title: Automatic Implemented Property leads to a Null Reference while full written Property does not
body: <p>Could anyone tell me why executing this</p>
  
  <pre><code>Module Module1
      Sub Main()
          Dim currentSourceData As New SourceData
          currentSourceData.datafiles.Add("234")
      End Sub
  End Module
  </code></pre>
  
  <p>Does give me</p>
  
  <blockquote>
    <p>System.NullReferenceException: 'Object reference not set to an instance of an object.'</p>
  </blockquote>
  
  <p>When I use automatic implemented prpoerties</p>
  
  <pre><code>Public Class SourceData
      Public Property datafiles() As List(Of String)
  End Class
  </code></pre>
  
  <hr>
  
  <p>But it does not when I use a property fully written:</p>
  
  <pre><code>Public Class SourceData
      Private _datafiles As New List(Of String)
      Public Property datafiles() As List(Of String)
          Get 
             Return _datafiles
          End Get
          Set(value As List(Of String))
              _datafiles = value
          End Set
      End Property
  End Class
  </code></pre>