Category Archives: Silverlight

Related to Silverlight (or WPF) or XAML development or tooling

You can’t add a reference to Microsoft.WindowsAzure.StorageClient.dll as it was not build against the Silverlight runtime

Are you developing Silverlight apps that would like to talk directly to Windows Azure APIs? That is perfectly legal, using the REST API. But if you want to use the handy-dandy Windows Azure Managed Libraries – such as Microsoft.WindowsAzure.StorageClient.dll to talk to Windows Azure Storage – then that’s not available in Silverlight.

As you may know, Silverlight assembly format is a bit different than straight-up .NET, and attempting to use Add Reference from a Silverlight project to a plain-old-.NET assembly just won’t work. Instead, you’ll see something like this:

Visual Studio error message from use of Add Reference in a Silverlight project: "You can’t add a reference to Microsoft.WindowsAzure.StorageClient.dll as it was not build against the Silverlight runtime. Silverlight projects will only work with Silverlight assemblies."

If you pick a class from the StorageClient assembly – let’s say, CloudBlobClient – and check the documentation, it will tell you where this class is supported:

Screen clipping from the StorageClient documentation with empty list of Target Platforms

Okay – so maybe it doesn’t exactly – the Target Platforms list is empty – presumably an error of omission. But going by the Development Platforms list, you wouldn’t expect it to work in Silverlight.

There’s Always REST

As mentioned, you are always free to directly do battle with the Azure REST APIs for Storage or Management. This is a workable approach. Or, even better, expose the operations of interest as Azure services – abstracting them as higher level activities. You have heard of SOA, haven’t you? 🙂


Silverlight exceeds 50% penetration

According to RIAStats, a version of Silverlight is now detected on more than half of the browsers sampled! This is a telling milestone as installations of Silverlight continue to grow – drawing inexorably closer to that of Adobe Flash which currently enjoys installations on around 97% of browsers.

If you look at the graphic, and you consider the “not detected” section, it reads 49.99%, which means that the sum of those detected is better than half.


At PDC 2009 in November, Scott Guthrie announced that Silverlight penetration was up to around 45%, up from around 30% in the summer. These RIAStats numbers feel in line with that.

Of course, I know this doesn’t “prove” Silverlight is really on more than 50% of browsers, as RIAStats are not a perfect reflection of the web as a whole, but it seems an interesting milestone nonetheless.

Silverlight has been in the wild for 863 days: Silverlight was released for real (RTW, or “released to web”) on 05-Sep-2007, followed thirteen months later by Silverlight 2 RTW 14-Oct-2008, then less than nine months later we saw Silverlight 3 on 09-July-2009. Silverlight 4 is in beta – maybe Microsoft will announce its release at MIX10 in mid-March? If they do, that would be on a similar release rhythm as from Silverlight 2 to Silverlight 3.

Silverlight’s installed base will also get another boost from the 2010 Winter Olympics next month as well. (And Silverlight 2 shipped shortly after the 2008 Summer Olympics.)

It is interesting to note that another tracking site – – not only shows the penetration lower – and doesn’t agree on any of the numbers – but also doesn’t even agree on relative installed base across versions [EDIT: after Comment from Travis Collins, added in Silverlight 4 = 0.04 for RIAStats]:

RIAStats StatOwl
Silverlight 1 0.62 1.39
Silverlight 2 1.91 9.73
Silverlight 3 47.44 23.85
Silverlight 4 (beta) 0.04 (<1 pixel) not shown, or 0%
Undetected (reported) 49.99 65.03%

I’m not sure why they don’t agree – perhaps differences in sample sizes, sampling methodology, or due to different audiences being sampled.

Also, if you check the math yourself, you’ll see the values shown don’t tie down perfectly for RIAStats (though they do for StatOwl); if you add up the individual Silverlight versions along with the Undetected, you won’t get exactly 100%. Some sort of rounding errors I assume. [EDIT: See explanation in Comment from Travis Collins, RIAStats creator.] But I also assume that the Undetected = 49.99% is most likely right (at least not wrong due to a rounding error, since it is harder to round wrong there).

EDIT 01-Feb-2010: Found an interesting, relevant post on Cool facts about Silverlight penetration / mindshare from