Random Access Text File?
Apr 25, 2010
I'm doing a Program for a Friend of mine, He Want to have a Console Program Running on his Computer.OK the problem i am having is With Stream Read, I have 3 test users inside Test File, if User 1 logs in his information is store in logged file with time and data.but if User 3 logs on user 1 2 and 3 are all saved on the logged file
i dont have read to end of file in my Code.i dont have my Program with me, so i going off the top of my head i have something like this what i want to be able to find out how to do is Right from any part of the file and out put it, I take it i need to use Random Access but how to i code Random Access for this type of file. All i can find is how to Randomly place Words in a text file with Length and size.
[Code]...
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Jan 7, 2009
I 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:
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Jan 12, 2010
how to proceed. One of our customers is going to be sending me a flat file (ASCII-Text) that I have to break down and scan. Every line ends in a CrLf - So I know I can use StreamReader and ReadLine(). I did get it to work on one of the test files they sent.(A very Short file) However, the file is not delimited at all and every field is padded to the full length they specified. Here's the format of the file:
[Code]....
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Jul 14, 2011
When you need to do random access to the lines of a text file, the regular solution is to put those lines in a list and access them in that list.But doing this if the text file is large creates a large memory overhead and may cause some memory stress on the application.This class maps the file and provide the ability to read any particular line in the file at a random position, without the need to read or put in memory any other line but the desired line. The only memory overhead involve is the 1024 bytes buffer of the base stream.Even if the file mapping can be a process that consume a noticable amount of time if the file is very large ( ~ 5 seconds for each 100,000,000 caracteres) , once the mapping is done the access to a particular line becomes instantaneous regardless of the size of the file. (The file mapping can always be done at a convenient time (ex when the process load) and can be done on a worker thread The class is base on a StreamReader to support the differents Text Encodings Example uf usage ( As I say, if the file is very large, dont do it like that, but declare the class at a convenient time)
Imports Reader = System.IO.MyStreams
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[code]....
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Oct 19, 2011
Years ago when coding with VB6 and earlier, I used a file open command to create, read, and write a file that made it easy to store useful information.I believe it was binary and you wrote/read the data to a specific line in the file. When you opened the file with something like notepad, it just showed random ascii chars. When I needed a line of data, I could specify what line to load it from.
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Jul 1, 2010
I need an example of how to create and use a random access file
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May 20, 2010
Created Structure
opened file using FileOpen(1, "filename.dat", OpenMode.Random, , , bytes in structure)
used structure .ID = record number
FilePut(1, structure)
FileClose(1)
The program enters the first record but although when I enter more records it still shows only one record in the file.
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Jan 15, 2010
I am moving all of the prgrams that I have written, to VS2008. However, I use Random Access File Foemat for the databases that have been used for over a decade. I need to be able to read and write to a Random access file.I have multiple fields in the database and cannot lose access to this information.VS2008 doesn't use the following type of code to define the Fields that will be used in the Database. I did what it suggested, using the Structure / End Structure, but that was as close to a solution that I could find in the Help Files.
Type EquipType
EquipName As String * 32
Location As String * 28[code].......
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Jun 23, 2011
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
FileNum = FreeFile()
[Code].....
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Mar 2, 2010
I achieved reading and writing data to a random access file, buthow do I write and read data from a certain position in the *.txtfile? Would it be better if I created multiple file modes to
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Jan 30, 2010
I am using Visual Basic 2009 to create a file of records to store students tests scores.Currently i can write to the file, create new records etc. However i cannot edit a particular record, im sure i have to use file seek function but i have no idea where to start.here is some of my source code to give you an idea of where im at
Do While (Not EOF(1)) And found = False 'loop until no more records or the record is found
nosrecords = nosrecords + 1
FileGet(1, onestudent, nosrecords)[code].....
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Nov 2, 2009
how to read and write random access records in .NET. Now I know random access files are dead and the response on every query I found with google/bing/yahoo searches was don't use random access use Binary serialization but I can not. I have a situation where I need to read and modify 256 byte records in a file that is used by another application.
Now for a bit of background the file is made up of 27 fixed length records of 256 bytes. Each of the records has a separate structure consisting of 30-120 fields. The proplem I am having is I can create the record structures but when using the FileGet method I am receiving an error. Now I have found samples that showed the same format I am using that claim to work.
The error I am getting is Option Strict On disallows narrowing from type 'System.ValueType' to type 'ProgramName.ModuleName.Record' in copying the value of 'ByRef' paramater 'Value' back to the matching argument.
The basic layout (simplified) is as follows:
Code:
Structure Record
<VBFixedString(6)> Public SomeParam as String
Public SomeNumber as Short
[Code]....
Now the overloads for FileGet show all of the data types including Object. But I have tried various methods to retreive the 256 byte record but without success. Do I have to actually read each of the several hundred fields of the structure one by one? Or am i overlooking something (I have been known for this in the past)
Or (and I'll kick myself if this is the only way) do I just have to set option strict Off in the module and the code as above will actually work.
I would love to be able to just ditch the random access file but I have to keep it for compatibility with several other applications at this time.
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Sep 3, 2010
The application reads information similar to a DXF file. For purposes of discussion, the data consists of lines, those lines have endpoints, x1,y1,x2,y2. Within the file those lines create "paths", in other words, they are connected. There can be many separate paths within a single file. However in the original file, the geometry is not in any particular order, the paths are not indicated.
