'Beispiel: VB .Net - Zuordnungen der IP-Adressen zu Hostnamen pruefen ' Option Explicit On Option Strict On Imports System.IO Imports System.Text.RegularExpressions Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _ Handles Button1.Click Dim TList As New List(Of String) TList = ParseHostnamesInHostfile() If TList IsNot Nothing Then For Each items As String In TList Me.TextBox1.Text &= items Next Else MessageBox.Show("Fehler in der Auflistung.", "Info") End If End Sub Private Function ParseHostnamesInHostfile() As List(Of String) Dim Filename As String = "" Try If System.Environment.OSVersion.VersionString().StartsWith("Microsoft Windows NT") Then Filename = String.Format( _ "{0}{1}drivers{1}etc{1}hosts", _ System.Environment.GetFolderPath(Environment.SpecialFolder.System), _ Path.DirectorySeparatorChar _ ) If Not System.IO.File.Exists(Filename) Then Return Nothing Else Dim Content As String = "" Using tr As TextReader = File.OpenText(Filename) Content = tr.ReadToEnd() End Using Dim query As String = "(?<ip>(\d{1,3}\.){3}\d{1,3})\s+(?<name>(\S+))" Dim regex As Regex = New Regex(query) Dim mc As MatchCollection = regex.Matches(Content) Dim TList As New List(Of String) For Each items As Match In mc If items.Length <> 0 Then TList.Add( _ items.Groups("name").ToString() & Convert.ToChar(9) & _ items.Groups("ip").ToString() & System.Environment.NewLine _ ) End If Next Return TList End If Else Return Nothing End If Catch ex As IOException MessageBox.Show(ex.Message.ToString(), "IOException") Catch ex As Exception MessageBox.Show(ex.Message.ToString(), "Exception") End Try Return Nothing End Function End Class