FrameworkElement::Tag Property
Gets or sets an arbitrary object value that can be used to store custom information about this object.
Namespace: System.Windows
Assembly: System.Windows (in System.Windows.dll)
Dependency property identifier field: TagProperty
This property is similar to Tag properties in other programming models. Tag is intended to provide a preexisting property location where you can store some basic custom information about any FrameworkElement without requiring you to derive from FrameworkElement or an intermediate class.
Because this property takes an object, a property element usage is required to set the Tag property in XAML to anything other than an object with a type converter, such as a string. Objects used in this manner are typically not within the standard Silverlight XAML namespaces and therefore may require mapping an external namespace in order to be introduced as XAML object elements.
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.