F#中的DialogResult [英] DialogResult in F#

问题描述

尝试从MVVM应用程序的窗口中检索DialogResult时，我偶然发现了上一个问题.实施建议的更改后，示例如下所示:

Trying to retrieve a DialogResult from a window in a MVVM app, I stumbled on this previous question. After implementing the suggested changes, the sample looks like:

type DialogCloser() =

    static let DialogResultProperty =
        DependencyProperty.RegisterAttached("DialogResult", typeof<bool>, typeof<DialogCloser>, new PropertyMetadata(DialogResultChanged))

    static member GetDialogResult (a:DependencyObject) =
        a.GetValue(DialogResultProperty) :?> bool

    static member SetDialogResult (a:DependencyObject) (value:string) = 
        a.SetValue(DialogResultProperty, value)

    member this.DialogResultChanged (a:DependencyObject) (e:DependencyPropertyChangedEventArgs) =
        let window = a :?> Window
        match window with
        | null -> failwith "Not a Window"
        | _ -> window.DialogResult <- System.Nullable (e.NewValue :?> bool)

现在在声明之前使用DialogResultChanged，这当然不会在F#中进行计算.

Now DialogResultChanged is used before it is declared, which of course doesn't compute in F#.

我似乎找不到可行的解决方案，将不胜感激.

I can't seem to find a working solution, any help would be appreciated .

推荐答案

我不是WPF专家，但是在

I'm not a WPF expert, but in this related C# solution, the DialogResultsChanged method is static. If you define the method as static in F# too, you should be able to reference it before it is declared (using the full name DialogCloser.DialogResultsChanged), so something like the following should do the trick:

type DialogCloser() =

    static let DialogResultProperty =
        DependencyProperty.RegisterAttached
            ( "DialogResult", typeof<bool>, typeof<DialogCloser>, 
              new PropertyMetadata(DialogCloser.DialogResultChanged))

    static member GetDialogResult (a:DependencyObject) =
        a.GetValue(DialogResultProperty) :?> bool

    static member SetDialogResult (a:DependencyObject) (value:string) = 
        a.SetValue(DialogResultProperty, value)

    static member DialogResultChanged 
            (a:DependencyObject) (e:DependencyPropertyChangedEventArgs) =
        let window = a :?> Window
        match window with
        | null -> failwith "Not a Window"
        | _ -> window.DialogResult <- System.Nullable (e.NewValue :?> bool)

这篇关于F#中的DialogResult的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！