Suggestion: C# static extension methods invokable on class type too
it would be nice if C# supported syntax like:
public static DependencyProperty Register(static DependencyProperty x, string name, Type propertyType, Type ownerType, FrameworkPropertyMetadata typeMetadata)
that is static extension methods for classes, that can be invoked without a class instance (just with the class type), apart from normal extension methods that can be invoked on a class instance.
Then for example I could use it in Silverlight to add to its DependencyProperty class some extra WPF syntax that it currently misses, in order to increase code portability. It would wrap Dr.WPF’s implementation of value coercion for Silverlight’s DependencyProperty. I have the related code at my Compatibility library (http://Compatibility.codeplex.com) and respective NuGet package (http://nuget.org/packages/Compatibility), but the syntactic sugar is missing to achieve source code portability (via WPF and Silverlight projects that include common files via file links) without changes.
Note the "static DependencyProperty" parameter instead of the "this DependencyProperty" one that is used in C# extension methods (or else instead of static maybe they could use other keyword like type or typeof there, but I feel static is more appropriate).
Related discussion:
http://stackoverflow.com/questions/866921/static-extension-methods
http://stackoverflow.com/questions/249222/can-i-add-extension-methods-to-an-existing-static-class
Also see https://visualstudio.uservoice.com/forums/121579-visual-studio-2015/suggestions/2060313-c-support-static-extension-methods-like-f where somebody mentions "static extension properties" apart from "extension properties". Indeed it is natural that if static extension methods are to be allowed in the future, static extension properties should be added too (to extend a type with [attached] static properties)
You can vote for a related suggestion here:
George Birbilis @zoomicon 