Visual Basic

Dim lines() as String = _
  myBigString.Split(System.Environment.NewLine)

Dim i as integer
For i = 0 to lines.Length - 1
    '--do something with the line
    DoSomething(lines(i))
Next

Dim sr as System.IO.StringReader = _
  new System.IO.StringReader(myBigString)

Dim line as String
'--read the first line from the string
line = sr.ReadLine()
Do While Not (line Is Nothing)
    '--do something with the line
    DoSomething(line)
    '--read the next line from the string
    line = sr.ReadLine()
Loop

Private Sub mnuFileOpen_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuFileOpen.Click
    If ofdOpenFile.ShowDialog = DialogResult.OK Then
        fileName = ofdOpenFile.FileName
        Dim openFile As New StreamReader(fileName)
        txtEdit.Text = openFile.ReadToEnd()
        openFile.Close()
    End If
End Sub

Private Sub mnuFileSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuFileSave.Click
    If Not fileName.Equals(String.Empty) Then
        Dim saveFileWriter As StreamWriter = File.CreateText(fileName)
        Dim strReader As New StringReader(txtEdit.Text)
        saveFileWriter.Write(strReader.ReadToEnd)
        saveFileWriter.Flush()
        saveFileWriter.Close()
        strReader.Close()
    End If
End Sub