How to Play a section of the WPFmediaElement

I need to play a section of the Mediaelement for example from the second 0:45 to 0:55 sec

I tried using the mediaelement position property here is the code

            Dim mytimeline As New MediaTimeline
            Dim mc As MediaClock

            FReveal1.Visibility = Windows.Visibility.Visible

            FReveal1.Source = New Uri("videos\Front-Game-Answer-Reveals.wmv", UriKind.Relative)

            FReveal1.P开发者_如何转开发osition = New TimeSpan(0, 0, 4)

            mytimeline.Source = FReveal1.Source
            mytimeline.Duration = (TimeSpan.FromMilliseconds(5000))
            mc = myTimeLine.CreateClock()
            FReveal1.Clock = mc
            FReveal1.Play()

But I get the following error : "Cannot perform this operation while a clock is assigned to the media player."

Is there another way to do this ?

Thanks

Would something like this work?

    var StartTime = new TimeSpan(0, 0, 45);
    var EndTime = new TimeSpan(0, 0, 55);

    theMediaElement.Position = StartTime;
    theMediaElement.Play();

    while (theMediaElement.Position != EndTime)
    {
        // chill and let it play
     }

    theMediaElement.Stop();

EDIT: I should probably add that this is a bit cowboy.