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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The 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 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.
Radio button 2 beacuse there are 3 and you have to pick one (The right one) to advance on to the next form.
View 4 RepliesI have a text file name list.txt which contains data like following;
AC-No. Name Time State New State Exception
100 ZULFIQUAR 09/04/2012 01:53 PM C/In Invalid
100 ZULFIQUAR 10/04/2012 01:39 PM C/In Invalid
100 ZULFIQUAR 11/04/2012 01:38 PM C/In Invalid
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how 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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I 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 RepliesIs there a method of using the stream reader to read webfiles?
View 1 RepliesFrom few days I am doing efforts to read web pages using webbrowser control in my desktop application. But it is very slower than my expectations(because I want to read lots of pages in minutes and browser control reads almost one page in 5 to 10 seconds), what I need is to read two or three tags written in web page.
So finally I decided to use something, which can give me only source code of page. I think StreamReader will help me to read it. I am not sure if it is flaxible with my purpose, or something else is there which can give me only html source code of web page.
I have written this code to read html code, but it gives error.
Quote:
System.ArgumentException: URI formats are not supported.
public static string Navigate(string URL)
{
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I'm using stream reader to read some text(txt format) n show in textbox1. I want stop at the second last line to get the string.Below is my code:
path="c:dic.txt"Dim reader As New StreamReader(path)Do While reader.?? //how to instruct to stop when read until second last line,because i don't know how many lines in the text file??
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.
Currently I am saving data from my applications by saving a text file via a stream reader as a string. I have come to a problem. In my current application, I have an array of the following structure:
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I've set up a stream reader to get data from a serial file, functionality for that is already set up.
My problem is that the program seems to be missing out every other line of code in the file, which kinda defeats the point of a serial file. [code]...
in an winForm app in VS2010 win 7 compiling to x86, I try to do what Alvas.Audio seems to work. See (c# ex: [URL] for reference.
Dim data() As Byte = wr.ReadData(second * i, second)
The result give me data.length()=0. I do not have any exception, I can read format from it and whatever reader I use I got this problem.EDIT : After some tests, it seems like the uncompressed file I create in the first step (in PCM format, with .wav extension) can not be recognized by the Alvas.audio library for the second step. I must miss something around Audio file markups or something alike.
Here is the code that might be the source (basically this is step 1):
Dim functOut As String = String.Empty
Dim wr As Alvas.Audio.IAudioReader = Nothing
Dim fs As IO.FileStream = Nothing
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How can I write the resulted stream to be sure I can read it again later?
I am downloading page data using the stream reader using readline.I want to concatenate each line into one long string for parsing The below line of code is not working: datajoined =dataline.Insert(datajoined.Length - 1, dataline.Length - 1)My inevitable goal here is to track stream data with a progress bar. But first I must learn to dload page data in chunks.
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I've got an application that reads a XML file via a stream reader. The problem is I can't edit my XML file and save it when others are using the application that is using the XML file at the time. how can i get around this?
View 1 RepliesIs there anyway to take a static stream reader, and switch it to another text file based on the user changing the file?
View 1 Repliesi 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 Repliesthis 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.
View 1 RepliesI'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 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 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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I have a dataGridView and tied it to a button that saves every time you click it. and every time you click it, I want to write a line to a txtfile that displays how many records were changed and the date that they were changed. Everything works fine but every time a save has been made it over write the previous entry on the text file. Here is some of the code.
If changes > 0 Then
MessageBox.Show(changes & " changed rows were stored in the database.") ' changes shows how many entries were changed
swDate.WriteLine(changes & " record changes on " & entryDate) 'entryDate is formated as date with value of "Now"
Else
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I am getting the right results in the text file except it over writes previous entry's so there is only one entry saved in the text file at any given time. I want it to keep building the text file so every time something is streamWrited the previous things in the text file stay there and it add to it. Looking at my problem I cant really justify or implement a For Each..Next or a Do While..Loop. My vb knowledge is limited so go easy on me.
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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What is the code to make a stream writer remove a certain line from a file stream?
View 1 RepliesI 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 have the first form and create 5 checkboxes which are connected to my db. Whichever checkbox is checked and the value will be inserted into the db (value: 1; data type: tinyint).And now, the second form will pull out the data base on the which checkbox is checked when the button is clicked. But for somehow i got stucked at the following code.
The first form:
Dim nValue As Boolean
If chkbox5.Checked = True Then
nValue = 1
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I am trying to use the eID SDK (for using the belgian ID-card) in VB. It's supported but I can't get it to work. I have never worked with sdk's before. I did manage to get it to work in c++ in console but I really need it in visual basic. Also the VB examples that come with the sdk are made in an older version of visual studio and when my version tries to convert them they don't work. I want to use the sdk to see when a card is inserted into the reader and to read out the data. (both i got to work in c++ console).
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