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ObservableObject

The ObservableObject type implements the INotifyPropertyChanged interface used in WPF and Silverlight to notify on changes to properties that are bound to a control. Specify property names type safely using F# Quotations, i.e. <@ this.PropertyName @> when invoking the NotifyPropertyChanged method. If you are following the MVVM pattern then your View Model class can inherit from the ObservableObject type.

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#if INTERACTIVE
#r "PresentationCore.dll"
#r "PresentationFramework.dll"
#r "WindowsBase.dll"
#endif

open System.ComponentModel
open Microsoft.FSharp.Quotations.Patterns

type ObservableObject () =
    let propertyChanged = DelegateEvent<PropertyChangedEventHandler>()
    let getPropertyName = function 
        | PropertyGet(_,pi,_) -> pi.Name 
        | _ -> invalidOp "Expecting property getter expression"
    interface INotifyPropertyChanged with
        [<CLIEvent>]
        member this.PropertyChanged = propertyChanged.Publish
    member this.NotifyPropertyChanged propertyName = 
        propertyChanged.Trigger [|this; PropertyChangedEventArgs propertyName|]
    member this.NotifyPropertyChanged quotation = 
        quotation |> getPropertyName |> this.NotifyPropertyChanged

type MessageViewModel () =
    inherit ObservableObject()
    let mutable text = ""
    member this.Message
        with get () = text
        and set value = 
            text <- value
            this.NotifyPropertyChanged <@ this.Message @>

open System.Windows
open System.Windows.Controls
open System.Windows.Markup

let xaml = 
    @"<Window xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'
              xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'>
       <TextBlock Text='{Binding Message}'/>
      </Window>"
let view = XamlReader.Parse(xaml) :?> Window
do  view.DataContext <- MessageViewModel(Message="Hello World")
#if INTERACTIVE
do  view.Show() |> ignore
#else
[<System.STAThread>]
do  (Application()).Run(view) |> ignore
#endif

namespace System

namespace System.ComponentModel

namespace Microsoft

namespace Microsoft.FSharp

namespace Microsoft.FSharp.Quotations

module Patterns

from Microsoft.FSharp.Quotations

Multiple items
type ObservableObject =
  interface INotifyPropertyChanged
  new : unit -> ObservableObject
  member NotifyPropertyChanged : propertyName:string -> unit
  member NotifyPropertyChanged : quotation:Expr -> unit

Full name: Script.ObservableObject

--------------------
new : unit -> ObservableObject

val propertyChanged : DelegateEvent<PropertyChangedEventHandler>

Multiple items
type DelegateEvent<'Delegate (requires 'Delegate :> Delegate)> =
  new : unit -> DelegateEvent<'Delegate>
  member Trigger : args:obj [] -> unit
  member Publish : IDelegateEvent<'Delegate>

Full name: Microsoft.FSharp.Control.DelegateEvent<_>

--------------------
new : unit -> DelegateEvent<'Delegate>

type PropertyChangedEventHandler =
delegate of obj * PropertyChangedEventArgs -> unit

Full name: System.ComponentModel.PropertyChangedEventHandler

val getPropertyName : (Quotations.Expr -> string)

active recognizer PropertyGet: Quotations.Expr -> (Quotations.Expr option * System.Reflection.PropertyInfo * Quotations.Expr list) option

Full name: Microsoft.FSharp.Quotations.Patterns.( |PropertyGet|_| )

val pi : System.Reflection.PropertyInfo

property System.Reflection.MemberInfo.Name: string

val invalidOp : message:string -> 'T

Full name: Microsoft.FSharp.Core.Operators.invalidOp

type INotifyPropertyChanged =
event PropertyChanged : PropertyChangedEventHandler

Full name: System.ComponentModel.INotifyPropertyChanged

Multiple items
type CLIEventAttribute =
inherit Attribute
new : unit -> CLIEventAttribute

Full name: Microsoft.FSharp.Core.CLIEventAttribute

--------------------
new : unit -> CLIEventAttribute

val this : ObservableObject

override ObservableObject.PropertyChanged : IDelegateEvent<PropertyChangedEventHandler>

