CODEWITHSUNDEEP
winformsf#delegatesinvokedispatcher
MattP
MattP

Reputation: 71

F# Winforms Dispatcher BeginInvoke Delegate issue at runtime

I have tried to create an F# implementation of some C# code that uses Dispatcher.BeginInvoke to manipulate the UI from a different thread. However I'm struggling to get the code to work.

I've tried a few different implementations but I always seem to get a "Additional information: Illegal definition for runtime implemented delegate method." exception when calling the ToggleVisibility function.

Any input would be very gratefully received. Here is the code:-

open System
open System.Drawing
open System.Windows.Forms

type ToggleVisibiltyDelegate() = delegate of unit -> unit

type NotifyWindow() as form =
    inherit Form()
    let label1 = new Label()
    do form.InitializeForm

    member this.ToggleVisibility () =

        if (this.Visible) then
            this.BeginInvoke(new ToggleVisibiltyDelegate(fun () -> this.Hide()))
        else
            this.BeginInvoke(new ToggleVisibiltyDelegate(fun () -> this.Show()))

Upvotes: 4

Views: 189

Answers (1)

MattP
MattP

Reputation: 71

Solved! How frustrating to have spent so much time trying various methods when all I had to do was delete two parentheses, turning

type ToggleVisibiltyDelegate() = delegate of unit -> unit

into

type ToggleVisibiltyDelegate = delegate of unit -> unit

Upvotes: 3

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