Delete line in TXT file but keep everything else - vb.net

Question

Hey all i am trying to figure out a way to delete something inside a text file but keep everything around it.
An example of this would be:
SDfmifgn349234024jn4tnge0b04tnEFGm34tmn34t0egonkerglnk
318erg4nergpERGhmboergn4t34tmg054
fg94t34tskmsdglnEGgjr894ERG94mrg34tSDFS$45352ty
GGreerkg0gm4m505556g0fdg6555fbd105f1g
And say i wanted to delete the 318erg4nergpERGhmboergn4t34tmg054 and therefore it would turn out to be saved as:
SDfmifgn349234024jn4tnge0b04tnEFGm34tmn34t0egonkerglnk
fg94t34tskmsdglnEGgjr894ERG94mrg34tSDFS$45352ty
GGreerkg0gm4m505556g0fdg6555fbd105f1g
But i am unable to find out how to go about doing that!
I've tried this code below that i found:
Dim dir As New DirectoryInfo(defaultNetworkDrive)
For Each file As FileInfo In dir.GetFiles()
If file.Extension = ".txt" Then
Dim ioFile As New StreamReader(defaultNetworkDrive & file.Name)
Dim ioLine As String ' Going to hold one line at a time
Dim ioLines As String ' Going to hold whole file
ioLine = ioFile.ReadLine
ioLines = ioLine
While Not ioLine = ""
ioLine = ioFile.ReadLine
ioLines = ioLines & vbCrLf & ioLine
End While
MsgBox(ioLines) 'SHOWS all the lines in the TXT file
If InStr(1, ioLines, encryptedText, vbTextCompare) <> 0 Then
MsgBox("True")
Else
MsgBox("False")
End If
'Dim sw As StreamWriter = file.CreateText("input.txt")
'sw.Write(ioLines)
'sw.Close()
ioFile.Close()
End If
Next
I do find it and its TRUE but i am not sure how to go about just deleting that line then saving it!
Any help would be great! :o)
David

Answer 1

You have to rewrite the file. Use StreamWriter to create a temporary file. Read one line at a time and write it to the output file. Skip the write if you don't want the line. Clean up by renaming the original, renaming the temporary then deleting the renamed original.
Use something better than a text file, like a dbase, if this is too slow.

Answer 2

You need to check for the string to exclude inside the loop where you read the lines:
While Not ioLine = ""
ioLine = ioFile.ReadLine
If ioLine <> "318erg4nergpERGhmboergn4t34tmg054" then
ioLines = ioLines & vbCrLf & ioLine
End
End While

Answer 3

If ioLines.StartsWith(encryptedText) Then
MsgBox("True")
Else
MsgBox("False")
End If
You are checking if the 'file' (ioLines) starts with the encrypted text, not the line (ioLine). I suspect that's why it isn't finding it.
I'm not sure if you are intending it, but I think adding the vbCrLf to ioLines will cause an empty line between each line. So your file output would be
LINE
[empty line]
LINE
[empty line]
...
To save the file without that line, you would need to write the lines you want to save to a new file.
Read line from file
If not excluded line
write line
Something like that (obviously off the top of my head) :)

Answer 4

Hmm, maybe I found the answer.
You are connecting all lines together:
ioLines = ioLines & vbCrLf & ioLine
Later you are trying to find the search string, but only at the start of the combined line!
ioLines.StartsWith(encryptedText)
This would only find the encryptedText if it be appear on the very first line of the file.
In your example the relevant string is somewhere in the middle of the iolines string.
So you should try to use
ioLines.Contains(encryptedText)
instead.
Edit:
You could try to do the following (just a though, I haven't tested it)
Dim fileLines as List(Of String)
fileLines = new List(Of String)(File.ReadAllLines(yourFileNameHere))
For i as Integer = fileLines.Count To 0 Step -1
If fileLines(i).Contains(encryptedText) Then
fileLines(i).RemoveAt(i)
End If
Next
File.WriteAllLines(yourFileNameHere, fileLines.ToArray)
HTH