I need download a CSV file and then read it. Here is my code:
tickerValue = "goog"
Dim strURL As String = "http://ichart.yahoo.com/table.csv?s=" & tickerValue
Dim strBuffer As String = RequestWebData(strURL)
Using streamReader = New StreamReader(strBuffer)
Using reader = New CsvReader(streamReader)
I keep getting this error: An unhandled exception of type 'System.ArgumentException' occurred in mscorlib.dll Additional information: Illegal characters in path.
What am I doing wrong?
Additional Info
In another part of my program I use this code and it works fine.
Address = http://www.nasdaq.com/screening/companies-by-industry.aspx?exchange=AMEX&render=download
Dim strBuffer As String = Historical_Stock_Prices.RequestWebData(Address)
Using streamReader = New StringReader(strBuffer)
Using reader = New CsvReader(streamReader)
Isn't my second code the same concept as my problem code?
you are giving it, essentially, a web url. somewhere in your code, it does not support the web url. it could be the streamreader. it could be the CsvReader.
what line of code does this point to?
the best bet is to save the file TO DISK, then read from disk.
UPDATE
here is an example to SAVE to disk:
using writer as new StreamWriter("C:\Test.csv")
writer.Write(strBuffer)
writer.Close()
end using
here is an example to READ from disk:
using strReader as new StreamReader("C:\Test.csv")
' this code is presumably how it works for reading into the CsvReader:
using reader as new CsvReader(strReader)
' now do your thing
end using
strReader.Close()
end using
Related
I have a CSV file in my project resources which I want to read using FileIO.TextFieldParser
I tried Dim parser = new TextFieldParser(My.Resources.ArticlesCSV), but since TextFieldParser expects either a path (as string) or a stream, this is not working.
I guess one possibility is to convert the resource to a stream, but I cannot find how to do that...
What is the best way to get this working?
You can create a new instance of IO.StringReader which is of type TextReader that TextFieldParser will accept. Just pass your CSV file (Thanks to AndrewMorton)
Using strReader As New IO.StringReader(My.Resources.ArticlesCSV)
Using textparser As New TextFieldParser(strReader)
textparser.Delimiters = {","}
While Not textparser.EndOfData
Dim curRow = textparser.ReadFields()
' Do stuff
End While
End Using
End Using
I am trying to copy the contents of an embedded file to a string in Visual Basic using Visual Studio 2013. I already have the resource (Settings.xml) imported and set as an embedded resource. Here is what I have:
Function GetFileContents(ByVal FileName As String) As String
Dim this As [Assembly]
Dim fileStream As IO.Stream
Dim streamReader As IO.StreamReader
Dim strContents As String
this = System.Reflection.Assembly.GetExecutingAssembly
fileStream = this.GetManifestResourceStream(FileName)
streamReader = New IO.StreamReader(fileStream)
strContents = streamReader.ReadToEnd
streamReader.Close()
Return strContents
End Function
When I try to save the contents to a string by using:
Dim contents As String = GetFileContents("Settings.xml")
I get the following error:
An unhandled exception of type 'System.ArgumentNullException' occurred in mscorlib.dll
Additional information: Value cannot be null.
Which occurs at line:
streamReader = New IO.StreamReader(fileStream)
Nothing else I've read has been very helpful, hoping someone here can tell me why I'm getting this. I'm not very good with embedded resources in vb.net.
First check fileStream that its not empty as it seems its contains nothing that's why you are getting a Null exception.
Instead of writing to file test it by using a msgBox to see it its not null.
fileStream is Nothing because no resources were specified during compilation, or because the resource is not visible to GetFileContents.
After fighting the thing for hours, I discovered I wasn't importing the resource correctly. I had to go to Project -> Properties -> Resources and add the resource from existing file there, rather than importing the file from the Solution Explorer. After adding the file correctly, I was able to write the contents to a string by simply using:
Dim myString As String = (My.Resources.Settings)
Ugh, it's always such a simple solution, not sure why I didn't try that first. Hopefully this helps someone else because I saw nothing about this anywhere else I looked.
