weird exception adding an item from a TimelineMarkerCollection to MediaElement.Markers

09-15-2008 4:13 AM |

 Hello,

 I want to add a collection of TimelineMarker objects to MediaElement.Markes collection on the MediaOpened event:

        void mediaElement_MediaOpened(object sender, RoutedEventArgs e)
        {
            this.mediaElement.Markers.Clear();
            foreach(TimelineMarker marker in this.markers)
            {
                this.mediaElement.Markers.Add(marker);      // generates exception
            }

          }

where markers is a TimelineMarkerCollection object which is created before the event is generated (in fact before setting MediaElement.Source).

This however results in an exception generated by Add method:

 System.ArgumentException: Value does not fall within the expected range.
   at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
   at System.Windows.PresentationFrameworkCollection`1.AddDependencyObject(DependencyObject value)
   at System.Windows.Media.TimelineMarkerCollection.Add(TimelineMarker value)
   at TestProject.MediaPlayer.mediaElement_MediaOpened(Object sender, RoutedEventArgs e)

But if I create a new TimelineMarker object everything is fine:

        void mediaElement_MediaOpened(object sender, RoutedEventArgs e)
        {
            this.mediaElement.Markers.Clear();
            foreach(TimelineMarker marker in this.markers)
            {
                TimelineMarker tlm = new TimelineMarker();
                tlm.Text = marker.Text;
                tlm.Time = marker.Time;
                tlm.Type = marker.Type;

                this.mediaElement.Markers.Add(tlm);
            }

         }

I don't understand why a copy of the TimelineMarker created locally works but not an item from a TimelineMarkerCollection.

Re: weird exception adding an item from a TimelineMarkerCollection to MediaElement.Markers

09-15-2008 8:46 AM |

Is the markers collection already added to a mediaelement?

An element can only have 1 parent, that's probably why the error occurs.

(If this has answered your question, please click on mark as answer on this post)

Cheers!
Rob Houweling

My blog

Re: Re: weird exception adding an item from a TimelineMarkerCollection to MediaElement.Markers

09-15-2008 11:14 AM |

Hi,

thanks for your comment. 

markers collection is a member type of my movie player class:

TimelineMarkerCollection markers = new TimelineMarkerCollection();

The clients of my class can add new markers and I thought to save them in a TimelineMarkerCollection. Then, I receive the event that movie is opened so I can add each TimelineMarker in this markers collection to the MediaElement.Markers

Re: Re: weird exception adding an item from a TimelineMarkerCollection to MediaElement.Markers

09-15-2008 1:28 PM |

Can you post your project?

(If this has answered your question, please click on mark as answer on this post)

Cheers!
Rob Houweling

My blog

Re: Re: weird exception adding an item from a TimelineMarkerCollection to MediaElement.Markers

09-16-2008 4:21 AM |

 Here it is: https://code.msdn.microsoft.com/Release/ProjectReleases.aspx?ProjectName=nitescua&ReleaseId=1545

I only have a MediaElement for which I add a marker in MediaOpened event.

As you can see it fails on adding a TimelineMarker object from a TimelineMarkerCollection.

Re: Re: Re: weird exception adding an item from a TimelineMarkerCollection to MediaElement.Markers

09-16-2008 6:41 PM |

 anybody knows why it crashes when using an object from TimlineMarkerCollection

Re: Re: weird exception adding an item from a TimelineMarkerCollection to MediaElement.Markers

09-17-2008 3:41 AM |

Ok, thanks for explanation.

But it's a pitty that you need to add one by one a TimelineMarker to MediaElement.Markers instead of adding a collection

Re: Re: weird exception adding an item from a TimelineMarkerCollection to MediaElement.Markers

12-05-2008 4:27 PM |

 I too am getting an odd error.

This is the message information that is being thrown, with no inner exception at all.

System.ExecutionEngineException was unhandled
  Message="Exception of type 'System.ExecutionEngineException' was thrown."
  InnerException:

The code that generates the error.

public void AddMarker(TimeSpan Time)
        {
            //If the media already has a marker at that time, throw an error
            var _x = (from _m in _media.Markers where _m.Time == Time select _m);
            if(_x.Count() > 0)
                throw new MediaMarkerException("Marker already exists for this time");
            else
            {
                TimelineMarker _tl = new TimelineMarker();
                _tl.Time = Time;
                _media.Markers.Add(_tl);
            } 

I just want to allow for users to create a new marker item for a piece of media.

Re: Re: weird exception adding an item from a TimelineMarkerCollection to MediaElement.Markers

12-09-2008 10:29 AM |

I found the problem, and thought I'd share.

When adding TimelineMarkers to a piece of media the media must be loaded, not just the source defined.  What I ended up doing was creating a keypair list on the control that housed the media item, and on the MediaLoaded event I go through the list and add the markers.