c # using + XmlWriter.Create = «Невозможно получить доступ к закрытому потоку».

Почему это работает:

using (var ms = new MemoryStream())
{
    using (var dummy = new StreamWriter(ms))
    {
        var sw = new StreamWriter(ms);
        sw.WriteLine("Hello World");
        sw.Flush();
        using (StreamReader rdr = new StreamReader(ms))
        {
            ms.Position = 0;
            textBoxExc.Text = rdr.ReadToEnd();
        }
    }
}

но это не работает («Нет доступа к закрытому потоку.»): Единственная разница - var dummy = XmlWriter.Create (ms) вместо var dummy = new StreamWriter (ms)

using (var ms = new MemoryStream())
{
    using (var dummy = XmlWriter.Create(ms))
    {
        var sw = new StreamWriter(ms);
        sw.WriteLine("Hello World");
        sw.Flush();
        using (StreamReader rdr = new StreamReader(ms))
        {
            ms.Position = 0;
            textBoxExc.Text = rdr.ReadToEnd();
        }
    }
}

Трассировка стека:

System.ObjectDisposedException was unhandled by user code
  Message=Cannot access a closed Stream.
  ObjectName=""
  StackTrace:
       w System.IO.__Error.StreamIsClosed()
       w System.IO.MemoryStream.Write(Byte[] buffer, Int32 offset, Int32 count)
       w System.Xml.XmlUtf8RawTextWriter.FlushBuffer()
       w System.Xml.XmlUtf8RawTextWriter.Flush()
       w System.Xml.XmlWellFormedWriter.Close()
       w System.Xml.XmlWriter.Dispose(Boolean disposing)
       w System.Xml.XmlWriter.Dispose()
       w SerializeTest.MainPage.buttonExc_Click(Object sender, RoutedEventArgs e)
       w System.Windows.Controls.Primitives.ButtonBase.OnClick()
       w System.Windows.Controls.Button.OnClick()
       w System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
       w System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)
       w MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)
  InnerException: 

Также это не работает (та же ошибка):

using (var ms = new MemoryStream())
{
     using (var writer = XmlWriter.Create(ms))
    {
        var serializer = new DataContractSerializer(typeof(T));
        serializer.WriteObject(writer, objectToSave);
        writer.Flush();
        ms.Position = 0;
        using (StreamReader rdr = new StreamReader(ms))
        {
            return rdr.ReadToEnd();
        }
    }
}

Трассировка стека:

System.ObjectDisposedException was unhandled by user code
  Message=Cannot access a closed Stream.
  ObjectName=""
  StackTrace:
       w System.IO.__Error.StreamIsClosed()
       w System.IO.MemoryStream.Write(Byte[] buffer, Int32 offset, Int32 count)
       w System.Xml.XmlUtf8RawTextWriter.FlushBuffer()
       w System.Xml.XmlUtf8RawTextWriter.Flush()
       w System.Xml.XmlWellFormedWriter.Close()
       w System.Xml.XmlWriter.Dispose(Boolean disposing)
       w System.Xml.XmlWriter.Dispose()
       w SerializeTest.SerializeToStringTest[T](T objectToSave)
       w SerializeTest.MainPage.button2A_Click(Object sender, RoutedEventArgs e)
       w System.Windows.Controls.Primitives.ButtonBase.OnClick()
       w System.Windows.Controls.Button.OnClick()
       w System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
       w System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)
       w MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)
  InnerException: 

, но это работает (разница только в StreamReader без с использованием ):

using (var ms = new MemoryStream())
{
     using (var writer = XmlWriter.Create(ms))
    {
        var serializer = new DataContractSerializer(typeof(T));
        serializer.WriteObject(writer, objectToSave);
        writer.Flush();
        ms.Position = 0;
        StreamReader rdr = new StreamReader(ms);
        return rdr.ReadToEnd();
    }
}