ExtensionPart.Source Property

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Gets or sets the file name or URI of the external library package.

Namespace:  System.Windows
Assembly:  System.Windows (in System.Windows.dll)


Public Overrides Property Source As Uri
public override Uri Source { get; set; }
<ExtensionPart Source="string" />

Property Value

Type: System.Uri
The file name or URI of the external library package.


The Source property indicates the name of an application library package or an absolute URI that identifies an application library package. Files identified by name only are retrieved from the same server location as the .xap file.

For more information, see How to: Use Application Library Caching.


Files identified by URI must be on the same domain as the .xap file or on a domain with a cross-domain policy file. For more information, see HTTP Communication and Security with Silverlight.

Version Information


Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0


For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.