wpff#gjallarhorn

A correct way to handle multiple command (from buttons) with Gjallarhorn

There are a couple of buttons on the window and I try to find good approach to handle commands.

For example:

I have to perform some actions:

type Action = 
    |Show
    |Open
    |Input
    |Change
    |Statistic

translating this to the xaml will be:

<Button Command="{Binding ShowCommand}" />
<Button Command="{Binding OpenCommand}" />
<Button Command="{Binding InputCommand}" />
<Button Command="{Binding ChangeCommand}" />
<Button Command="{Binding StatisticCommand}" />

a bit playing with library I found two ways to do it without annoying verbose

1. Use Observable.merge

Binding.createMessage "StatisticCommand" Statistic source
|> Observable.merge (Binding.createMessage "InputCommand" Input source)
//|> Observable.merge ... and so on
|> Observable.subscribe (performAction model.Value)
|> source.AddDisposable

2. Create generalize message 

type GeneralMessage = 
    |Perform of Action
    |Update of Message

and raise up the action message to the high level

let mainComponent source (model : ISignal<Info>) = 

    let info = Binding.componentToView source "Info" infoComponent model
    //...

    let stat = Binding.createMessage "StatCommand" (Perform Statistic) source
    let input = Binding.createMessage "InputCommand" (Perform Input) source
    //let ...

    [info; stat; input; ...]

let appComponent = 
    let model = initInfo
    let update message model = 
        match message with
        |Update message -> 
            match message with
            |...
        |Perform action -> 
            performAction model action
            model

    Framework.basicApplication model update mainComponent

(Well, I like first option, cause this actions don't change the model)

Is it correct way (the first, obvious) to do these things or library contains more fitting function ?

P.S. I looked for Observable.concat [info; stat; input; ...] but wasn't catch lucky.

Solution

  • So either option is fine here. I think the appropriate approach depends on how this is used, and what data is required: