PropertyChanged.fs

namespace MvvmCrossTests.Core.FSharp
 
open System
open  Cirrious.MvvmCross.ViewModels
 
open Microsoft.FSharp.Quotations
open Microsoft.FSharp.Quotations.Patterns
 
 
// One way of accessing the name of an expression that can be passed to the RaisePropertyChanged is
// to provide a ToString style method
// Unfortunately F# won't let me add an extension method to the Expr<string> as it's a generic type and currently
// this isn't supported.
module test =
    let tostring (expr : Expr<string>) = 
        match expr with
        | PropertyGet(a, b, list) -> b.Name
        | _ -> ""
 
// New base class to encapsulate the RaisePropertyChanged from the expression
type MvxViewModelBase1() =
   inherit MvxViewModel()
 
   // Unfortunately there is no protected in F#
   member self.RaisePropertyChanged(expr : Expr<string>) =
        match expr with
        | PropertyGet(a, b, list) -> self.RaisePropertyChanged(b.Name)
        | _ -> ()
 
type Class1() = 
    inherit MvxViewModelBase1()
 
    let mutable url = ""
    let mutable other = ""
 
    member self.Url
        with get() = url
        and set(value) =
            url <- value
            self.RaisePropertyChanged( <@ self.Url @> |> test.tostring )
 
    member self.Other
        with get() = other
        and set(value) =
            other <- value
            self.RaisePropertyChanged( <@ self.Other @> )