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Tag: Silverlight

SharePoint Tools for Windows Azure, Visual Studio, jQuery, and HTML5

As I mentioned in my last post, at the recent SharePoint 2011 conference, I attended a number of sessions where Visual Studio played a major role. Andrew Connell articulated design patterns around using SharePoint with Windows Azure, Ted Pattison showed patterns around jQuery, HTML5 and oData, and Eric Shupps used the performance testing tools in VS2010 to show the impact of performance tweaks.

In all of the sessions mentioned above, reference was made to add ins, extensions, or other tools that make working with SharePoint and Azure a great deal easier. I took note of most of them, and in the process of summarizing them, thought that I should amalgamate them with my own current list of dev tools, and post it here. Extensions can and should be installed via the extensions manager in Visual Studio, and I’ll note them below.

Cloudberry Utility for working with Azure BLOB Storage. Makes moving files to/from blob storage simple
Visual Studio 2010 SharePoint Power Tools* Adds a sandboxed Visual Web Part item template and other enhancements.
CKS Development Tools for SharePoint* Community led effort that includes many Tools and templates for SharePoint development
CAML Intellisense for VS2010* Adds Intellisense to VS2010 for those of use still stuck with CAML
Visual Studio 2010 Silverlight Web Part* Project Template for writing Silverlight web parts – both full trust and sandboxed supported
Web Standards Update for Visual Studio 2010 SP1* Adds Intellisense for HTML5 and CSS3 to VS2010
SharePoint Timer Job Item* Supports the creation of administrative timer jobs in SharePoint 2010
SharePoint 2010 and Windows Azure Training Course Training course to get up to speed on working with SharePoint 2010 and Windows Azure
jQuery Libraries Main libraries for working with jQuery
jQuery UI Library  UI controls for use with jQuery
jQuery Templates Add in for the templating of controls in jQuery
Modernizr Open source project to allow older browsers to work with HTML5/CSS3 elements


*Available through the Visual Studio Extension Manager

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Election Mapping In The Cloud With Silverlight and Azure

I have been know to get involved with local politics from time to time. About 5 weeks ago, when a federal election was called here in Canada, I decided to build an application that would help local campaign scrutineers get their results in quickly and easily. Election night results and turnout information is notoriously difficult to collect and keep.

An election campaign in Canada is an interesting thing. It is essentially a company that is created, runs for 5 weeks, and then disappears. A cloud solution seemed to be the perfect answer.

I’ll talk more about the application in a future post, but once the application was built, it attracted the interest of one of the major media organizations in Canada, PostMedia. The only thing that they wanted added was mapping.

Another few days of work with the Bing Maps Silverlight control, and we had a couple of fairly interesting apps ready for public consumption. They’re currently available on the PostMedia website here:

and here:

Basically, you can see the results for the last two federal elections on a national basis, or on a poll by poll basis for individual ridings.

In case PostMedia removes these links after the current election, you can see the same applications here:

More later…

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Using Silverlight and the SharePoint Client Object Model With Anonymous Access

One of the nicer features that SharePoint 2010 brought with it was the Client Object Model. Previously, all custom code had to either run on the server, using the SharePoint API. As an alternative, you could call the SharePoint SOAP web services from a client application, but in many cases, they left a little to be desired. The client object model brings the richness of the SharePoint API to client side development using either the full .NET framework, Silverlight, or jQuery.

Why is client side development important? Well, simply put, if you want to write an application or an add on for SharePoint, and you want it to run in both on-premise installations and in Office 365, it’s pretty much your only option, because you can’t deploy custom code to SharePoint Online. (OK, you can run sandboxed code in the cloud, but that brings its own set of severe limitations).

There are some great tutorials out there about working with the SharePoint Client Side Object Model (CSOM), so I’m not going to go into that here, but Tobias Zimmergren has an excellent getting started post – Getting Started With The Client Object Model. His example outlines using it with with the .NET CLR version, which is almost identical to Silverlight. As always, it’s the almost part that gets you. But more about that later.

