this project im working on is giving me a headache. am trying to write a program to recognie both ntfs and ext3 fileformats and enable the copying of files between them. ive done the ntfs bit and my problem is how do i implement the ext3 file system reader and writer using visual basic.net.any references would be really useful.
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i am working on a project that uses an magnatec card reader mse-750 iam facing a problem in making the machine on read mode so i can read from it iam using vb.net?
View 3 RepliesThe bigger problem is that I can't seem to get everything involving using stream writer and reader working. If I start of with a .txt file already correctly formatted then I can display it in the list box. But adding data during run time is not proving successful.
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I'm trying to setup a simple app that reads a file and then writes the contents to another file using OpenFileDialog and SaveFileDialog. Looking at the debbugger it looks like it's reading fine, I can see the data I want written. Towards the end of my code I get the following error message:"Illegal characters in path". I've researched this error. I'm not using any illegal characters such as /\? etc and the pathname contains all alpha characters. I'm pulling the test file from the C drive and trying to save it there as well.
Path: C:\Test.csv
My code:
Private Sub btnAppendData_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAppendData.Click
Dim Result As DialogResult
Dim FileContents As String
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I am trying to make my application read data from a file. Then save the data back. However I keep getting an error which says the file is still open so cannot be edited. I also read that there is an issue with the streamreader and streamwriter do not close the program straight away. I was wondering if anyone had a way around this or any alternative ideas. Heres my code so far!
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I am new to Visual Basics and I am using Visual Basic 2008 express. I have been using video tutorial on line to learn VB and they are great in explaining what is happening the code vs. just looking at code. I think from what little I can find I would be using StreamWriter WriteLine and StreamReader readLine .I am using a couple of forms. I am looking for simple basic code to use a form as a way of modifying timer intervals and store the values in a single text file on separate lines.
Description:
Form1: will contain the main code that will run. It will contain some timers. I want the timers to look in a text file for their intervals. Each timer would be on a different line.
Example:
Timer1 interval would be located on line 3
Timer2 interval would be located on line 6
Timer3 interval would be located on line 20
Form2: will contain 3 textboxes. This is where when I load form2 I will also read the same values from the text file to preload the text boxes. I will now be able to change the timer intervals as needed and press a button to update the text file. The update button will also reload the new timer settings on Form1. This is very similar to how a CNC Machine works with Parameter settings. This can be useful for storing many different settings for a form that a user can modify and be stored and reloaded next time the program runs.
I'm making a browser and for the favorites I'm using a reader and writer to read and write new favorite to a .txt file. Now if I edit the text file manually and load up the browser, the favorites show up as they should but the problem comes in when I add the a new favourite and then reload the application. Once reloaded the favorites seem to copy what was originally in the file and then whatever I added last at the bottom.
Here is the
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
WebBrowser1.Navigate(TextBox1.Text)
ListBox1.Items.Add(TextBox1.Text)
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I have a program that reads a text file tab delimted using OLEDb .I need to be able to allow the user to insert a user created record into the file which I can do.
The problem is I need to be able to let the user edit that record. From my understanding you can not edit or delete with OLEDB only insert So I thought I would read the file using stream reader, find the line I want to edit and just delete it, rewrite the file, then let the user insert a new record
If someone has a better way to perform this operation I am open its just the best way I could find with my limited knowledge and the reading and researching I have been doing thus far.
So I am trying to step-by step and first read the file which seems to work then find the line that would need to be deleted. So I was trying to use the
line.startswith method. I am using msgbox to see if that works before I continue but it doesnt seem to work I know my file has several lines starting with "Active" but my msgbox returns "False"
Here is the code I have so far
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We needed an inter-process reader/writer lock.We decided to use a file and lock the first byte using LockEx and UnlockEx. The class creates a file in the system temp folder when it is created. The file is created with readwrite access and share read|write|delete.We also specify DeleteOnClose so we don't leave loads of temp files laying around. Obviously AcquireReader and AcquireWriter call LockEx with appropriate flags and ReleaseLock calls UnlockEx.We have tested this class using a small application that you can run several instances of and it works perfectly. The application that uses it has a problem, which we have managed to re-produce in another small test app. In pseudo code it is
Create InterProcessReaderWriter
Dispose InterProcessReaderWriter without acquiring any locks
Launch a child process which takes a reader lock
The first time this runs, it works fine. If you attempt to run it again, while the child process from the first time is still holding the lock, we get an UnauthorisedAccessException when trying to open the file.This appears to be a permission issue, not a sharing violation but all the processes in this test case are running as the same user.
