Public Class Form1
 
    Public Function ReadLine(ByVal filename As String, ByVal line As Integer) _
      As String
 
        Try
            Dim lines As String() = My.Computer.FileSystem.ReadAllText( _
              filename, System.Text.Encoding.Default).Split(vbCrLf)
 
            If line > 0 Then
                Return lines(line - 1)
            ElseIf line < 0 Then
                Return lines(lines.Length + line - 1)
            Else
                Return ""
            End If
        Catch ex As Exception
            Return ""
        End Try
    End Function
 
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles _
      Button1.Click
        If OpenFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OK _
        Then
            If ReadLine(OpenFileDialog1.FileName, 1) = "Otto" Then
                MessageBox.Show("Otto Datei")
            Else
                If ReadLine(OpenFileDialog1.FileName, 1) = "Peter" Then
                    MessageBox.Show("Peter Datei")
                Else
                    MessageBox.Show("flasche Format")
                End If
            End If
 
        End If
    End Sub
 
 
End Class

 ''' <summary>Ermittlung einer bestimmten Zeile in einer Text-Datei</summary>
 ''' <param name="filepath">voller Pfad der zu lesenden Datei</param>
 ''' <param name="linenumber">Index der zu lesenden Zeile (eins-basiert)</param>
 ''' <param name="IgnoreEmptyLines">Leere Zeilen bei Indizierung ignorieren?</param>
 ''' <param name="Message">Fehlermeldung oder Leere Rückgabe</param>
 ''' <returns>gelesene Zeile oder Nothing</returns>
 Private Function ReadLine(ByVal filepath As String, _
                           ByVal linenumber As Integer, _
                          Optional ByVal IgnoreEmptyLines As Boolean = True, _
                          Optional ByRef Message As String = "") As String
 
        If Not IO.File.Exists(filepath) Then
            Message = "Datei nicht gefunden" : Return Nothing
        End If
        If New IO.FileInfo(filepath).Length = 0 Then
            Message = "Leere Datei" : Return Nothing
        End If
        If linenumber < 1 Then
            Message = "Ungültiger Parameter: LineNumber" 
            Return Nothing
        End If
 
        Dim ln As Integer = 0
        Dim enc As System.Text.Encoding = System.Text.Encoding.UTF8
        Dim line As String, ret As String = Nothing
        Try
            Using sr As New IO.StreamReader(filepath, enc, False)
                Do
                    line = sr.ReadLine()
                    If Not IgnoreEmptyLines OrElse _
                       Not line = String.Empty Then
                        ln += 1
                        If ln = linenumber Then ret = line
                    End If
                Loop Until ln = linenumber Or sr.EndOfStream
            End Using
            If ret Is Nothing Then
                Message = "Ungültiger Parameter: LineNumber"
            Else
                Message = ""
            End If
            Return ret
        Catch ex As Exception
            Message = ex.Message : Return Nothing
        End Try
    End Function

  Dim message As String = ""
  Dim line As String = _
       ReadLine("C:\daten\aaa.txt", 1, False, message)
  If line Is Nothing Then
     MsgBox(message)
  Else
     MsgBox(line)
  End If

    Private Sub VerifyFile(ByVal targetFile As String)
        If FileExist(targetFile) Then
            If Not FileEmty(targetFile) Then
                Dim Lines As List(Of String) = ReadFile(targetFile, _
                  System.Text.Encoding.UTF8, True)
                If Lines(0).Contains("otto") AndAlso Lines.Last.Contains("end") _
                Then
                    ' Do something
                Else
                    If MessageBox.Show("Invalid file.", "Error", _
                      MessageBoxButtons.OK) = Windows.Forms.DialogResult.Yes _
                      Then
                        Application.Exit()
                    End If
                End If
            Else
                If MessageBox.Show("File is empty.", "Error", _
                  MessageBoxButtons.OK) = Windows.Forms.DialogResult.Yes Then
                    Application.Exit()
                End If
            End If
        Else
            If MessageBox.Show("File don't exist.", "Error", _
              MessageBoxButtons.OK) = Windows.Forms.DialogResult.Yes Then
                Application.Exit()
            End If
        End If
    End Sub
 
    Private Function FileExist(ByVal filePath As String) As Boolean
        Return IO.File.Exists(filePath)
    End Function
 
    Private Function FileEmty(ByVal filePath As String) As Boolean
        Dim fi As IO.FileInfo = New IO.FileInfo(filePath)
        If fi.Length = 0 Then
            Return True
        Else
            Return False
        End If
    End Function
 
    Private Function ReadFile(ByVal filePath As String, ByVal encoding As _
      System.Text.Encoding, ByVal detectEncoding As Boolean) As List(Of String)
        Return IO.File.ReadAllLines(filePath).ToList
    End Function
 
    Private Function Verify(ByVal value As String, ByVal searchPattern As _
      String) As Boolean
        Return value.Contains(searchPattern)
    End Function

Dim gruß As New Gruß("Mit freundlichen Grüßen, FormFollowsFunction :) ")
gruß.Schow()

Dim gruß As New Gruß("Mit freundlichen Grüßen, FormFollowsFunction :) ")
gruß.Schow()

Dim sr As New StreamReader("d:\irgendwas\textdatei.txt")
Dim strInhalt as String=sr.ReadToEnd
 
If strInhalt.Contains("Otto") Then...<pre><code>

Dim sr As New StreamReader("d:\irgendwas\textdatei.txt")
Dim strInhalt as String=sr.ReadToEnd
 
If strInhalt.StartsWith("Otto") Then...<pre><code>

EALA FREYA FRESENA

Zitat:

Du musst für wichtige Daten jede Zeile einlesen, auf jedes Feld analysieren und entsprechend reagieren. Eine Einzelprüfung auf die erste Zeile reicht nicht wenn es sich um wichtige Daten handelt, das ist eher ein Anhaltspunkt mehr aber auch nicht.

Dim gruß As New Gruß("Mit freundlichen Grüßen, FormFollowsFunction :) ")
gruß.Schow()