【发布时间】：2020-05-15 07:25:49
【问题描述】：
// The counter example.
module Avalonia.Try2
module UI =
open Avalonia
open Avalonia.Media
open Avalonia.Controls
open Avalonia.Layout
open System
open System.Reactive
open System.Reactive.Linq
open System.Reactive.Disposables
open System.Reactive.Concurrency
open System.Reactive.Subjects
/// Lithe
let do' f c = f c; Disposable.Empty
let prop s v c = Observable.subscribe (s c) v
let event s f c = (s c : IEvent<_,_>).Subscribe(fun v -> f c v)
let control<'a when 'a :> Control> (c : unit -> 'a) l =
Observable.Create (fun (obs : IObserver<_>) ->
let c = c()
let d = Seq.map ((|>) c) l
obs.OnNext (c :> Control)
new CompositeDisposable(d) :> IDisposable
)
let children_template (l : Control IObservable seq) (c : Controls) =
l |> Seq.mapi (fun i v -> v.Subscribe (fun v -> if i < c.Count then c.[i] <- v else c.Add v))
|> fun x -> new CompositeDisposable(x) :> IDisposable
let children l (c : #Panel) = children_template l c.Children
let content v c = prop (fun (x : #ContentControl) v -> x.Content <- v) v c
let child v c = prop (fun (x : #Decorator) v -> x.Child <- v) v c
let window l = control Window l
let button l = control Button l
let stack_panel l = control StackPanel l
let dock_panel l = control DockPanel l
let slider l = control Slider l
let text_block l = control TextBlock l
let border l = control Border l
let separator l = control Separator l
let check_box l = control CheckBox l
/// Example
type Model = {
Count : int
Step : int
TimerOn : bool
}
type Msg =
| Increment
| Decrement
| Reset
| SetStep of int
| TimerToggled of bool
| TimedTick
let init = { Count = 0; Step = 1; TimerOn=false }
let pump = Subject.Synchronize(Subject(), Avalonia.Threading.AvaloniaScheduler.Instance)
let dispatch msg = pump.OnNext msg
let update =
pump.Scan(init, fun model msg ->
match msg with
| Increment -> { model with Count = model.Count + model.Step }
| Decrement -> { model with Count = model.Count - model.Step }
| Reset -> init
| SetStep n -> { model with Step = n }
| TimerToggled on -> { model with TimerOn = on }
| TimedTick -> if model.TimerOn then { model with Count = model.Count + model.Step } else model
)
.Publish(init)
let cmd_timer =
Observable.DistinctUntilChanged(update, fun x -> x.TimerOn)
.Select(fun model ->
if model.TimerOn then Observable.Interval(TimeSpan.FromSeconds(1.0)).Select(fun _ -> TimedTick)
else Observable.Empty()
)
.Switch()
let cmd() =
cmd_timer // If there was more than one command handler I'd merge them here.
.Subscribe(dispatch)
let view =
window [
do' (fun x -> x.Title <- "Counter Example"; x.SizeToContent <- SizeToContent.WidthAndHeight)
content <| border [
do' <| fun x -> x.BorderBrush <- Brushes.Red; x.BorderThickness <- Thickness 2.0
child <| stack_panel [
children [
text_block [
do' (fun l -> l.HorizontalAlignment <- HorizontalAlignment.Center; l.TextAlignment <- TextAlignment.Center)
prop (fun l v -> l.Text <- v) (update.Select(fun model -> sprintf "%d" model.Count))
]
button [
do' (fun b -> b.Content <- "Increment"; b.HorizontalAlignment <- HorizontalAlignment.Center)
event (fun b -> b.Click) (fun b arg -> dispatch Increment)
]
button [
do' (fun b -> b.Content <- "Decrement"; b.HorizontalAlignment <- HorizontalAlignment.Center)
event (fun b -> b.Click) (fun b arg -> dispatch Decrement)
]
stack_panel [
do' <| fun p ->
p.Orientation <- Orientation.Horizontal
p.HorizontalAlignment <- HorizontalAlignment.Center
p.Margin <- Thickness 20.0
children [
text_block [do' (fun l -> l.Text <- "Timer")]
check_box [
prop (fun c v -> c.IsChecked <- Nullable(v)) (update.Select(fun model -> model.TimerOn))
event (fun c -> c.Checked) (fun c v -> dispatch (TimerToggled true))
event (fun c -> c.Unchecked) (fun c v -> dispatch (TimerToggled false))
]
]
]
slider [
do' (fun s -> s.Minimum <- 0.0; s.Maximum <- 10.0; s.IsSnapToTickEnabled <- true)
prop (fun s v -> s.Value <- v) (update.Select(fun model -> model.Step |> float))
event (fun s -> s.PropertyChanged) (fun (c : Slider) (v : AvaloniaPropertyChangedEventArgs) ->
() // TODO
//if v.Property = Slider.ValueProperty then dispatch (SetStep (int v.NewValue))
)
]
text_block [
do' (fun l -> l.HorizontalAlignment <- HorizontalAlignment.Center)
prop (fun l v -> l.Text <- v) (update.Select(fun model -> sprintf "Step size: %d" model.Step))
]
button [
do' (fun b -> b.HorizontalAlignment <- HorizontalAlignment.Center; b.Content <- "Reset")
prop (fun b v -> b.IsEnabled <- v) (update.Select(fun model -> model <> init))
event (fun b -> b.Click) (fun b v -> dispatch Reset)
]
]
]
]
]
module Main =
open System
open Avalonia
open Avalonia.Controls
open Avalonia.Controls.ApplicationLifetimes
open Avalonia.Markup.Xaml.Styling
type App() =
inherit Application()
let d = new Reactive.Disposables.CompositeDisposable()
override x.Initialize() =
x.Styles.AddRange [
new StyleInclude(baseUri=null, Source = Uri("resm:Avalonia.Themes.Default.DefaultTheme.xaml?assembly=Avalonia.Themes.Default"))
new StyleInclude(baseUri=null, Source = Uri("resm:Avalonia.Themes.Default.Accents.BaseLight.xaml?assembly=Avalonia.Themes.Default"))
]
override x.OnFrameworkInitializationCompleted() =
match x.ApplicationLifetime with
| :? IClassicDesktopStyleApplicationLifetime as desktop ->
[
UI.view.Subscribe (fun v -> desktop.MainWindow <- v :?> Window)
UI.cmd()
UI.update.Connect()
] |> List.iter d.Add // TODO: Figure out how to dispose of this when App closes.
| _ -> ()
base.OnFrameworkInitializationCompleted()
interface IDisposable with member _.Dispose() = d.Dispose()
open Avalonia.Logging.Serilog
[<CompiledName "BuildAvaloniaApp">]
let buildAvaloniaApp () = AppBuilder.Configure<App>().UsePlatformDetect().LogToDebug()
let main argv = buildAvaloniaApp().StartWithClassicDesktopLifetime(argv)
Avalonia 的滑块的问题是它没有ValueChange 事件，所以我不知道在这里做什么：
event (fun s -> s.PropertyChanged) (fun (c : Slider) (v : AvaloniaPropertyChangedEventArgs) ->
() // TODO
//if v.Property = Slider.ValueProperty then dispatch (SetStep (int v.NewValue))
)
这是我要处理事件的地方，但我注释掉的行类型不正确。我应该在这里使用PropertyChanged，对吗？如果是这样，我如何检查哪些属性特别发生了变化？
【问题讨论】：
标签： f# avaloniaui