I have a smart card reader/writer hooked up to my serial port. i've already coded the program to give access to the serial port. How would I go about getting my Card Reader/writer recognized in my program. I basically want to click the "read button" and whatever is on the current smart card im trying to read, pop up on the screen.
View 1 RepliesI want to launch a application called Foxit Reader pdf Reader .I know System.Diagnostics.Process.Start(path) can do it but . Requirements are Foxit Reader should be installed on machine.Now if it is installed how to serarch for the path of its Executable to provide the parameter as I can not hardcode the path for different machines.
View 3 RepliesI have the code given below for reading and displaying all the drives on a computer.However,it does not read the NTFS mounted volume..I need the program just to read the mounted drive,
Module Module1
Sub Main()
For Each drive As String In System.Environment.GetLogicalDrives()
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I am trying to find some VB code examples on how to read the MFT/FAT Tables from NTFS and FAT32 drives. I am trying to scan the drive and to detect all deleted files and unallocated clusters on a particular drive.
View 4 RepliesI am having an issue with both Adobe Reader and FoxIt Reader when trying to print a PDF document. Both issues are different but a solution to either one will allow me to fix my issue.The issue I am having with Adobe Reader when trying to print using the following code is that it will not print it to the network printer I specify but just the default printer.
Dim AdobeReader As New Process
AdobeReader.StartInfo.CreateNoWindow = False
AdobeReader.StartInfo.Verb = "print"
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Assessing NTFS user folder permissions
View 4 RepliesI have a piece of code to debug. Because of unknown bugs it creates a dummy filename. I want to track all the pieces of code who fires that creates the dummy filename, so I can change the dummy file creation to a thrown exception. Since I the dummy filename is stored on a string, I plan to modify that string to contain an invalid NTFS filename, maybe containing invalid chars. Is there a reason to prefer some invalid chars over others? There are some predefined invalid NTFS filename destined to this purpose? (I may think of AUX , COM1 , LPT1 or PRN , but those names run the risk of start sending data to a port instead of throwing an exception).
View 1 RepliesI need to build an app that can create a network share and give it full read/write permissions to everyone.
I have this code to create/delete network shares: [Code] But it only changes the NTFS permissions, not the share permissions. I'm running Windows 7 RC (64-bit) using Visual Basic 2008 Express. Does anyone have any ideas on how to change the share permissions, not ntfs?
Basically, we have an application which batch creates a large amount of files (pairs of PNG plus ASCII). The file count can exceed the one million.The first time the application ran the results were quite disappointing. The files get stored in folder structures of maximum 2000 files per folder. The tree depth gets only to two levels (root + packs folders). So the results would be stored in folders like "pack1","pack2"..."packn" each containing no more than 2000 files (1000 pairs in essence).
So getting back to the results, what happened was that although the application reported over 1.4 million files written, the results were that files were missing from the filesystem and others were corrupt (PNG cant be read and ASCII were blank filled with spaces).The speed that the files were written was not anything great (about 7 files per sec) and the total size ranged from 160K to 1.5M (rarely). The PNG images are 2000x2000 in size although I doubt it has anything to do with my problem.
Everything is done in pure .NET (image and ascii generation).The OS that has been tried was Win 2000 Advanced Server, Win 2003 Server plus XP Pro. The hardware ranged from Dual Core Workstation to high spec servers. The irony is that on the XP system the number of corrupt files was quite low where on the other two all hell broke loose. There were event logs written stating Event ID 2021 on the Win 2000 system and Paging faults on XP, which lead me to the next approach.
We wrapped the code to do an Application.DoEvents every second and refresh various statistic UI components. We obviously added Stream.Flush().Plus we added code to check the files (re-read them) once they are written. Even added "WriteThrough" option to avoid the OS cache! The result was stuggering as no errors were report yet the NTFS table again got corrupted!Now we inserted Thread.Sleep(100) after writing and then reading to confirm the file. Obviously this is slowing down the process but hope to have more stable results.
