小编Rei*_*ica的帖子

我需要能够在F#interactive中创建一个新的AppDomain,以便托管多个WPF应用程序.我在编译的F#应用程序中获得必要的功能没有任何问题,但由于某种原因使其在F#interactive中工作似乎不可能.

这是最简单的案例: -

#r "PresentationCore.dll"
#r "PresentationFramework.dll"
#r "System.Xaml.dll"
#r "WindowsBase.dll"

open System    
open System.Threading
open System.Windows

type myClass() = 
    let domain = AppDomain.CreateDomain("another domain")

    //this function starts a WPF app
    let funct() =                
        let WPFStart() =
            let app = Application()
            let win = Window()            
            app.Run(win) |> ignore
        let thread = Thread WPFStart
        thread.IsBackground <- true
        thread.SetApartmentState ApartmentState.STA
        thread.Start()

    do CrossAppDomainDelegate(funct) |> domain.DoCallBack

myClass();;

我总是回过头来做些什么

System.Runtime.Serialization.SerializationException: Type is not resolved 
for member 'FSI_0002+-ctor@24,FSI-ASSEMBLY, Version=0.0.0.0, 
Culture=neutral, PublicKeyToken=null'.
at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
at …

我想在TextBox中按"Enter"时开始动画.我没有找到合适的事件,所以我做了以下事情

XAML

    <Window.DataContext>
        <local:MainViewModel/>
    </Window.DataContext>
    <Window.Resources>
        <Storyboard x:Key="testAnimation">
            <BooleanAnimationUsingKeyFrames
                                    FillBehavior="HoldEnd"
                                    Storyboard.TargetName="txtB"
                                    Storyboard.TargetProperty="IsEnabled">
                <DiscreteBooleanKeyFrame KeyTime="00:00:00" 
                                                     Value="False" />
            </BooleanAnimationUsingKeyFrames>
            <DoubleAnimation 
                                    Storyboard.TargetName="rtbl"
                                    Storyboard.TargetProperty="Opacity" 
                                    From="0"
                                    To="1"  
                                    Duration="0:0:2"
                                    AutoReverse="True">
            </DoubleAnimation>
            <BooleanAnimationUsingKeyFrames
                                    FillBehavior="HoldEnd"
                                    Storyboard.TargetName="txtB"
                                    Storyboard.TargetProperty="IsEnabled"
                                    BeginTime="0:0:4"
                                    >
                <DiscreteBooleanKeyFrame KeyTime="00:00:00" 
                                                     Value="True" />
            </BooleanAnimationUsingKeyFrames>
        </Storyboard>
    </Window.Resources>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
        </Grid.RowDefinitions>
        <TextBlock Grid.Row="0" Name="rtbl" Opacity="0" HorizontalAlignment="Center" Margin="10" FontSize="30" Text="{Binding Text}"></TextBlock>
        <TextBox Grid.Row="1" Name="txtB"  IsEnabled="True"  HorizontalAlignment="Center" 
                 Margin="10" FontSize="30" Text="{Binding Input, UpdateSourceTrigger=PropertyChanged}" MinWidth="150"
                 >
            <TextBox.InputBindings>
                <KeyBinding Command="{Binding NextCommand}" Key="Enter"
                    CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}">
                </KeyBinding>
            </TextBox.InputBindings>
        </TextBox>
    </Grid> …

在我的xaml我有一个按钮和一个TextBlock

<TextBlock Text="{Binding AText}" FontSize="20"/>
<Button Content="Click" Command="{Binding MyCommand}" Grid.Row="1"/>

在我的ViewModel中,我有以下代码

let aText = self.Factory.Backing(<@ self.AText @>, "Initial Text")
let asyncTask x = async {
    self.AText <- "Loading"
    do! Async.Sleep(5000)
    self.AText <- "Loaded"
} 

member self.AText with get() = aText.Value and set(v) = aText.Value <- v    
member self.MyCommand = self.Factory.CommandAsyncChecked(asyncTask, fun _ -> true)

当我单击按钮时,它会被禁用并保持不变,直到它完成asyncTask.我认为设置canExecute为true将改变行为,但事实并非如此!

如何控制按钮的行为？

无法理解这种行为的原因:

let example count = 
    let arr = Array.create 2 (Array.zeroCreate count)
    for i in [0..count - 1] do
        arr.[0].[i] <- 1
        arr.[1].[i] <- 2
    arr

example 2 |> Array.iter(printfn "%A")

打印:

[|2; 2|]
[|2; 2|]

https://dotnetfiddle.net/borMmO

如果我更换:

let arr = Array.create 2 (Array.zeroCreate count)

至:

let arr = Array.init 2 (fun _ -> Array.zeroCreate count)

一切都会按预期工作:

let example count = 
    let arr = Array.init 2 (fun _ -> Array.zeroCreate count)
    for i in [0..count - 1] do
        arr.[0].[i] <- …

有人可以告诉我如何在列表包含特定号码时过滤掉列表.例如,如果子列表包含2,那么我想要第三个值.

let p = [ [0;2;1]; [7;2;5]; [8;2; 10]; [44; 33; 9]]
//Filtered List: [1;5;10]
let q = p |> List.filter(fun((x,y):int List)  (List.item 2 x) = 1,  (List.item 3 y))

上面是我的代码到目前为止.我知道它的错误,但似乎无法在代码中弄明白.

对不起,如果这看起来像一个愚蠢的问题,我仍然想弄清楚F#是如何做的

所以,说我建立了以下记录:

type person = 
{ fName: string;
  lName: string;
  age: int;
  weight: int; }

然后我创建一些人来填充记录

let joe   = {fName = "JOE";   lName = "QUAIL"; age = 34; weight = 133}
let jason = {fName = "JASON"; lName = "QUAIL"; age = 34; weight = 166}
let jerry = {fName = "JERRY"; lName = "PAIL";  age = 26; weight = 199}

因此,我想要做的是至少需要两个或三个参数(比如age,和lName),我想通过搜索person记录所有谁满足输入参数的人age,并lName与目标是将它们添加到列表中.所以在这个例子中,我想通过记录搜索姓氏"QUAIL"和34岁,这将得到我和乔和杰森

在F#中,我认为模式匹配是可行的方法,但我不知道如何实现模式匹配结构.

我的想法是使用这样的结构:

let myPeeps =
 List.filter (function
  | …

我想在Suave中使用非拉丁符号,例如西里尔字母,但得到奇怪的结果

MCVE

open Suave
open Suave.Filters
open Suave.Operators
open Suave.Successful

let app =
    choose [
        GET >=>  OK "??????, ???!" 
    ]

startWebServer defaultConfig app

结果

所以,Q是 - 如何解决它？

在本教程INotifyPropertyChanged中模式-不是在视图模型.

这是正确和可接受的吗？什么是标准？