.NET (Core and Framework)

21-Mar-18 23:11

Hi everybody

I want to delete lines in text file based on search criteria entered in textbox.

My text file is like this:

[account]
user = usertest
pwd = test
description = test
date = "21/03/2018"
address = "blah bla"
email = "yyyy'

[account]
user = usertest2
pwd = test2
description = test2
date = "21/03/2019"
address = "atatatta"
email = "ccccc'

when i enter in textbox (usertest) for deleting I want to delete all lines of this user.
I have tried something but I am not able to delete all lines

Dim sw2 As String = IO.File.ReadAllText(textpath)

Dim Lookfor As String = txtuser.Text.Trim()

If sw2.Contains(Lookfor) Then

sw2.remove

Please help

Gerry Schmitz22-Mar-18 6:00

Gerry Schmitz

22-Mar-18 6:00

1) Split string on "[account]"
2) Remove element containing "user = xxx" from split string collection
3) Rejoin remaining elements into a string; using "[account]" + newLine as a delimiter.

(Looks like an ".ini" type of file; you might find a ready made solution on Google for ".ini" files).

"(I) am amazed to see myself here rather than there ... now rather than then".
― Blaise Pascal

Andiko22-Mar-18 22:20

22-Mar-18 22:20

Thank you Gerry for the quick response

Please can you be more specific about my situation or could you give me a real example?

Thanks in advance

https://www.dotnetperls.com/split-vbnet

https://www.dotnetperls.com/convert-list-string-vbnet

https://www.dotnetperls.com/join-vbnet

Gerry Schmitz22-Mar-18 22:40

Gerry Schmitz

22-Mar-18 22:40

"(I) am amazed to see myself here rather than there ... now rather than then".
― Blaise Pascal

Andiko23-Mar-18 0:14

23-Mar-18 0:14

I can't create a list of string based on search criteria. If a search for "user= test" form textbox I want all the paragraph which belongs to this user to be included in list of string not just one row and then delete all rows which belongs to this user including [account], user,pwd,description,email,address,zip.

I think I don't need to split but join this in a string based in search criteria. (user= test)

Please help me with real code based on the list below

thanks

<b>[account]
user = test
pwd = test
description = test
email = "test@test.com"
address = "balalala"
zip = 235555</b>

Richard Deeming23-Mar-18 2:23

23-Mar-18 2:23

Try something like this:

VB.NET

Shared Iterator Function GroupAccounts(ByVal lines As IEnumerable(Of String)) As IEnumerable(Of IList(Of String))
    Dim currentAccount As List(Of String) = Nothing
    For Each line As String In lines
        If String.IsNullOrWhiteSpace(line) Then Continue For
        
        If String.Equals(line, "[account]", StringComparison.OrdinalIgnoreCase) Then
            If currentAccount IsNot Nothing Then Yield currentAccount
            currentAccount = New List(Of String)()
        End If
        
        If currentAccount IsNot Nothing Then
            currentAccount.Add(line)
        End If
    Next
    
    If currentAccount IsNot Nothing Then
        Yield currentAccount
    End If
End Function

Shared Iterator Function UngroupAccounts(ByVal groupedAccounts As IEnumerable(Of IEnumerable(Of String))) As IEnumerable(Of String)
    Dim started As Boolean = False
    For Each account As IEnumerable(Of String) In groupedAccounts
        If started Then
            Yield String.Empty
            Yield String.Empty
        End If
        
        For Each line As String In account
            Yield line
        Next
        
        started = True
    Next
End Function

Shared Function RemoveUser(ByVal groupedAccounts As IList(Of IList(Of String)), ByVal userToRemove As String) As Boolean
    Dim found As Boolean = False
    For index As Integer = groupedAccounts.Count - 1 To 0 Step -1
        If groupedAccounts(index).Any(Function (line) String.Equals(line, "user = " & userToRemove, StringComparison.OrdinalIgnoreCase)) Then
            groupedAccounts.RemoveAt(index)
            Found = true
        End If
    Next
    
    Return found
End Function

Usage:

VB.NET

Dim sourceLines As IEnumerable(Of String) = IO.File.ReadLines(textpath)
Dim groupedAccounts As IList(Of IList(Of String)) = GroupAccounts(sourceLines).ToList()
If RemoveUser(groupedAccounts, txtuser.Text.Trim()) Then
    Dim resultLines As IEnumerable(Of String) = UngroupAccounts(groupedAccounts)
    IO.File.WriteAllLines(textpath, resultLines)
End If

NB: This will remove any lines from the file which come before the first [account] header, remove any blank lines within an account, and ensure that all accounts are separated by two blank lines.

