How do you force Firefox to not cache or re-download a Silverlight XAP file?

Question

When working with Silverlight, I\'ve noticed that Firefox will cache the XAP file, so if I do an update, a user may be stuck using an outdated version. Is there a way to fo

Answer 1

The query string works perfectly, but I wouldn't use DateTime.Now, because it forces the user to re-download the app every time. Instead, we use the following:

protected void Page_Load(object sender, EventArgs e)
{
    var versionNumber = Assembly.GetExecutingAssembly().GetName().Version.ToString();
    this.myApp.Source += "?" + versionNumber;
}

This way all you have to do is increment the version number in the AssemblyInfo.cs file.

Answer 2

For me, the best answer is from Chris Cairns. I've just adapted it a little, calling ToString and GetHashCode, generating an ID to the timestamp:

<param name="source" value="ClientBin/App.xap?<%= System.IO.File.GetLastWriteTime(Server.MapPath("ClientBin/App.xap")).ToString().GetHashCode()%>" />

Works just fine!

Answer 3

You can append the source url in the object tag with the last-write date of the XAP file. Check the code at my blog.

Answer 4

I'm getting this to work by a combination of the suggestions above:

1. Set meta tag cache-control/pragma http-equiv attributes to 'No-Cache'
2. Use an ASP.NET page to host the silverlight control (as opposed to an html page)

3. Set the Source property of the ASP.NET Silverlight control in the code behind, appending a time stamp to the .xap url e.g.

   Silverlight1.Source = "ClientBin/MyApplication.xap?" + DateTime.Now.ToString("dd-MM-yy-HH:mm:ss");

Answer 5

A super simple idea: just add a fake query string to the url.

<param name="source" value="app.xap?r12345"/>

Most servers should ignore it and server the file normally--depends on your server. If you get really clever, you could make the hosting page dynamic and automatically append a tick-count or date-time string to the query string. This ensures that you get caching when you want it, but force a download when there's a change.

Ideally, your server should do this for you. But if not...

Answer 6

So far, the only solution that I have found, once the problem occurs, is to clear the Firefox cache.

A better solution would be much better.