Help!!
I have been set this task but i'm really unsure how to do this:
Sub Main()
Dim filePath As String = "C:\...\Projects\testing.txt"
Dim fileHolder As System.IO.StreamReader
Dim line As String
fileHolder = My.Computer.FileSystem.OpenTextFileReader(filePath)
line = fileHolder.ReadLine()
While line <> Nothing
Console.WriteLine(line)
Console.WriteLine("*****")
line = fileHolder.ReadLine()
End While
Console.ReadKey()
End Sub
"Edit the above program so that it only writes lines beginning with “The” to the console. You may find it helpful to revisit the lesson on String Handling to complete this task."
I have tried using if statements inside the while loop or a Do Until loop inside the While one, however this meant it would print the first line that contained "the" and not the third line that also contained "the", as the second line didn't.
Here is the (really bad code) that has failed me so far:
Dim filePath As String = "C:\...\Projects\testing.txt"
Dim fileHolder As System.IO.StreamReader
Dim line As String
fileHolder = My.Computer.FileSystem.OpenTextFileReader(filePath)
line = fileHolder.ReadLine()
Dim the As String = "the"
While line <> Nothing
If line.ToUpper.Contains(the.ToUpper) Then
Console.WriteLine(line)
Console.WriteLine("*****")
line = fileHolder.ReadLine()
End If
End While
Console.ReadKey()
Thank you for any help!!
Try this:
Dim filePath As String = "C:\...\Projects\testing.txt"
Dim fileHolder As System.IO.StreamReader
Dim line As String
fileHolder = My.Computer.FileSystem.OpenTextFileReader(filePath)
line = fileHolder.ReadLine()
Dim the As String = "the"
While line <> Nothing
If line.ToUpper.Contains(the.ToUpper) Then
Console.WriteLine(line)
Console.WriteLine("*****")
End If
line = fileHolder.ReadLine()
End While
Console.ReadKey()
Related
I'm trying to save a class to a text file and I'm getting mixed results. Half the time the last line of the add is in the file and sometimes not. I've not been able to get a consistent output to the file.
So, I added a debug to show me what was being written just prior to the StreamWriter.Write and it showed the line that I added but it doesn't show up in the file.
^ This line is the last line that isn't being written to the file.
Here's what my code where I save the data looks like:
Private sub SaveMemoUsersFile()
If _memoList is Nothing Then
return
End If
Dim memofile = Path.Combine(Configuration.DataFileLocations, $"{Configuration.CompanyID}ucMemoUsers.txt")
Const quote As String = """"
Const comma As String = ","
Dim both = $"{quote}{comma}{quote}"
Using sw = New StreamWriter(memofile)
For Each memoUsers As MemoUsers In _memoList
Dim sb = New StringBuilder()
sb.Append(quote)
sb.Append(memoUsers.Initials)
sb.Append(both)
sb.Append(memoUsers.EmailAddress)
sb.Append(both)
sb.Append(memoUsers.DelinquentLetterCode)
sb.Append(both)
sb.Append(memoUsers.Description)
sb.Append(quote)
'sb.Append(vbCr)
console.write(sb) <--- shows the last line
sw.WriteLine(sb.ToString()) <--- but doesn't write it to the file
Next
End Using
_memoList = nothing
End sub
Anyone have any suggestions? I'm completely lost as to why this is writing to the file randomly.
Might as well just build your file in the stringbuilder and write it:
Private sub SaveMemoUsersFile()
If _memoList is Nothing Then
return
End If
Dim q = """"
Dim b = $"{q},{q}"
Dim sb = New StringBuilder()
For Each memoUsers As MemoUsers In _memoList
sb.Append(q)
sb.Append(memoUsers.Initials).Append(b)
sb.Append(memoUsers.EmailAddress).Append(b)
sb.Append(memoUsers.DelinquentLetterCode).Append(b)
sb.Append(memoUsers.Description).AppendLine(q)
Next
Dim memofile = Path.Combine(Configuration.DataFileLocations, $"{Configuration.CompanyID}ucMemoUsers.txt")
IO.File.WriteAllText(memoFIle, sb.ToString())
_memoList = nothing
End sub
in my File Text I have the following things:
I have to make it start from somewhere and stop at a certain point.
but he only starts from that point, but he does not know how to stop at one point.
