Is it possible for the following code to produce NUL values within a text file?
var temp_str = "123456;1234567"
My.Computer.FileSystem.WriteAllText(Path & "stats.txt", temp_str, False)
It seems simple, but it writes quite often and I'm seeing several files that get accessed by the application that have Strings written to as:
When opening the file with Notepad++. Some other editors show just squares, and it seems like each character is represented by a block/NUL.
So far I've been unable to reproduce this on my test system. I just find the files on a COMX module's file system that's been running in the field and comes back faulty, but I've been seeing enough of these files to make it a problem that needs to be solved.
Does anyone have an idea to prevent this behaviour?
Hard to say what the problem is without more code, but try this if you want to replace the existing contents of the file:
Dim fileContent = "My UTF-8 file contents"
Using writer As IO.StreamWriter = IO.File.CreateText(fullPathIncludingExtension)
writer.Write(fileContent)
End Using
Or this if you want to append UTF-8 text:
Dim newLines = "My UTF-8 content to append"
Using writer As IO.StreamWriter = IO.File.AppendAllText(fullPathIncludingExtension)
writer.Write(fileContent)
End Using
If you want to append Unicode text, you must use a different constructor for StreamWriter:
Using writer As IO.StreamWriter = New IO.StreamWriter("full/path/to/file.txt", True, Text.Encoding.Unicode)
writer.Write(MyContentToAppend)
End Using
Note that the True argument to the constructor specifies that you want to append text.
Related
Please help. I have a piece of code that's already working in other parks of my program, however fails to work when accessed by a certain form so i can't see there can be an error with it. Its an information storage project using text files. A screenshot of the exact code and the error:
I expected it to change the label text to the contents of the text file its trying to read.
Thanks everyone :)
Well, there must be one or more illegal characters coming from your "zoots1.txt" file!
Build the filename and see what it looks like:
Dim zoot1s As String
zoot1s = My.Computer.FileSystem.ReadAllText("zoot1s.txt")
Dim fileName As String
fileName = zoot1s + "c.txt"
MessageBox.Show(fileName)
Dim ClassStrain As String
ClassStrain = My.Computer.FileSystem.ReadAllText(fileName)
TempLabel3.Text = ClassStrain
Timer1.Start()
--- EDIT --
My bad. I Found the issue to be that there is a skip in text where it goes to a new line. As if i had added vbNewline to it. Is there any way to edit the text file and take away the last character so there isnt a new line.
Use the Trim() function to get rid of white space. Also use Path.Combine() to make sure the path is correctly separated from the filename with the correct number of backslashes:
zoot1s = My.Computer.FileSystem.ReadAllText("zoot1s.txt").Trim()
Dim fileName As String = System.IO.Path.Combine(zoot1s, "c.txt")
I think you just missed the most important thing, which is the whole specific path of your file that will be reading data from, specifically after the ReadAllText() method, so instead of this line:
zoom1s=My.computer.FileSystem.ReadAllText('zoot1s.txt")
You should edit it like this:
zoom1s=My.computer.FileSystem.ReadAllTex(My.Computer.FileSystem.CurrentDirectory & \zoot1s.txt")
I hope this can solve your problem.
^_^
I used over four different methods to get the text from a online text file: www.mysite.com/filedata.txt and overwrite it to another file.
Everything works, but I have only one problem. Everything is written in the first line and not the original format.
Example:
From:
Hello
Hi
Hi
To:
HelloHiHi
Here is just an example of a correct code which I'm using, but it doesn't work:
Using client As New WebClient()
client.DownloadFile("http://www.mystie.com/filedata.txt",
Application.StartupPath & "\file.txt")
End Using
The file is using a different line-break style that is not recognized by the edit control.
There are three different types of line-break styles that are in common usage: the Windows style (CR LF), the Unix style (LF), and the classic Mac style (CR).
