x:Code Intrinsic XAML Type
Allows placement of code within a XAML production. Such code can either be compiled by any XAML processor implementation that compiles XAML, or left in the XAML production for later uses such as interpretation by a runtime.
The code within the x:Code XAML directive element is still interpreted within the general XML namespace and the XAML namespaces provided. Therefore, it is usually necessary to enclose the code used for x:Code inside a CDATA segment.
x:Code is not permitted for all possible deployment mechanisms of a XAML production. In specific frameworks (for example WPF) the code must be compiled. In other frameworks, x:Code usage might be generally disallowed.
For frameworks that permit managed x:Code content, the correct language compiler to use for x:Code content is determined by settings and targets of the containing project that is used to compile the application.
WPF Usage Notes
Code declared within x:Code for WPF has several notable limitations:
The x:Code directive element must be an immediate child element of the root element of the XAML production.
x:Class Directive must be provided on the parent root element.
The code placed within x:Code will be treated by compilation to be within the scope of the partial class that is already being created for that XAML page. Therefore all code you define must be members or variables of that partial class.
You cannot define additional classes, other than by nesting a class inside the partial class (nesting is allowed, but it is not typical because nested classes cannot be referenced in XAML). CLR namespaces other than the namespace that is used for the existing partial class cannot be defined or added to.
References to code entities outside the partial class CLR namespace must all be fully qualified. If members being declared are overrides to the partial class overridable members, this must be specified with the language-specific override keyword. If members declared in x:Code scope conflict with members of the partial class created out of the XAML, in such a way that the compiler reports the conflict, the XAML file cannot compile or load.