Public Class Form1
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As  _
      System.EventArgs) Handles Button2.Click
        Me.Close()
    End Sub
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As  _
      System.EventArgs) Handles MyBase.Load
        TextBox1.Focus()
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As  _
      System.EventArgs) Handles Button1.Click
 
        Dim f2 As New Form2
        f2.EqualText = Me.TextBox1.Text
        f2.ComboBox1.Items.Add("blablabla")
        f2.ComboBox1.SelectedIndex = 0
        f2.ShowDialog()
 
        TextBox1.Text = ""
        TextBox1.Focus()
 
    End Sub
 
End Class

Public Class Form2
    Private mEqualText As String
 
    Public Property EqualText() As String
        Get
            Return Me.mEqualText
        End Get
        Set(ByVal value As String)
            Me.mEqualText = value
        End Set
    End Property
 
 
 
    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.TextBox1.Focus()
    End Sub
 
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Dim writeStr As String = mEqualText & "," & DateAndTime.Now.ToString & _
        "," & TextBox1.Text & "," & DateAndTime.Now.ToString & "," & _
        ComboBox1.SelectedItem.ToString & vbCrLf
        MessageBox.Show("Barcodes nicht identisch! Bitte neu einscannen.", _
        "Hinweis!", MessageBoxButtons.OK, MessageBoxIcon.Error)
        My.Computer.FileSystem.WriteAllText( _
        My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\BEMIDAT.txt", _
        writeStr, True)
        If TextBox1.Text <> Me.mEqualText Then
            TextBox1.Text = ""
            TextBox1.Focus()
        Else
            Me.Close()
        End If
 
    End Sub
 
End Class