Now you need to review your password storage:
Secure Password Authentication Explained Simply[^]
Salted Password Hashing - Doing it Right[^]

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Andiko23-Mar-18 2:51

23-Mar-18 2:51

Thank you Richard

But it doesn't seem to work.

It doesn't throw any error.

I executes fine but the user account still remains in text file.

Any other help or way would be appreciated

Richard Deeming23-Mar-18 2:59

23-Mar-18 2:59

Then check the lines in the text file. You probably have a leading or trailing space, or extra spaces between "user", "=", and the username.

The line in the file needs to be exactly equal to:

user<space>=<space><trimmed username to delete>

For example:

user = usertest

If you have other characters on the line, it won't be found, and you'll need to change the search criteria.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Andiko23-Mar-18 4:13

23-Mar-18 4:13

in fact it has lot of space

The format is exactly like this:

[account]
user<space><space><space><space><space><space><space><space><space><space> = usertest
pwd<space><space><space><space><space><space><space><space><space><space> = test
description<space><space><space><space><space><space><space><space><space><space> = test
email<space><space><space><space><space><space><space><space><space><space> = "test@test.com"
address<space><space><space><space><space><space><space><space><space><space> = "blah blah"
zip<space><space><space><space><space><space><space><space><space><space> = 255555

there are nearly 27 spaces (27 time I pressed space) between user and "=" sign

How can i deal with it?

thanks

Andiko23-Mar-18 4:21

23-Mar-18 4:21

I have tried something like this

'Dim countMatchingLines As Integer = 0
'Dim lines() As String
'Dim outputlines As New List(Of String)
'Dim searchstring1 As String = txtuser.Text.Trim()
'lines = IO.File.ReadAllLines(textpath)
'For Each line As String In lines
' If line.Contains(searchstring1) Then

' countMatchingLines = 7
' End If

' If countMatchingLines = 0 Then
' outputlines.Add(line)

' FileClose(1)
'
' IO.File.WriteAllLines(txtpath, outputlines.ToArray)
' FileClose(1)

' Else
' countMatchingLines -= 1

' End If
'Next

but the program enters in indefined loop and is not responding

Richard Deeming23-Mar-18 4:22

Regular Expression Language - Quick Reference | Microsoft Docs[^]

23-Mar-18 4:22

Change the RemoveUser function to:

VB.NET

Shared Function RemoveUser(ByVal groupedAccounts As IList(Of IList(Of String)), ByVal userToRemove As String) As Boolean
    Dim found As Boolean = False
    Dim pattern As New Text.RegularExpressions.RegEx(
        "^\s*user\s*=\s*" & Text.RegularExpressions.Regex.Escape(userToRemove) & "\s*$", 
        Text.RegularExpressions.RegexOptions.IgnoreCase)
    
    For index As Integer = groupedAccounts.Count - 1 To 0 Step -1
        If groupedAccounts(index).Any(Function (line) pattern.IsMatch(line)) Then
            groupedAccounts.RemoveAt(index)
            Found = true
        End If
    Next
    
    Return found
End Function

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Andiko23-Mar-18 4:46

23-Mar-18 4:46

it throws an error:

System.InvalidCastException: 'Unable to cast object of type 'System.Collections.Generic.List`1[System.Collections.Generic.IList`1[System.String]]' to type 'System.Collections.Generic.IEnumerable`1[System.Collections.Generic.IEnumerable`1[System.String]]'.'

Thank you for your time

I am a beginner in vb.net Frown | :(

Richard Deeming23-Mar-18 4:58

23-Mar-18 4:58

Which version of Visual Studio are you using, and which version of .NET are you targeting?

The code I posted should work in .NET 4.0 or higher. If you're targeting an earlier version, you might need to change the parameter type on the UngroupAccounts function:

VB.NET

Shared Iterator Function UngroupAccounts(ByVal groupedAccounts As IEnumerable(Of IList(Of String))) As IEnumerable(Of String)

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Andiko23-Mar-18 5:11