298 Microsoft Visual Studio 2010: A Beginner’s Guide
The crossdomain.xml policy was created for Adobe Flash applications and can be used
with Silverlight applications too. Here’s an example:
<!DOCTYPE cross-domain-policy
SYSTEM "http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<allow-access-from domain="*" />
<allow-http-request-headers-from domain="*" headers="*" />
</cross-domain-policy>
When designing Silverlight, Microsoft recognized that the crossdomain.xml
file wasn’t flexible enough and added support for another type of policy called
clientaccesspolicy.xml. Here’s an example:
<?xml version="1.0" encoding="utf-8"?>
<access-policy>
<cross-domain-access>
<policy>
<allow-from http-methods="*">"
<domain uri="*"/>
</allow-from>
<grant-to>
<resource path="/" include-subpaths="true"/>
</grant-to>
</policy>
</cross-domain-access>
</access-policy>
This clientaccesspolicy.xml listing allows all domains to access all site content that
isn’t already secured by other means. You can restrict access by replacing the * in the
domain uri with an allowable domain. Further, you can replace the resource path with a
path on the site to restrict access to specific folders. Add more policy elements to this file
to add more domains and paths.
Summary
This chapter explains how to run a Silverlight application. You learned how to use the
MediaElement control and how to build UIs using the same techniques as in WPF. The
OOB functionality allows you to run Silverlight from your desktop. A section describes
deploying the Silverlight application to a Web server.
We’ve discussed a couple Web technologies already: ASP.NET MVC in Chapter 9 and
Silverlight in this chapter. The next chapter shows you another Web technology: WCF
Web services.