[Letters]
A
B
C
D
E
[Loop]
[Words]
Fish
Facebook
Google
Youtube
I should display Expected Output:
A
B
C
D
E
Then I should make it display
Fish
Facebook
Google
Youtube
but it shows me:
[Letters]
A
B
C
D
E
[Loop]
[Words]
Fish
Facebook
Google
Youtube
Code
Dim line As String
Using reader As StreamReader = New StreamReader(My.Application.Info.DirectoryPath & "\TestReader.txt")
line = reader.ReadLine
Dim sb As New StringBuilder
Do
Do
If reader.Peek < 0 Then 'Check that you haven't reached the end
Exit Do
End If
line = reader.ReadLine
If line.StartsWith("[Letters]") AndAlso line.EndsWith("[Loop]") Then 'Check if we have reached another check box.
Exit Do
End If
sb.AppendLine(line)
Loop
TextBox1.Text = sb.ToString
sb.Clear()
Loop Until reader.Peek < 0
End Using
This assumes that startPrefix and endPrefix will always be present in the file:
Dim startPrefix As String 'Set as required
Dim endPrefix As String 'Set as required
Dim lines As New List(Of String)
Using reader As New StreamReader("file path here")
Dim line As String
'Skip lines up to the first starting with the specified prefix.
Do
line = reader.ReadLine()
Loop Until line.StartsWith(startPrefix)
line = reader.ReadLine()
Do Until line.StartsWith(endPrefix)
lines.Add(line)
line = reader.ReadLine()
Loop
End Using
'Use lines here.
Are you really sure that you want to look for lines that start with those markers though? Wouldn't you really prefer to look for lines that are equal to those markers?
EDIT:
You could - and probably should - encapsulate that functionality in a method:
Private Function GetLinesBetween(filePath As String, startPrefix As String, endPrefix As String) As String()
Dim lines As New List(Of String)
Using reader As New StreamReader(filePath)
Dim line As String
'Skip lines up to the first starting with the specified prefix.
Do
line = reader.ReadLine()
Loop Until line.StartsWith(startPrefix)
line = reader.ReadLine()
'Take lines up to the first starting with the specified prefix.
Do Until line.StartsWith(endPrefix)
lines.Add(line)
line = reader.ReadLine()
Loop
End Using
Return lines.ToArray()
End Function
I got a .csv and I want to load it into a datagridview. I have a button called button1 and I got a datagridview called datagridview1. I click the button and it appears... including the header, which I don't want.
Please:
How do I exclude the header from the .csv ?
code:
Imports System.IO
Imports System.Text
Public Class CSV_Reader
Private Sub CSV_Reader_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim filename As String = "C:\Users\Gaius\Desktop\meepmoop.csv"
Dim thereader As New StreamReader(filename, Encoding.Default)
Dim colsexpected As Integer = 7
Dim sline As String = ""
DataGridView1.Rows.Clear()
Do
sline = thereader.ReadLine
If sline Is Nothing Then Exit Do
Dim words() As String = sline.Split(";")
DataGridView1.Rows.Add("")
If words.Length = colsexpected Then
For ix As Integer = 0 To 6
DataGridView1.Rows(DataGridView1.Rows.Count - 2).Cells(ix).Value = words(ix)
Next
Else
DataGridView1.Rows(DataGridView1.Rows.Count - 2).Cells(0).Value = "ERROR"
End If
Loop
thereader.Close()
End Sub
End Class
meepmoop.csv:
alpha;bravo;charlie;delta;echo;foxtrot;golf
1;meep;moop;meep;moop;meep;moop
2;moop;meep;moop;meep;moop;meep
3;meep;moop;meep;moop;meep;moop
4;moop;meep;moop;meep;moop;meep
5;meep;moop;meep;moop;meep;moop
6;moop;meep;moop;meep;moop;meep
7;meep;moop;meep;moop;meep;moop
8;moop;meep;moop;meep;moop;meep
9;meep;moop;meep;moop;meep;moop
10;moop;meep;moop;meep;moop;meep
edit:
[...]
Dim sline As String = ""
DataGridView1.Rows.Clear()
Dim line As String = thereader.ReadLine()
If line Is Nothing Then Return
Do
sline = thereader.ReadLine
[...]
