[RESOLVED] [2008] Change A Line In A Text File

[Louix]

One of the features of this app I am making requires that I do this.
XML is not used and CANNOT be used.
I need to find a line in a text file and remove it.
The file has a structure like this:

jjb:/dkfhs/fjds.udi
jjb:/dkfhs/sjsk.udi
jjb:/sjaok/susk.udi

Say I want to remove a specified line of the text file so the result would make the text file look like this:

jjb:/dkfhs/fjds.udi
jjb:/sjaok/susk.udi

How would I do it?

I searched the forums and found this but it does not remove my specified line.

 Dim lines As New List(Of String)



        'Read the entire file into a collection of lines.

        lines.AddRange(IO.File.ReadAllLines(Form1.Label7.Text))



        For i As Integer = 0 To lines.Count - 1

            If lines(i) = "jjb:/dkfhs/sjsk.udi" Then
                lines.Insert(i + 1, "")
            End If


        Next

        'Write out the new file contents.

        IO.File.WriteAllLines(Form1.Label7.Text + "seplugins\vsh.txt", lines.ToArray())

Please help, any of it is much appreciated
Louix.

[kleinma]

you can't "remove" a line from a textfile.

What you need to do, is read in the text file to a string, remove what you don't want from the string, and write the entire string back to the textfile.

This is what text editors do, you just don't see it happen behind the scenes.

That being said there are a few approaches to this method.

1) you could read in the textfile to a string, line by line, and omit the lines you don't want to read in WHILE you are reading in the original text file. Then simply write it back to the file.

2) read in the file in its entirety, remove the text you don't want, write the data back to the file.

[schaefer]

This is probably what you want

Dim lines As New List(Of String)
        Dim i As Integer


        'Read the entire file into a collection of lines.

        lines.AddRange(IO.File.ReadAllLines("C:\Temp\TestFile.txt"))



        While i < lines.Count - 1
            If lines(i) = "jjb:/dkfhs/sjsk.udi" Then

                lines.RemoveAt(i)

            End If
            i += 1

        End While
        
        'Write out the new file contents.

        IO.File.WriteAllLines("C:\Temp\TestFile.txt", lines.ToArray())

[Louix]

Wooo!
Thanks schaefer and kleinma the function works 100% now!
Louix.

[kleinma]

well there is really no need to loop like that if there is one specific line to remove from the file.

It can be done in just 4 lines of code:

        'GET ALL TEXT
        Dim myString As String = My.Computer.FileSystem.ReadAllText("filenamehere")
        'SPECIFY WHAT WE WANT TO FILTER OUT
        Dim replaceString As String = "jjb:/dkfhs/sjsk.udi" & Environment.NewLine 'NEED THE LINE RETURN AT THE END HERE OR WE WILL END UP WITH A BLANK LINE IN THE OUTPUT
        'REMOVE WHAT WE DON'T WANT
        myString = myString.Replace(replaceString, String.Empty)
        'WRITE DATA BACK TO FILE
        My.Computer.FileSystem.WriteAllText("filenamehere", myString, False)