There are a number of extra considerations when using the CSOM with an anonymous site. Since the code is executing on the client side, obviously the data needs to be accessible anonymously. Before we even touch the code, there are a number of things to check on the site itself.

1. Ensure that anonymous access is enabled

This may seem obvious, but it’s worth stating. Anonymous access needs to be enabled at both the web application level, and at the site collection level. One less that clear thing is that the option for enabling it at the site collection level does not even appear until it has been enabled at the application level. Randy Drisgill has an excellent post on how to do this here. As a best practice, I maintain one zone (usually the default) that uses Windows authentication, and my external zone, which allows ONLY anonymous access.

2. Turn off the ViewFormPagesLockDown feature

SharePoint publishing sites are designed to serve up pages, and to ONLY serve up pages to anonymous users. Standard SharePoint list items and forms cannot by default be accessed by anonymous users. This behaviour is controlled by the ViewFormPagesLockdown feature. This feature is enabled by default for publishing sites.

If the Silverlight application will be accessing any SharePoint list data, we will need to turn this feature off. Keep in mind that anonymous users will then have access to content stored in the site if they know how to access them, so you may want to use distinct anonymous access levels on some of your lists/libraries.

To turn off this feature, open a command prompt on your SharePoint server, and enter the following (replacing urlofsite with your url):

stsadm -o deactivatefeature -url http://urlofsite -name ViewFormPagesLockDown

Once you perform this step, you may need to re-set the anonymous access level for the site collection, as it doesn’t always pick up right away.

3. Allow GetItems() calls

For some bizarre (in my opinion…) reason, calls to the GetItems function is disabled by default for anonymous users. Waldek Mastykarz has a post about this issue, and what to do about it, which boils down to the following 3 lines of Powershell.

   1: $wa = Get-SPWebApplication -Identity "http://sharepoint" 

   2: $wa.ClientCallableSettings.AnonymousRestrictedTypes.Remove([Microsoft.SharePoint.SPList], "GetItems") 

   3: $wa.Update()

This will remove this restriction. Replacing “Remove” with “Add” will add it back.

4. Run the Application in Context

In order to work with the CSOM you will need to instantiate an SPContext object. This is the starting object for working with SharePoint objects. You can do this one of two ways. If you’re running the Silverlight application directly from a client (likely in development mode) or out of browser, you use its New constructor with the URL of the site as an argument.

_Context = New ClientContext(_URL)


If, However, you’re running from a SharePoint page, or a web part, you can use the current context.

_Context = ClientContext.Current

In Tobias’s tutorial mentioned above, he indicates that you can control the authentication mode through the AuthenticationMode property of the SPContext object. Possible values are Anonymous, Default, and Forms. As luck would have it, this property is not available to the Silverlight implementation of the SPContext object.

When working as an authenticated user, both options are available to you, but anonymous access only works with the second option. This makes debugging with anonymous sites difficult, as you need to either use a web part project, or copy your compile XAP file to the server manually. However, it’s only one line of code to change, so its entirely feasible to almost all of the development on the internal zone, and remember top change the mechanism before deploying to the anonymous zone.

5. Ensure That All of Your Resources Are Available.

If you’ve ever worked with an external site you’re familiar with the need to check in and approve all public facing content. It’s no different here. You need to ensure that all of the resources used by your application are available to anonymous users. I normally just try to load them all manually in a browser.

Once all of these steps are completed, you should be good to go with your anonymous site.

I wanted to add one other pointer here, although it has nothing to do with anonymous access. When you’re working with the CSOM, all of your calls are made asynchronously. This means that you make a request, and the result calls back into another method of your code. If you’re data binding, and showing results on screen, you will want to show the result as soon as it comes back. The problem is that many calls happen on a background thread, and when the try to access a data bound object, you’ll get the following error:

UnauthorizedAccessException: Invalid cross-thread access in Silverlight application

The trick is to force the update to happen on the UI thread. Steve Willcock at StackOverflow answered a similar question that includes a handy little helper object for forcing execution on the UI thread.

You don’t have to do client side development with SharePoint, but there are many advantages to doing so. The coming release of Office 365 makes it that much more compelling.