Multiple index searches - vb.net

Question

I have written a code to search for text using the index to not save to the listbox.
I need to add more characters to search.
I need to find the text starting with - and at the end -> this text is not written to the listbox.
They also need to find text beginning with / ** and at the end of * / but this code no longer works.
Dim openfile = New OpenFileDialog() With {.Filter = "Text (*.php)|*.php"}
If (openfile.ShowDialog() = System.Windows.Forms.DialogResult.OK) Then
For Each line As String In File.ReadAllLines(openfile.FileName, Encoding.Default)
'OPEN DIALOG
Next
End If
Dim komentar As Boolean
komentar = False
For Each line As String In File.ReadAllLines(openfile.FileName, Encoding.Default)
'FIND Charakter <!- and stop write to listbox
If Not line.IndexOf("<!-") = -1 Then
komentar = True
End If
If komentar Then --- this wrong
'FIND Charakter --> and afrer write to listbox
If Not line.IndexOf("-->") = -1 Then
komentar = False
End If
' I don't know how to specify another condition to search for other sentences
' that don't write when it finds characters
If Not line.IndexOf("/**") = -1 Then
komentar = True
End If
If komentar Then
If Not line.IndexOf("*/") = -1 Then
komentar = False
End If
Else
ListBox1.Items.Add(line)
End If
This code has the task of opening a file through a dialog box. Before it is loaded into the list box, it searches for text that begins with / ** and ends with * / and this text is not written to the listbox. I still need the listbox not to include sentences starting with so I used if not line.indexof and comment True or False.

Answer 1

I misunderstood your request at first but Andrew Morton's comment made me realise what you were actually asking for. Here's how I might implement it:
Dim terminatorsByInitiator As New Dictionary(Of String, String) From {{"<!--", "-->"},
{"/**", "*/"}}
Dim isComment = False
Dim terminator As String
For Each line In File.ReadAllLines(openfile.FileName, Encoding.Default)
If isComment Then
'Check whether we are at the end of the comment.
If line.EndsWith(terminator) Then
isComment = False
End If
Else
'Get the comment initiator at the start of the line, if there is one.
Dim initiator = terminatorsByInitiator.Keys.FirstOrDefault(Function(s) line.StartsWith(s))
If initiator Is Nothing Then
'This line does not initiate a comment so add it to the list.
ListBox1.Items.Add(line)
Else
'This line does initiate a comment.
isComment = True
'Remember which comment terminator to look for.
terminator = terminatorsByInitiator(initiator)
End If
End If
Next
The use of the Dictionary ensures that you always look for the right comment terminator based on the initiator that was found.