Public Class Form1
    Public pfad2 As String
    Public pfad As String
    Private Sub BeendenToolStripMenuItem_Click(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles BeendenToolStripMenuItem.Click
        Me.Close()
    End Sub
 
    Private Sub DateiÖffnenToolStripMenuItem_Click(ByVal sender As _
      System.Object, ByVal e As System.EventArgs) Handles _
      DateiÖffnenToolStripMenuItem.Click
        OpenFileDialog1.ShowDialog()
    End Sub
    Private Sub DirListBox1_SelectedIndexChanged(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles DirListBox1.SelectedIndexChanged
        pfad = DirListBox1.Path
        FileListBox1.Path = pfad
    End Sub
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Dim rtb As RichTextBox = Me.RichTextBox1
        rtb.AcceptsTab = True
        rtb.SelectionTabs = New Integer() {50}
        For Each dr As String In IO.Directory.GetLogicalDrives()
            ComboBox1.Items.Add(dr)
        Next
    End Sub
 
    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        pfad2 = ComboBox1.Text
        DirListBox1.Path = pfad2
    End Sub
 
    Private Sub OpenFileDialog1_FileOk(ByVal sender As System.Object, ByVal e _
      As System.ComponentModel.CancelEventArgs) Handles OpenFileDialog1.FileOk
        Dim dateiname As String
        dateiname = OpenFileDialog1.FileName
 
        Dim fileReader As String
        fileReader = My.Computer.FileSystem.ReadAllText(dateiname)
        RichTextBox1.Text = fileReader
    End Sub
End Class