Define an abstract class that inherits an infterface, but does not implement it

Question

incorporating leppies feedback it compiles - but IMO some drawbacks I want each sub class to be forced by the compiler to define their own Uri property. Code as it is now:

Answer 1

Here is a way to do it:

type IUriProvider =  
    abstract member UriString: string
    abstract member Uri : System.Uri

[]  
type UriUserControl() as this =  
    inherit System.Windows.Controls.UserControl() 
    abstract member Uri : System.Uri
    abstract member UriString : string
    interface IUriProvider with 
        member x.Uri = this.Uri
        member x.UriString = this.UriString

Note that you have to provide an implementation of the interface (since all interface implementations in F# are explicit), but this can just refer back to abstract members in the class. Then you can subclass thusly:

type ConcreteUriUserControl() =
    inherit UriUserControl()
    override this.Uri = null
    override this.UriString = "foo"