Windows controls like the TextBox control naturally require the Windows style, CR LF. The corresponding escape characters for C# would be \r\n; on VB, you use ControlChars.CrLf or vbCrLf. On Unix, LF (\n, or ControlChars.Lf/vbLf) is more commonly encountered. If you are getting a file from an external source, like the Internet, it probably uses Unix-style line breaks, which aren't recognized as line breaks by the Windows TextBox control. The reason it works in what you call "advanced text editors" is that they support all these different styles of line-break characters.
This is exceedingly trivial to fix. Perform a character replacement on the string, replacing LF with CR+LF, before you display it in the TextBox.
' Download the file
Dim path As String = Application.StartupPath & "\file.txt"
Using client As New WebClient()
client.DownloadFile("http://www.mystie.com/filedata.txt", path))
End Using
' Read the file's text in as a string
Dim filedata As String = File.ReadAllText(path)
' Fix up the line endings
filedata = filedata.Replace(ControlChars.Lf, ControlChars.CrLf)
' Display the text in your TextBox
myTextBox.Text = filedata
I managed to solve everything by switching from textbox to richtextbox.
On a button click I have the following code to write what Is in my textboxes.
Dim file As System.IO.StreamWriter
file = My.Computer.FileSystem.OpenTextFileWriter("C:/Users/Nick/Documents/Dra.txt", False)
file.WriteLine(NameBasic)
file.WriteLine(LastBasic)
file.WriteLine(PhoneBasic)
file.WriteLine(NameEmer1)
On my form load, I load what is in the notepad from what was written, It is saying It is already being used(the file) which is true, how can I have two different functions(write, and read) manipulating the same file with out this error?
The process cannot access the file 'C:\Users\Nick\Documents\Dra.txt' because it is being used by another process.
And here is the code for my onformload
Dim read As System.IO.StreamReader
read = My.Computer.FileSystem.OpenTextFileReader("C:/Users/Nick/Documents/Dra.txt")
lblNameBasic.Text = read.ReadLine
I am sort of stuck on this problem, thank you
You need to close the file when you are done writing to it.
Dim file As System.IO.StreamWriter
file = My.Computer.FileSystem.OpenTextFileWriter("C:/Users/Nick/Documents/Dra.txt", False)
file.WriteLine(NameBasic)
file.WriteLine(LastBasic)
file.WriteLine(PhoneBasic)
file.WriteLine(NameEmer1)
file.Close()
To answer your question:
how can I have two different functions(write, and read) manipulating the same file with out this error?
If you really want to simultaneously read and write to the same file from two processes, you need to open the file with the FileShare.ReadWrite option. The My.Computer.FileSystem methods don't do that.¹
However, I suspect that you don't really wan't to do that. I suspect that you want to write and, after you are finished writing, you want to read. In that case, just closing the file after using it will suffice. The easiest way to do that is to use the Using statement:
Using file = My.Computer.FileSystem.OpenTextFileWriter(...)
file.WriteLine(...)
file.WriteLine(...)
...
End Using
This ensures that the file will be closed properly as soon as the Using block is left (either by normal execution or by an exception). In fact, it is good practice to wrap use of every object whose class implements IDisposable (such as StreamWriter) in a Using statement.
¹ According to the reference source, OpenTextFileWriter creates a New IO.StreamWriter(file, append, encoding), which in turn creates a new FileStream(..., FileShare.Read, ...).
I've been trying to use StreamReader to read a log file. I cannot verify what it is encoded in, as when I open it in notepad++ and select ANSI encoding, I get this result:
I'm getting the characters needed when using ANSI but they are followed by things like [NULL][EOT][SOH][NUL][SI]
When I try and read the file in VB (using StreamReader or ReadAll) with ANSI encoding selected the resulting string I get back is completely wrong.
How could I read a file like this in VB.net?
You could use the IO.File.ReadAllText("File Location", encoding as System.Text.Encoding) method,
Dim textFromFile as string = IO.File.ReadAllText("C:\Users\Jason\Desktop\login20130417.rdb", System.Text.Encoding.ASCII) 'Or Unicode, UFT32, UFT8, UFT7, BigEndianUnicode or default. Default is ANSI.
