Provides a unique identifier for markup elements. In many scenarios, this unique identifier is used by XAML localization processes and tools.
<object x:Uid="identifier"... />
|A manually created or autogenerated string that should be unique in a file when it is interpreted by an |
x:Uid is defined as a directive. For more information, see [MS-XAML] Section 5.3.6.
x:Uid is discrete from
x:Name both because of the stated XAML localization scenario and so that identifiers that are used for localization have no dependencies on the programming model implications of
x:Name is governed by the XAML namescope; however,
x:Uid is not governed by any XAML language defined concept of uniqueness enforcement. XAML processors in a broad sense (processors that are not part of the localization process) are not expected to enforce uniqueness of
x:Uid values. That responsibility is conceptually on the originator of the values. The expectation of uniqueness of
x:Uid values within a single XAML source is reasonable for consumers of the values, such as dedicated globalization processes or tools. The typical uniqueness model is that
x:Uid values are unique within an XML-encoded file that represents XAML.
Tools that have significant knowledge of a particular XAML schema can choose to apply
x:Uid only for true localizable strings, instead of for all cases where a text string value is encountered in markup.
Frameworks can specify a particular property in their object model to be an alias for
x:Uid by applying the attribute UidPropertyAttribute to the defining type. If a framework specifies a particular property, it is not valid to specify both
x:Uid and the aliased member on the same object. If both
x:Uid and the aliased member are specified, the .NET Framework XAML Services API typically throws XamlDuplicateMemberException for this case.