Imports System.IO
Public Class Form1
    Const CryptoKey As String = "StefanHutterUnternehmensberatung8808Pfaeffikon"
    Private Sub LadenToolStripMenuItem1_Click(sender As Object, e As EventArgs) Handles LadenToolStripMenuItem1.Click
        If OpenFileDialog1.ShowDialog = DialogResult.OK Then
            Read_File(OpenFileDialog1.FileName, False)
        End If
    End Sub

    Private Sub LadenToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles LadenToolStripMenuItem.Click
        If OpenFileDialog1.ShowDialog = DialogResult.OK Then
            Read_File(OpenFileDialog1.FileName, True)
        End If
    End Sub
    Private Sub Read_File(ByVal filename As String, ByVal Crypted As Boolean)
        Dim reader = File.OpenText(filename)
        Me.TextBox1.Text = ""
        Dim line As String = Nothing

        Dim lines As Integer = 0
        Dim i = 0
        While (reader.Peek() <> -1)
            line = reader.ReadLine()
            If Crypted Then
                line = Crypto.DecryptText(line, CryptoKey)
            End If
            If i > 0 Then Me.TextBox1.AppendText(vbCrLf)
            i = i + 1
            Me.TextBox1.AppendText(line)
        End While
        reader.Close()

    End Sub

    Private Sub SpeichernToolStripMenuItem1_Click(sender As Object, e As EventArgs) Handles SpeichernToolStripMenuItem1.Click
        If SaveFileDialog1.ShowDialog = DialogResult.OK Then
            save_file(SaveFileDialog1.FileName, False)
        End If
    End Sub

    Private Sub SpeichernToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles SpeichernToolStripMenuItem.Click
        If SaveFileDialog1.ShowDialog = DialogResult.OK Then
            Save_File(SaveFileDialog1.FileName, True)
        End If

    End Sub

    Private Sub Save_File(ByVal Filename As String, ByVal Crypted As Boolean)
        Dim file As System.IO.StreamWriter
        file = My.Computer.FileSystem.OpenTextFileWriter(Filename, False)
        For i = 0 To Me.TextBox1.Lines.Count - 1
            Dim s As String
            s = Me.TextBox1.Lines(i)
            If Crypted Then s = Crypto.EncryptText(s, CryptoKey)
            file.WriteLine(s)
        Next
        file.Close()
    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    End Sub
End Class