The above addition to the code works but I have no idea why. Nor do I understand why I have to -2 rather than -1. I can't rely on guesswork, I'm expected to one day do this professionally. But I just can't wrap my head around it. Explanation welcome.
edit:
Do
sline = thereader.ReadLine
If sline Is Nothing Then Exit Do
Dim words() As String = sline.Split(";")
If words.Count = 7 Then
DataGridView1.Rows.Add(words(0), words(1), words(2), words(3), words(4), words(5), words(6))
Else
MsgBox("ERROR - There are " & words.Count & " columns in this row and there must be 7!")
End If
Loop
I've shortened the Loop on the advice of a coworker, taking his word on it being 'better this way'.
Another method, using Enumerable.Select() + .Skip()
As noted in Ondřej answer, there's a specific tool for these operations: TextFieldParser
But, if there are no special requirements and the string parsing is straightforward enough, it can be done with the standard tools, as shown in Tim Schmelter answer.
This method enumerates the string arrays returned by the Split() method, and groups them in a list that can be then used in different ways. As a raw text source (as in this case) or as a DataSource.
Dim FileName As String = "C:\Users\Gaius\Desktop\meepmoop.csv"
Dim Delimiter As Char = ";"c
Dim ColsExpected As Integer = 7
If Not File.Exists(FileName) Then Return
Dim Lines As String() = File.ReadAllLines(FileName, Encoding.Default)
Dim StringColumns As List(Of String()) =
Lines.Select(Function(line) Split(line, Delimiter, ColsExpected, CompareMethod.Text)).
Skip(1).ToList()
DataGridView1.Rows.Clear()
'If the DataGridView is empty, add a `[ColsExpected]` number of `Columns`:
DataGridView1.Columns.AddRange(Enumerable.Range(0, ColsExpected).
Select(Function(col) New DataGridViewTextBoxColumn()).ToArray())
StringColumns.Select(Function(row) DataGridView1.Rows.Add(row)).ToList()
If you instead want to include and use the Header because your DataGridView is empty (it has no predefined Columns), you could use the Header line in the .csv file to create the control's Columns:
'Include the header (no .Skip())
Dim StringColumns As List(Of String()) =
Lines.Select(Function(line) Split(line, Delimiter, ColsExpected, CompareMethod.Text)).ToList()
'Insert the columns with the .csv header columns description
DataGridView1.Columns.AddRange(Enumerable.Range(0, ColsExpected).
Select(Function(col, idx) New DataGridViewTextBoxColumn() With {
.HeaderText = StringColumns(0)(idx)
}).ToArray())
'Remove the header line...
StringColumns.RemoveAt(0)
StringColumns.Select(Function(row) DataGridView1.Rows.Add(row)).ToList()
You can skip the header by calling ReadLine twice. Also use the Using-statement:
Using thereader As New StreamReader(filename, Encoding.Default)
Dim colsexpected As Integer = 7
Dim sline As String = ""
Dim line As String = thereader.ReadLine() ' header
if line is Nothing Then Return
Do
sline = thereader.ReadLine()
If sline Is Nothing Then Exit Do
Dim words() As String = sline.Split(";"c)
' ... '
Loop
End Using
You should use VB.NET class that is designed and tested for this purpose. It is Microsoft.VisualBasic.FileIO.TextFieldParser and you can skip header by calling ReadFields() once before you start parsing in loop.