For a long time I have been trying to debug why my parsing counts were off when downloading files to be parsed and been made to look really dumb about this. I did some debugging and found that the file I download when trying to decompress using GZipStream shows that it misses data from the original file. Here is my code for decompressing:
Using originalFileStream As FileStream = fileItem.OpenRead()
Dim currentFileName As String = fileItem.FullName
Dim newFileName = currentFileName.Remove(currentFileName.Length - fileItem.Extension.Length)
newFile = newFileName
Using decompressedFileStream As FileStream = File.Create(newFileName)
Using decompressionStream As GZipStream = New GZipStream(originalFileStream, CompressionMode.Decompress)
decompressionStream.CopyTo(decompressedFileStream)
Console.WriteLine("Decompressed: {0}", fileItem.Name)
decompressionStream.Close()
originalFileStream.Close()
End Using
End Using
End Using
Now what I do is return the newfile to the calling function and read the contents from there:
Dim responseData As String = inputFile.ReadToEnd
Now pasting the url in the browser and downloading from there and then opening using winrar I can see the data is not the same. Now this does not happen all the time as some files parse and decompress correctly. Each downloaded file has check counter to compare how many posts I am supposed to be parsing from it and that triggered me to see the mismatch in counts.
EDIT
Here is what I found in addition. If I read the problem file (as I said that only some files happen this way) by individual lines I will get all the data:
Dim rData As String = inputFile.ReadLine
If Not rData = "" Then
While Not inputFile.EndOfStream
rData = inputFile.ReadLine + vbNewLine + rData
End While
getIndividualPosts(rData)
End If
Now if I try to read an individual line from a file that is not problematic it will return nothing and so I will have to readtoEnd. Can anyone explain this odd behavior and is it related to the GZIPSTREAM or some error in my code.
Hey guys I'm trying to write to an existing file. here is my code:
Dim writeFile1 As StreamWriter = File.OpenWrite("H:\Visual Basic\LoginFixed\Accounts\" + frmLogin.txtUser.Text)
It's saying that Error "Value of type 'System.IO.FileStream' cannot be converted to 'System.IO.StreamWriter'. "
The exception indicates that the File.OpenWrite() method returns a FileStream object.
Dim writeFile1 As FileStream = File.OpenWrite("H:\Visual
Basic\LoginFixed\Accounts\" + frmLogin.txtUser.Text)
See the MSDN on File.OpenWrite() for more information.
I am making a class that is to help with saving some strings to a local text file (I want to append them to that file and not overwrite so that it is a log file). When I write with the streamwriter to find the end of the previous text, I get an error "the file is not available as it is being used by another process". I looked into this problem on MSDN and I got very little help. I tried to eliminate some variables so I removed the streamreader to check was that the problem and it was. When I tried to write to the file then it worked and I got no error so this made me come to the conclusion that the problem arose in the streamreader. But I could not figure out why?
Here is the code:
Public Sub SaveFile(ByVal Task As String, ByVal Difficulty As Integer, ByVal Time_Taken As String)
Dim SW As String = "C:/Program Files/Business Elements/Dashboard System Files/UserWorkEthic.txt"
Dim i As Integer
Dim aryText(3) As String
aryText(0) = Task
aryText(1) = Difficulty
aryText(2) = Time_Taken
Dim objWriter As System.IO.StreamWriter = New System.IO.StreamWriter(SW, True)
Dim reader As System.IO.StreamReader = New System.IO.StreamReader(SW, True)
reader.ReadToEnd()
reader.EndOfStream.ToString()
For i = 0 To 3
objWriter.WriteLine(aryText(reader.EndOfStream + i))
Next
reader.Close()
objWriter.Close()
End Sub
As Joel has commented on the previous answer it is possible to change the type of locking.
Otherwise building on what Neil has suggested, if to try to write to a file with a new reader it is difficult not to lose the information already within the file.
I would suggest you rename the original file to a temporary name, "UserWorkEthicTEMP.txt" for example. Create a new text file with the original name. Now; read a line, write a line, between the two files, before adding your new data onto the end. Finally Delete the temporary file and you will have the new file with the new details. If you have an error the temporary file will serve as a backup of the original. Some sample code below:
Change file names
Dim Line as string
line=Reader.readline
Do until Line=nothing
objwriter.writeline(line)
line=reader.readline
loop
add new values on the end and remove old file
You are trying to read and write to the same file and this is causing a lock contention. Either store the contents of the file into a variable and then write it back out including your new data to the file.
Psuedo
Reader.Open file
String content = Reader.ReadToEnd()
Reader.Close
Writer.Open file
Loop
Writer.Write newContent
Writer.Close