Back to Questions
2.2k
views2
comments
Best way to create a status indicator
websharperhow toq&aqnaquestion

I have some code that takes some time to run on the client side. What is the best way to provide feedback to the user to wait? When I create a Var.View, modifying the value does not update while the computation is ongoing.

.

An example: if your code is like

1
2
3

varIsRunning.Value <- true
runComputation()
varIsRunning.Value <- false

rewrite it like this:

1
2
3
4
5

varIsRunning.Value <- true
async {
    do! runComputation()
    varIsRunning.Value <- false
} |> Async.Start

This will also need that your code inside runComputation is also wrapped in an async.

By on 2/2/2018 6:40 AM ()

Hi! Do you have your long computation as an async expression? (I am assuming you use F#. If you are interested in C#, please tell and I will give advice for that too.)

JavaScript is single-threaded, so WebSharper is using a round-robin scheduler for running asyncs, regularly yielding so that other JS event handlers can run too. Even if you have your outer computation function as async, if it is calling any function that takes long to execute (for example has large loops), that part will be blocking (preventing any UI updates, including WebSharper.UI reactive logic). So all potentionally long-running functions should be written as an async. Having loops inside an async expression, F# automatically breaks it down so it is yielding control after every iteration.

By on 2/2/2018 6:14 AM ()

    Topic tags

    IntelliFactory Offices Copyright (c) 2011-2012 IntelliFactory. All rights reserved.
    Home | Products | Consulting | Trainings | Blogs | Jobs | Contact Us | Terms of Use | Privacy Policy | Cookie Policy     		Built with WebSharper