I am writing a program in VB.NET which loops through a file with some file paths in it to perform an action on. The file paths in this file are each on a line, and i'm looping through the file like:
Dim FileContents As String
FileContents = System.IO.File.ReadAllText("C:\File.txt")
Dim FileSplit As String()
FileSplit = FileContents.Split(vbCrLf)
For Each ThisLine In FileSplit
Dim FileModified As Date
FileModified = System.IO.File.GetLastWriteTime(ThisLine)
'Do something here
Next
Contents of File.txt is:
Y:\Users\localadmin\Desktop\MakeShadowCopy\FileInfo.vb
Y:\Users\localadmin\Desktop\MakeShadowCopy\FindFiles.vb
Y:\Users\localadmin\Desktop\MakeShadowCopy\MakeShadowCopy.sln
Y:\Users\localadmin\Desktop\MakeShadowCopy\MakeShadowCopy.v12.suo
The loop works fine, but it is throwing an exception on the line with GetLastWriteTime() on it, saying that the path contains illegal characters, but it is just a normal string with a file path in it.
If anyone has any ideas, or know how to escape the string going into GetLastWriteTime() that would be much appreciated :)
Thanks!
Probably the lines in your file are not correctly vbCrLf terminated.
If this is the case the Split cannot divide correctly your input in lines and you end up with the whole text passed to the GetLastWriteTime.
Instead of using ReadAllText you could use ReadAllLines and let the work to split the lines to the Framework that knows how to handle the file line break and carriage return codes.
For Each ThisLine In System.IO.File.ReadAllLines("C:\file.txt")
Dim FileModified As Date
FileModified = System.IO.File.GetLastWriteTime(ThisLine.Trim())
Next
Also add a Trim to the ThisLine variable to remove some unseen character added erroneusly to the line
Two ideas:
Use For instead of For Each and ensure that you're getting exception on the very first iteration. If not, you may have issues with one specific file path. Check out iteration variable value if that is the case.
Open the file in a hex editor and ensure that each line is terminating properly. You might have either CR (10) or LF(13) character at the end but not both as normal in Windows.
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 have a text file that I open and attempt to read the individual lines. I have used the same code before on other files with no problem, but for some reason, this particular file is strange. When I do the following command;
Line Input #1, read_string
the string read_string contains the entire sequence of each line in the file concatenated together. When I look at the special chararcters of the file I do see a cariage return. But just so you know what the file looks like, here are the first two lines (daniweb formatting is too strange to print text here),
k_arr[8'h1C]= {10'b001111_0100,10'b110000_1011} ;
k_arr[8'h1C]= {10'b001111_0100,10'b110000_1011} ;
Anybody know how I can read each line? apparently line input doesnt work for this file.
Try
Dim lines() As String
lines = Split(read_string, vbCr) 'splitting with Carriage Return delimiter
'did it work?
Debug.Print lines(1)
Debug.Print lines(2) Dim lines() As String
Each element of the lines array should now contain one line of your text file.
If it didn't work, try with another delimiter instead of vbCr, e.g. vbLf (line feed).
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
I'm trying to import a tab delimited file into a table.
The issue is, SOMETIMES, the file will include an awkward record that has two "null values" and causes my program to throw a "unexpected end of file".
For example, each record will have 20 fields. But the last record will have only two fields (two null values), and hence, unexpected EOF.
Currently I'm using a StreamReader.
I've tried counting the lines and telling bcp to stop reading before the "phantom nulls", but StreamReader gets an incorrect count of lines due to the "phantom nulls".
I've tried the following code to get rid of all bogus code (code borrowed off the net). But it just replaces the fields with empty spaces (I'd like the result of no line left behind).
Public Sub RemoveBlankRowsFromCVSFile2(ByVal filepath As String)
If filepath = DBNull.Value.ToString() Or filepath.Length = 0 Then Throw New ArgumentNullException("filepath")
If (File.Exists(filepath) = False) Then Throw New FileNotFoundException("Could not find CSV file.", filepath)
Dim tempFile As String = Path.GetTempFileName()
Using reader As New StreamReader(filepath)
Using writer As New StreamWriter(tempFile)
Dim line As String = Nothing
line = reader.ReadLine()
While Not line Is Nothing
If Not line.Equals(" ") Then writer.WriteLine(line)
line = reader.ReadLine()
End While
End Using
End Using
File.Delete(filepath)
File.Move(tempFile, filepath)
End Sub
I've tried using SSIS, but it encounters the EOF unexpected error.
What am I doing wrong?
If you read the entire file into a string variable (using reader.ReadToEnd()) do you get the whole thing? or are you just getting the data up to those phantom nulls?
Have you tried using the Reader.ReadBlock() function to try and read past the file length?
At our company we do hundreds of imports every week. If a file is not sent in the correct, agreed to format for our automated process, we return it to the sender. If the last line is wrong, the file should not be processed because it might be missing information or in some other way corrupt.
One way to avoid the error is to use ReadAllLines, then process the array of file lines instead of progressing through the file. This is also a lot more efficient than streamreader.
Dim fileLines() As String
fileLines = File.ReadAllLines("c:\tmp.csv")
...
for each line in filelines
If trim(line) <> "" Then writer.WriteLine(line)
next line
You can also use save the output lines in the same or a different string array and use File.WriteAllLines to write the file all at once.
You could try the built-in .Net object for reading tab-delimited files. It is Microsoft.VisualBasic.FileIO.TextFileParser.
This was solved using a bit array, checking one bit at a time for the suspect bit.
In VB.net I'm trying to read in a specific line from a file. An example of the line in the txt file is:
[PATH] = "/this/directory/run.exe"
Now I understand how to open the file for reading and writing in VB, but I need to parse out the path in the "" (quotation marks). Any help would be greatly appreciated!!
--Adam
Finding the line depends on what its distinguishing features are, but basically the idea would be to use LINQ. For example:
Dim line As String = File.ReadAllLines(path).FirstOrDefault(Function (s As String) s.StartsWith("[PATH]")
This gets you the first line that begins with "[PATH]". If you need better discrimination you could use a more sophisticated match such as a regex.
You can then extract the path from the line as per Rubens' or SLaks' answers.
Dim path As String = thatLine.Split("""")(1)
Assuming that the path will never contain quotes, you can use a regular expression:
Dim regex As New Regex(".+=\s*""(.+)""")
Dim path As String = regex.Match(line).Groups(1).Value
Alternatively, you can search for the quotes and extract the part between them using string functions, like this: (This assumes that there will always be exactly two quotes)
Dim pathStart As String = line.IndexOf(""""c) + 1
Dim path As String = line.Substring(pathStart, line.LastIndexOf(""""c) - pathStart)