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Nov 17, 2010
I'm tasked with the job of creating a javascript version of a units conversion application written in vb6. I have the source code but I don't have vb 6. The source code uses a dat file to hold a conversion array (unit type, unit, xfactor, plusfactor). Getting the data out of this file would be good to me. I tried creating a little app in vb 2010 to write the data from that dat file to a txt file using essentially the same code as the source code. And that has been somewhat successful (took a while to figure out the fixed string business). Now I can pull the data out as an array. The math elements of this array look fine but the strings are somewhat read-able but too garbled to use. I can't seem to fix that by changing the character set/encoding.
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Apr 23, 2011
I have a label that reads a random line from a text file and that string becomes the text for the label.
Now the problem; the label will only work if it is clicked because the event handler is click.What I need is this to work automatically at startup. In other words, it should change the label's text to the random string of the text file on startup of the application.
Here is my code.[code..]
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Jun 9, 2012
How do you pick a random piece of text from a text file in this manner....
[Code]...
I need to pick a random answer, not including the question. let it be the simplest solution. I am only a beginner.
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Feb 24, 2010
This time, basically, i'm working with Random Access Files.I have this et of code to read data from a form a save it into a .dat file. This works fine.
Public Class frmDramaClub
Structure MemberRecord
Dim ID As Integer[code].....
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Dec 24, 2011
I have a flat file that is sorted by account number. I am migrating an application that was in vb6 to .Net. The application uses Random file access and uses a binary sort method to find a record.
Here is the code
Do While (low < high Or low = high) And (f = 0) 'Checking for an account match
middle = (low + high) / 2
FileGet(FileNum, Record, middle)
If Account < Trim(Mid(Record.Data, Byte1Start, Byte1Len)) Then
[Code] .....
From reading up on this in .Net it seems that using the Binary Reader seek method would be the alternative to using old vb6 random access code. The problem is the Binary Reader Seek method goes by Byte position instead of record number. How to convert my code to use a binary reader.
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Sep 21, 2011
I have a file that has names of competitors. I want to write a VB code that selects a random name from the file.What I need is show the names moving quickly once I press enter it will select the name.
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Jan 21, 2010
Im reading User/Pass from a text file. It has multiple user/passes in it and I want it to randomly select one to use. How would i do this? Here is the code im using now
Using parser2 As New TextFieldParser(filename2)
parser2.SetDelimiters(delimiter2)
While Not parser2.EndOfData
[Code].....
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Jan 8, 2010
I am using VB2010 and currently have a random letter and number applicaation but for some reason students dont seem to have the ability to type these in correctly!Does anyone have some code to put words from text file or string into a text box.
[Code]...
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Mar 16, 2010
I have a text document. i want to click a button and 10 random words out of the 196000 words shown in a textbox or listbox.
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Sep 3, 2011
I have a text file that includes a list of first names, each on their own separate line.
What I am trying to do is to find a way to click on my button and have my app open the list and randomly grab a name and place it into a textbox.
I would include some code but I'm not even sure where to begin.
I'm thinking that I will need to code the button to use the openfiledialog..create an algorithm to use a random copy line and return it into the textbox.
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Sep 3, 2011
I have a text file that includes a list of first names, each on their own separate line.What I am trying to do is to find a way to click on my button and have my app open the list and randomly grab a name and place it into a textbox.I would include some code but I'm not even sure where to begin.I'm thinking that I will need to code the button to use the openfiledialog..create an algorithm to use a random copy line and return it into the textbox.
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Jan 31, 2010
basically ive tried a few different methods which i have come accross by searching but none seem to work.
code so far after removing everything that didnt work is as follows
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
End Sub
End Class
im makng a spelling test type application so that each word is on a different line and that are displayed in a random sequency.
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Dec 5, 2009
getting a random line on a text file then assigning it to a variable?
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May 9, 2012
I basically have 1x text box and 1x button. I also have a text file set out as follows:
Fred Alston
Samuel Takahashi
Toni Tyree
Tonya Engel
[code]....
Except there are about 60 names.When the button is pressed, I want a name to be selected at random and placed into the text box.
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Apr 23, 2009
I'm working a program, which will download files from my server. But I need, program will download random files from text file on server, for example: I have [URL].
In links.txt are these links:
[URL] .....
If I run a program, it will download first link, after finish download it will download fifth link, second link etc. Downloading of one link works fine for me, but I need download more links...
Code:
theRequest = WebRequest.Create("[URL]")
So I need: theRequest = WebRequest.Create("RANDOM LINK")
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Nov 26, 2009
I got a little program that generates a random line of text from a .txt file and all is working well, at least for the most part.
On occasion I get an error message popup saying "Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: Index."
Here's my code:
CODE:
The last bit is where the random number is generated, which I am guessing where the problem itself is, but am unsure as to how to fix it...
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Jan 15, 2012
Im making a text based game that i need to randomly select different numbers of lines from a text file then pass them to a list box.[code]...
First the code needes to identify the 4th element then randomly select lines from lines that contain that element. The code needs to work out how many lines have a matching text to the 4th array then randomly select lines from that total no need for a maximum limit to that number.The same line must only been show the once at a time, but It can then be shown again on a different button click.[code]...
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