Question

I’m making an application in Visual Basic 2010 that will allow me to easily create .dev web addresses for my XAMPP local hosted sites.

So far, I’ve managed to add to the necessary files, but not remove.

I need a way to remove all text between two markers in a txt file. For example:

120.0.0.1    localhost
120.0.0.1    alsolocalhost

##testsite.dev#start#
127.0.0.1    testsite.dev
##testsite.dev#stop#

##indevsite.dev#start#
127.0.0.1    indevsite.dev
##indevsite.dev#stop#

I want to remove all the text between the ##testsite.dev#start# and ##testsite.dev#stop# markers, as well as removing the markers themselves.

In my visual basic code this is what I have so far:

Sub removeText(ByVal siteName)
    Dim fileName As String = "hosts.txt"
    Dim startMark As String = "##" + siteName + "#start#"
    Dim stopMark As String = "##" + siteName + "#stop#"

    'Code for removing text...

End Sub

All I need now is to be able to remove the text I want, without touching any of the other text (this includes not messing with it’s formatting).

Answer 1

Read all, make a backup copy and then write line by line checking the current block status (inside/outside)

Sub removeText(ByVal siteName)
    Dim fileName As String = "hosts.txt"
    Dim startMark As String = "##" + siteName + "#start#"
    Dim stopMark As String = "##" + siteName + "#stop#"

    ' A backup first    
    Dim backup As String = fileName + ".bak"
    File.Copy(fileName, backup, True)

    ' Load lines from the source file in memory
    Dim lines() As String = File.ReadAllLines(backup)

    ' Now re-create the source file and start writing lines not inside a block
    Dim insideBlock as Boolean = False
    Using sw as StreamWriter = File.CreateText(fileName)
        For Each line As String in lines
            if line = startMark
               ' Stop writing
               insideBlock = true 

            else if line = stopMark
               ' restart writing at the next line
               insideBlock = false 

            else if insideBlock = false
               ' Write the current line outside the block
               sw.WriteLine(line) 
            End if
        Next         
    End Using
End Sub