If you still don't get the text you need by using the default encoding (ANSI), then you can always try the other 6 different encoding methods.
Update...
It appears that your file is corrupt, using the code below I was able to get a binary representation of whatever is in the file, I got this,
1111111111111101000001110000010000000000000001010000000000010011000000000000100000000000000111100000000000100110000000000011100000000010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111111111111110100000111000001000000000000000101000000000001001100000000000010000000000000011110000000000010100000000000111111111111110100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000110011100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
The massive amount of null data would suggest that the file is corrupt, which would also explain why we are not getting a lot of data whenever we try to read the file.
The code,
Dim fileData As String = IO.File.ReadAllText("C:\Users\Jason\Desktop\login20130417.rdb")
Dim i As Integer = 0
Dim binaryData As String = ""
Dim ch As String = ""
Do Until i = fileData.Length
ch = fileData.Chars(i)
bin = bin & System.Convert.ToString(AscW(ch), 2).PadLeft(8, "0")
i = i + 1
Loop
As #Daniel A. White suggested in his comment, that file does not appear to be encoded like a "normal" text file. A StreamReader will not work in this situation. I would attempt to use a BinaryReader.
Rdb file? Never heard of it. Quick google makes it less clear - n64 database file, Darkbot, etc...
However considering the name you have, and the general look of the opened file, i would say its a binary file.
If you want to read the file in vb.net you'll need a library of sorts, and i can't help you with one until you are able to shed some light on what the file may be, or what it was created with.
I am using asp.Net MVC application to upload the excel data from its CSV form to database. While reading the csv file using the Stream Reader, if line contains lower case letter followed by Upper case, it splits in two line . EX.
Line :"1,This is nothing but the Example to explanationIt results wrong, testing example"
This line splits to :
Line 1: 1,This is nothing but the Example to explanation"
Line 2:""
Line 3:It results wrong, testing example
where as CSV file generates right as ""1,This is nothing but the Example to explanationIt results wrong, testing example"
code :
Dim csvFileReader As New StreamReader("my csv file Path")
While Not csvFileReader.EndOfStream()
Dim _line = csvFileReader.ReadLine()
End While
Why should this is happening ? how to resolve this.
When a cell in an excel spreadsheet contains multiple lines, and it is saved to a CSV file, excel separates the lines in the cell with a line-feed character (ASCII value 0x0A). Each row in the spreadsheet is separated with the typical carriage-return/line-feed pair (0x0D 0x0A). When you open the CSV file in notepad, it does not show the lone LF character at all, so it looks like it all runs together on one line. So, in the CSV file, even though notepad doesn't show it, it actually looks like this:
' 1,"This is nothing but the Example to explanation{LF}It results wrong",testing example{CR}{LF}
According to the MSDN documentation on the StreamReader.Readline method:
A line is defined as a sequence of characters followed by a line feed ("\n"), a carriage return ("\r"), or a carriage return immediately followed by a line feed ("\r\n").
Therefore, when you call ReadLine, it will stop reading at the end of the first line in a multi-line cell. To avoid this, you would need to use a different "read" method and then split on CR/LF pairs rather than on either individually.
However, this isn't the only issue you will run into with reading CSV files. For instance, you also need to properly handle the way quotation characters in a cell are escaped in CSV. In such cases, unless it's really necessary to implement it in your own way, it's better to use an existing library to read the file. In this case, Microsoft provides a class in the .NET framework that properly handles reading CSV files (including ones with multi-line cells). The name of the class is TextFieldParser and it's in the Microsoft.VisualBasic.FileIO namespace. Here's the link to a page in the MSDN that explains how to use it to read a CSV file:
http://msdn.microsoft.com/en-us/library/cakac7e6
Here's an example:
Using reader As New TextFieldParser("my csv file Path")
reader.TextFieldType = FieldType.Delimited
reader.SetDelimiters(",")
While Not reader.EndOfData
Try
Dim fields() as String = reader.ReadFields()
' Process fields in this row ...
Catch ex As MalformedLineException
' Handle exception ...
End Try
End While
End Using