Async.StartWithContinuations<'T> Method (F#)
Visual Studio 2010
Runs an asynchronous computation, starting immediately on the current operating system thread. Call one of the three continuations when the operation completes.
Namespace/Module Path: Microsoft.FSharp.Control
Assembly: FSharp.Core (in FSharp.Core.dll)
// Signature:
static member StartWithContinuations : Async<'T> * ('T -> unit) * (exn -> unit) * (OperationCanceledException -> unit) * ?CancellationToken -> unit
// Usage:
Async.StartWithContinuations (computation, continuation, exceptionContinuation, cancellationContinuation)
Async.StartWithContinuations (computation, continuation, exceptionContinuation, cancellationContinuation, cancellationToken = cancellationToken)
The following code example illustrates the use of Async.StartWithContinuations.
open System.Windows.Forms let bufferData = Array.zeroCreate<byte> 100000000 let async1 (label:System.Windows.Forms.Label) filename = Async.StartWithContinuations( async { label.Text <- "Operation started." use outputFile = System.IO.File.Create(filename) do! outputFile.AsyncWrite(bufferData) }, (fun _ -> label.Text <- "Operation completed."), (fun _ -> label.Text <- "Operation failed."), (fun _ -> label.Text <- "Operation canceled.")) let form = new Form(Text = "Test Form") let button1 = new Button(Text = "Start") let button2 = new Button(Text = "Start Invalid", Top = button1.Height + 10) let button3 = new Button(Text = "Cancel", Top = 2 * button1.Height + 20) let label1 = new Label(Text = "", Width = 200, Top = 3 * button1.Height + 30) form.Controls.AddRange [| button1; button2; button3; label1 |] button1.Click.Add(fun args -> async1 label1 "longoutput.dat") // Try an invalid filename to test the error case. button2.Click.Add(fun args -> async1 label1 "|invalid.dat") button3.Click.Add(fun args -> Async.CancelDefaultToken()) Application.Run(form)
