WPF and Windows Media Player COM control

The WMPLib offers direct control to Windows Media Player to your C# applications. This provides a rich set of events and controls that is really useful if you would like to create a custom media player.

The code I wrote scans the computer (My Music) and builds up a library of artists, albums and songs using the directory structure. Any images found are used to create folder icons. I later found out that it is possible to access the Windows Media Player media collection library to access this information so next time I´ll probably use that) However, this requires the albums to be imported/added to the Windows Media Player.

There is a few neat trick available when using the WMP. One is that it sends events when ever the player state changes (see list of events). This enabled me to initiate a progress bar that displays the current position in the song (code 3) as well as skipping to the next song when a the current playing song was completed (code 8).

To add WMP in you code

Using WMPLib;

WindowsMediaPlayer _wmp;

public MyApp()
{
_wmp = new WindowsMediaPlayer();
// The event below tells WMP to call your own MediaProcess code
// when the WMP player changes state
_wmp.PlayStateChange += new _WMPOCXEvents_PlayStateChangeEventHandler(MediaProcessChange);

}
private void MediaProcessChange(int newState)
{
//The integer "newState" contains the state of the media player, ranging from 1 to 11
// see http://msdn2.microsoft.com/en-us/library/bb249361(VS.85).aspx for mor infomation

switch(newState)
{
// case 1: // Stopped
// case 2 : // Paused

case 3 : // Song starts playing

progress.Maximum = _wmp.currentMedia.duration;
progress.SetValue(ProgressBar.ValueProperty, _wmp.controls.currentPosition);

BackgroundWorker _worker = new BackgroundWorker();
_worker.WorkerReportsProgress = false;
_worker.WorkerSupportsCancellation = true;

_worker.DoWork += delegate(object s, DoWorkEventArgs args)
{
while (_wmp.controls.currentPosition <>
{
// Dispatcher to update the U.I progressbar every two seconds
Dispatcher.BeginInvoke(DispatcherPriority.Background, (SendOrPostCallback)delegate { progress.SetValue(ProgressBar.ValueProperty, _wmp.controls.currentPosition); }, null);
Thread.Sleep(2000);
}
}; // End delegate
_worker.RunWorkerAsync();
break;

// case 4 : // ScanFordward
// case 5 : // ScanBackwards
// case 6 : // Buffering
// case 7 : // Waiting

case 8: // Song ended, play next

PlayNextSong(null,null);
break;

// case 9 : // Transitioning
// case 10 : // Ready
// case 11 : // Reconnecting
}
}

The "progress" object is a XAML added obj of the type ProgressBar. These handy U.I elements can be set to the maximum value (instead of 1 to 100) The maximum value I set to the entire lenght of the song. This way the current position scale to the bar.

There is a good tutorial for making a media player at Pauls Blog. Additionally, another custom media player by Sacha Barber. The MSDN network has extensive API info as always (but perhaps in a really boring format)

Gaze Media Player

The component I´ve been working on is now capable of the basics. Great feeling just looking a song titles and then skipping through the playlist by gaze =) There is room for improvements, would be nice have a component like a slider where one could go to a specific part of the song. (don´t know how many times I´ve been playing guitar to a song while learning it and going back and forth between mouse and guitar. Let´s see what a weekend could do =)

Screenshot of the music player component, layout not finalized.. Updated version has a song progression bar and volume controls.

The play-button houses another ellipse shaped menu with the regular controls for (next, previous, play, stop)

GazeMemory v0.1a on its way

The extra time spent on developing the Custom Controls for Windows Presentation Foundation (WPF) paid off. What before that took days to develop can now be build within hours. Today I put together a gaze version of the classic game Memory which is controlled by dwell-time (prologed fixation) The "table" contains 36 cards, i.e 18 unique options. By fixating on one card a smooth animation will make the globe on the front of the card to light up and after fixating long enough (500ms) if will show the symbol (flags in first version) After selecting the fist card another is fixated and the two will be compared. If they contain the same symbols then remove them from the table. If not, turn them back over again. The interface provides several feedback mechanisms. Upon glancing the border around the buttons begins to shine, when fixating long enough the dwell time function is activated and illustrated by a white glow that smoothly fades up surrounding the globe.

The Custom Control that will be named GazeButton is to be further developed to support more features such as a configurable dwell-time, feedback such as animations, colors etc. The time spent will be returned tenfold when later on. I plan to release these components as open source as soon as they reach better and more stable performance (ie. production quality with documentation)

Lessons learned so far involves Dependecy properties which is very important if you'd like to develop custom controls in WPF. Animation control and triggers and getting more into DataBinding which looks very promising so far.

Links:
Recommended guidelines for WPF custom controls
Three ways to build an image button
Karl on WPF

Screenshot of the second prototype of the my GazeMemory game