MSDN Magazine - November 2008 - (Page 38)

{ Random rnd = new Random(); return rnd.Next(0, 100); } } Scriptable members on a plug-in are directly visible to JavaScript code in the page. In Figure 7, you see a JavaScript wrapper for the publicly available interface of the Silverlight plug-in. Any plug-in interested in the interface of the other plug-in can create an instance of the JavaScript wrapper in the figure: ScriptObject so = HtmlPage.Window.CreateInstance("ActionBar"); object result = so.Invoke("invokeGetRandomNumber"); then the need to execute managed code from JavaScript or invoke JavaScript objects from within managed code is a real one. The browser interoperability layer (also known as the HTML bridge) contains a lot of functionality to enable communication between the managed world of Silverlight and the interpreted world of JavaScript. Communication requires marshaling of types and ob- Is there a more direct way to invoke a Silverlight plug-in from another one? Yes, you can opt for the following: HtmlElement plugin = HtmlPage.Document.GetElementById("Silverlight2"); var content = (ScriptObject) plugin.GetProperty("content"); var action = (ScriptObject) content.GetProperty("Action"); action.Invoke("GetRandomNumber"); A Silverlight app that exposes a public managed API is subject to cross-domain access. jects across the layers. At the highest level of abstraction, you find a public API and documentation to explain the few things you need to know to invoke managed code from JavaScript and JavaScript objects from managed code. If you have a special issue, or just want to split hairs as far as implementation details are concerned, you might want to keep an eye on Wilco Bauwer’s informative blog, at wilcob.com. DINO ESPOSITO is an architect at IDesign and the coauthor of Microsoft .NET: Architecting Applications for the Enterprise (Microsoft Press, 2008). Based in Italy, Dino is a frequent speaker at industry events worldwide. You can join his blog at weblogs.asp.net/despos. The final effect is the same. This way, however, you’re making more round-trips between Silverlight and the underlying browser. The Silverlight Base Class Library includes facilities to connect to the browser and the host page and to read information and access the DOM. If you have a Silverlight-centric application, you probably don’t need to do much with the host HTML page. However, if yours is a mixed solution with both ASP.NET AJAX and Silverlight, 38 msdn magazine Cutting Edge http://www.wilcob.com http://weblogs.asp.net/despos http://www.radmin.com/wanted http://www.radmin.com/wanted

Table of Contents Feed for the Digital Edition of MSDN Magazine - November 2008

Contents MSDN Magazine - November 2008 Toolbox CLR Inside Out Data Points Cutting Edge Security Briefs Test Your Security IQ Agile SDL Access Control Utility Spotlight RIA Test Run Wicked Code Foundations Team System End Bracket

MSDN Magazine - November 2008

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