i'm trying to importe a csv file after creating on the same application, the only probleme is that even if a string matchs a line from the file, comparing them on vb.net dosn't give a true boolean i know i didn't make any mistakes because of the line with the commentary 'THIS LINE , i use a pretty small list to do my test and in that loop, there is always one element that matches exactly the string, but comparing them on vb.net dosn't return a true. the result of this is that just after saving the file to my computer while still having it on my listview1 on the application, i load it to the application again and it duplicates everything
Dim open As New OpenFileDialog
open.Filter = "CSV Files (*.csv*)|*.csv"
If open.ShowDialog = Windows.Forms.DialogResult.OK Then
Dim File As String = My.Computer.FileSystem.ReadAllText(open.FileName)
Dim lines() As String = File.Split(Environment.NewLine)
For i = 1 To (lines.Count - 1)
Dim line As String = lines(i)
Dim Columns() As String = line.Split(";")
Dim addLin As New ListViewItem(Columns)
Dim Alr As Boolean = False
Dim st as string=listView1.Items.Item(k).SubItems.Item(0).Text
For k = 0 To (ListView1.Items.Count - 1)
Dim st as string=listView1.Items.Item(k).SubItems.Item(0).Text
MsgBox(Columns(0)& Environment.NewLine & st) 'THIS LINE
If ListView1.Items.Item(k).SubItems.Item(0).Text = Columns(0) Then
Alr = True
MsgBox("true") 'never showsup even when the previous one show the match
End If
next
If Alr = False Then
MsgBox("false") 'the msgbox is only to check
ListView1.Items.Add(addLin)
End If
next
end if
I'm currently using the following to read the contents of all text files in a directory into an array
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
Within the text files are only 6 lines that all follow the same format and will read something like
forecolour=black
I'm trying to then search for the word "forecolour" and retrieve the information after the "=" sign (black) so i can then populate the below code
AllDetail(numfiles).uPath = ' this needs to be the above result
I've only posted parts of the code but if it helps i can post the rest. I just need a little guidance if possible
Thanks
This is the full code
Dim numfiles As Integer
ReDim AllDetail(0 To 0)
numfiles = 0
lb1.Items.Clear()
Dim lynxin As New IO.DirectoryInfo(zMailbox)
lb1.Items.Clear()
For Each txtfi In lynxin.GetFiles("*.txt")
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
ReDim Preserve AllDetail(0 To numfiles)
AllDetail(numfiles).uPath = 'Needs to be populated
AllDetail(numfiles).uName = 'Needs to be populated
AllDetail(numfiles).uCode = 'Needs to be populated
AllDetail(numfiles).uOps = 'Needs to be populated
lb1.Items.Add(IO.Path.GetFileNameWithoutExtension(txtfi.Name))
numfiles = numfiles + 1
Next
End Sub
AllDetail(numfiles).uPath = Would be the actual file path
AllDetail(numfiles).uName = Would be the detail after “unitname=”
AllDetail(numfiles).uCode = Would be the detail after “unitcode=”
AllDetail(numfiles).uOps = Would be the detail after “operation=”
Within the text files that are being read there will be the following lines
Unitname=
Unitcode=
Operation=
Requirements=
Dateplanned=
For the purpose of this array I just need the unitname, unitcode & operation. Going forward I will need the dateplanned as when this is working I want to try and work out how to only display the information if the dateplanned matches the date from a datepicker. Hope that helps and any guidance or tips are gratefully received
If your file is not very big you could simply
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
For each line in allLines
Dim parts = line.Split("="c)
if parts.Length = 2 andalso parts(0) = "unitname" Then
AllDetails(numFiles).uName = parts(1)
Exit For
End If
Next
If you are absolutely sure of the format of your input file, you could also use Linq to remove the explict for each
Dim line = allLines.Where(Function(x) (x.StartsWith("unitname"))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uName = line.Split("="c)(1)
End If
EDIT
Looking at the last details added to your question I think you could rewrite your code in this way, but still a critical piece of info is missing.
What kind of object is supposed to be stored in the array AllDetails?
I suppose you have a class named FileDetail as this
Public class FileDetail
Public Dim uName As String
Public Dim uCode As String
Public Dim uCode As String
End Class
....
numfiles = 0
lb1.Items.Clear()
Dim lynxin As New IO.DirectoryInfo(zMailbox)
' Get the FileInfo array here and dimension the array for the size required
Dim allfiles = lynxin.GetFiles("*.txt")
' The array should contains elements of a class that have the appropriate properties
Dim AllDetails(allfiles.Count) as FileDetail
lb1.Items.Clear()
For Each txtfi In allfiles)
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
AllDetails(numFiles) = new FileDetail()
AllDetails(numFiles).uPath = txtfi.FullName
Dim line = allLines.Where(Function(x) (x.StartsWith("unitname="))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uName = line.Split("="c)(1)
End If
line = allLines.Where(Function(x) (x.StartsWith("unitcode="))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uName = line.Split("="c)(1)
End If
line = allLines.Where(Function(x) (x.StartsWith("operation="))).SingleOrDefault()
if line IsNot Nothing then
AllDetails(numFiles).uOps = line.Split("="c)(1)
End If
lb1.Items.Add(IO.Path.GetFileNameWithoutExtension(txtfi.Name))
numfiles = numfiles + 1
Next
Keep in mind that this code could be really simplified if you start using a List(Of FileDetails)