a txt file that I need to read into a listview, but I need to read from a specific line in that file. Below is a sample of the txt file to read,
6400,3200,2,95.5,84,76.6,0
1,2,-20,15,0,0,0,"NO",0,0
TOTAL GPM= 6400 HWT= 95.5 CWT= 84.0 IWBT= 76.6 ALTITUDE= 0
CODE]...
Read Binary File And In This File Found The String And Replace It With Other One And Save The File Afterwords?
Jan 11, 2011i need to read binary file and in this file found the string and replace it with other one and save the file afterwords. I found many example to read binary, but to find and replace is for me mistery.
View 3 RepliesFile I/O And Registry :: Error Is Coming Registry Access Is Not Allowed.While Opening A Key
Jan 21, 2009Error is coming Registry Access is not allowed.While Opening a Key.
Code:
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
NewDelete("HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun", "Sonia")
End Sub
[CODE]...
File I/O And Registry :: Writing (Default) And Dword(binary) Entries To Registry
Jan 31, 2009I've had a bit of a look around the net and on the forums but I've yet to find an answer to my question. I've got Visual Basic 2008 Express and I'm trying to write some registry entries, I can write strings fine just using
[Code]...
File I/O And Registry :: Safe A String Or Byte-array To File In Utf8 Format?
Sep 4, 2008trying to find a decent answer for my question; I do have a utf8 file which I (down)load, manipulate and wanting to save back again.The result always is that the file I produce is not in utf8 format;
Dim fs2 As New FileStream("c: est.dat", FileMode.Create, FileAccess.Write, FileShare.None)
Dim w As New BinaryWriter(fs2, Encoding.UTF8)
[code].....
File I/O And Registry :: Text File Tab Delimited Import Visual Studio 2010?
Nov 28, 2010trying to input a text file that's tab delimited that looks something like this.
2.2 5.6
3.7 9
1.2 9.1
[code].....