Reading and article about Event ID 2021 we saw it was suggesting to modify registry values, but the IT dep did not wish to accept this as they believe it is an application error.In pseudo code, here is more or less what is done:
<try>
<Create Image in memory>
<Open stream to filesystem>
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I'm trying to make a small app that reads MFT from a NTFS drive and lists deleted files and their names. The code is not ordered since its not finished yet. I made it basing on information a read at ntfs.com and some other examples found on the net. But the problem itself is the following. I have hard disk with to NTFS partitions, the main one having 250 GB and the second one having 1,5 GB. If I execute my code on the smaller drive, (using D as parameter for readfile api), I get the list of all deleted files exactly (I checked it with a recovery file app).
The problem is when I execute it on the other drive (C where Windows is installed, 7 if it matters), the problem is that I cant find any deleted file!!. The code gets all the files from MFT and then saves in a string variable only the deleted ones, I found that after deleting one file, it also disappears from the MFT (at least using my code). So, there may be some other way in which NTFS marks deleted files? As you see in my code, I iterate through the MFT entries and, from those that start with FILE, I take bytes 22 and 23 (0 base) and evaluate, if its value is 0 then its deleted, otherwise, it isn't (its a file or directory I think).
Public Structure SECURITY_ATTRIBUTES
Dim nLength As Integer
Dim lpSecurityDescriptor As Integer
Dim bInheritHandle As Boolean
End Structure
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I need to gain access to Windows NTFS unique FileID...via VB.NET 2003...I found Kernel APIs ZwQueryDirectoryFile... calls which can return this info.
View 3 Replieshow would I accomplish saving a large piece of data, using the Stream Reader for the Line-by-Line, while keeping the carriage return line feeds in there?
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how do you open a text writter? (&keep it open)?
View 4 Replieshow do you open a text writer? (&keep it open)?
View 1 Repliesis it possible to print over a form instead of using a type writer (printing the text in a text box on the correct fields or blank lines)? my attempt i measure the x and y coordinates of the fields where the printer should print the text in centimeters by placing a scale on the form paper and taking the top left corner of the paper as the origin
i fed these x and y values measured with a scale to my vb .net program which:subtracts the height of the font from the y value (assuming the printer prints the topmost pixel of the character first)
and also converts the the centimeters to inches and multiplies them by 100 but when i print these fields over the form they are printed at wrong x and y coordinates for time being i adjusted the values (by trial and error) for 1 particular form but i dont want to do this for every form!!! what am i missing in my calculation that is making the printer print at wrong x and y coordinates?
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I'm using the stream writer to make a text file and write to it.I'm trying to get all the items from the listbox2 and save them to a text file called log.txt.The funny part is that its not giving me a ex.message.Do you see any error.[code]...
View 13 RepliesI am having problems getting my program to write to a txt file and also read the info in the file.The program does look for the file and throws an error if the file does not exist but it does not read or write the user info from/to the file. The program does everything else I need it to with this exception.[code]
View 3 Repliesmy company provides security card for certain seller agents that sold our products to customers. they need to claim their point or login through PDA application by scan barcode or swipe magstripe (magnetic stripe). i had written the code for barcode scanner, and i had written the code for magstripe reader, but it didn't need any comm control at all. all i had to do was focusing on textbox that showed data had read.i had device to write data, it is MSRE206 with serial port. now i need code in VB to write data to magstripe. i didn't have any experience with comm control in VB, so i didn't know where i have to start?how to write a program in VB so that i can write data to a magnetic stripe on cards?
View 9 Repliesi am creating a program which scans and saves images. in my program i have the option to save images and with each image i save it gets its own number for example: file1, file2, file3, file4 and so on. the only problem i have is getting the prgram to remember where it left off so it carry's on the number. my understanding is that i need to create some sort of stream writer or file stream class for this proccess to work. so it save's the last image number i was on, and carrys it on next time i open the program up again. and i also need it to re-write the new image number its on for next time. so i need to write and read the text file (.txt) and write it again if you catch my drift? i have a book to help but the wording in it is so confusing at the min, i m lost where to start.
View 1 RepliesI want to open a file with a stream writer. Delete it contains and write random data to it. And finally delete the file.
View 10 RepliesI am having a strange issue when using the StreamWriter where I am getting some strange charachers in my text file when reading data from a query string.
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