Play the silverlight player from outside the silverlight object - asp.net

Question

I have a simple Silverlight player that uses the MediaElement. For reasons out of my control, they want to be able to have all the play/pause/stop, volume controls etc. based in the ASP.NET code and not be built in Silverlight. I embed the Silverlight in my aspx as follows:
<object id="SilverlightPlayer" data="data:application/x-silverlight,"
type="application/x-silverlight-2" width="750" height="460" >
<param name="source" value="ClientBin/VideoPlayer.xap"/>
<param name="EnableGPUAcceleration" value="true" />
<param name="OnResize" value="HandleResize" />
<param name="autoUpgrade" value="true" />
<param name="initParams" id="SLInitParameters" value='video=MyVideo.wmv' />
</object>
I want to have the user click a "Play" button in the ASPX and it will tell the Silverlight player to play the video. (Same kind of thing for all the other buttons) I have been unable to find out how to do this anywhere since everyone it seems builds these controls into their Silverlight.
Any help is greatly appreciated.
UPDATE:
I am using the following to recreate the silverlight:
function CreateSilverlight(hostElement, source, initParams) {
var pluginId = hostElement.id + "PluginId";
hostElement.innerHTML = Silverlight.createObject(source, null, pluginId,
{
width: '750',
height: '460',
background: 'black',
isWindowless: true,
alt: '<!--Silverlight not installed-->',
data: 'data:application/x-silverlight,',
type: 'application/x-silverlight-2',
EnableGPUAcceleration: true,
version: '4.0',
autoUpgrade: true
},
{ onError: null, onLoad: null, OnResize: HandleResize },
initParams, hostElement.id);
}
So I don't have the reference to the object.

Answer 1

In the constructor of your silverlight page on which the media element appears, call:
HtmlPage.RegisterScriptableObject("player", this)
Then, you can add methods to your page like this:
[ScriptableMember]
public void Play()
{
this.MediaElement.Play();
}
[ScriptableMember]
public void Pause()
{
this.MediaElement.Pause();
}
[ScriptableMember]
public void Stop()
{
this.MediaElement.Stop();
}
Those [ScriptableMember] attributes are important. Then, from javascript, you can do:
var slApp = document.getElementById("SilverlightPlayer");
slApp.player.Play();
That would call the exposed "Play" method, which in turn tells the MediaElement to Play().

Answer 2

You can communicate from HTML to Silverlight via Javascript through the HtmlPage.Window.Invoke() method. Check out this link.

Answer 3

I didn't need to reload the silverlight control to get it to load a different video. I just needed to pass a new media path to the silverlight mediaElement.Source via the JS to silverlight bridge. I also solved my issue of loading a video passed to the page by adding to invoke a js function once the SL was loaded on the screen.