Full name: Script.ObservableObject.PropertyChanged

property DelegateEvent.Publish: IDelegateEvent<PropertyChangedEventHandler>

member ObservableObject.NotifyPropertyChanged : propertyName:string -> unit

Full name: Script.ObservableObject.NotifyPropertyChanged

val propertyName : string

member DelegateEvent.Trigger : args:obj [] -> unit

Multiple items
type PropertyChangedEventArgs =
  inherit EventArgs
  new : propertyName:string -> PropertyChangedEventArgs
  member PropertyName : string

Full name: System.ComponentModel.PropertyChangedEventArgs

--------------------
PropertyChangedEventArgs(propertyName: string) : unit

member ObservableObject.NotifyPropertyChanged : quotation:Quotations.Expr -> unit

Full name: Script.ObservableObject.NotifyPropertyChanged

val quotation : Quotations.Expr

member ObservableObject.NotifyPropertyChanged : propertyName:string -> unit
member ObservableObject.NotifyPropertyChanged : quotation:Quotations.Expr -> unit

Multiple items
type MessageViewModel =
  inherit ObservableObject
  new : unit -> MessageViewModel
  member Message : string
  member Message : string with set

Full name: Script.MessageViewModel

--------------------
new : unit -> MessageViewModel

val mutable text : string

val this : MessageViewModel

member MessageViewModel.Message : string with set

Full name: Script.MessageViewModel.Message

val set : elements:seq<'T> -> Set<'T> (requires comparison)

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.set

val value : string

property MessageViewModel.Message: string

namespace System.Windows

namespace System.Windows.Controls

namespace System.Windows.Markup

val xaml : string

Full name: Script.xaml

val view : Window

Full name: Script.view

Multiple items
type XamlReader =
  new : unit -> XamlReader
  member CancelAsync : unit -> unit
  member LoadAsync : stream:Stream -> obj + 2 overloads
  event LoadCompleted : AsyncCompletedEventHandler
  static member GetWpfSchemaContext : unit -> XamlSchemaContext
  static member Load : stream:Stream -> obj + 3 overloads
  static member Parse : xamlText:string -> obj + 1 overload

Full name: System.Windows.Markup.XamlReader

--------------------
XamlReader() : unit

XamlReader.Parse(xamlText: string) : obj
XamlReader.Parse(xamlText: string, parserContext: ParserContext) : obj

Multiple items
type Window =
  inherit ContentControl
  new : unit -> Window
  member Activate : unit -> bool
  member AllowsTransparency : bool with get, set
  member Close : unit -> unit
  member DialogResult : Nullable<bool> with get, set
  member DragMove : unit -> unit
  member Hide : unit -> unit
  member Icon : ImageSource with get, set
  member IsActive : bool
  member Left : float with get, set
  ...

Full name: System.Windows.Window

--------------------
Window() : unit

property FrameworkElement.DataContext: obj

Multiple items
type STAThreadAttribute =
inherit Attribute
new : unit -> STAThreadAttribute

Full name: System.STAThreadAttribute

--------------------
System.STAThreadAttribute() : unit

Multiple items
active recognizer Application: Quotations.Expr -> (Quotations.Expr * Quotations.Expr) option

Full name: Microsoft.FSharp.Quotations.Patterns.( |Application|_| )

--------------------
type Application =
  inherit DispatcherObject
  new : unit -> Application
  member FindResource : resourceKey:obj -> obj
  member MainWindow : Window with get, set
  member Properties : IDictionary
  member Resources : ResourceDictionary with get, set
  member Run : unit -> int + 1 overload
  member Shutdown : unit -> unit + 1 overload
  member ShutdownMode : ShutdownMode with get, set
  member StartupUri : Uri with get, set
  member TryFindResource : resourceKey:obj -> obj
  ...

Full name: System.Windows.Application

--------------------
Application() : unit

val ignore : value:'T -> unit

Full name: Microsoft.FSharp.Core.Operators.ignore

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More information

Link:	http://fssnip.net/2x
Posted:	13 years ago
Author:	Phillip Trelford
Tags:	wpf , silverlight , mvvm