Change an Observable from Uno


Does anyone have any examples on changing an Observable from Uno code? I’ve tried several things, but I doesn’t change in JS.

  • Bjørn-Olav


If you have a Fuse.Scripting.Object which is the Observable, you should be able to do

obj.CallMethod("setValueExclusive", value);


I would like to have a UX like this:

<MyAwesomeElement Property="{js_prop}" />

And then change that from Uno. I’ve tried this:

foreach (var b in Behaviors) {
    if (b is Fuse.Reactive.DataBinding<float2>) {
        var db = b as Fuse.Reactive.DataBinding<float2>;

This is my other try, using StyleProperty:

    public static readonly StyleProperty<BindPanel, float2> SizeProperty
        = new StyleProperty<BindPanel, float2>(float2(0,0), null, SetSize, GetSize);

    float2 _size = float2(0,0);
    public float Size
        get { return _size; }
        set { 
            SizeProperty.Set(this, value);

    static float2 GetSize(BindPanel p)
        return p._size;

    static void SetSize(BindPanel p, float2 size)
        p._size = size;

    public void SetSize(float2 size, object origin)
        _size = size;

But still no luck.

What you are trying to do is sort of an antipattern. JS feeds the UI with values, not the other way around. The only exception is two-way data binding-enabled properties like TextInput.Value, but I don’t think that covers this case either.

Can you instead try to describe what you are ultimately trying to do here? What is the use case?

I am trying to do something like this:

        var Observable = require('FuseJS/Observable');

        var size = Observable([0,0]);
        var imageurl = Observable('');
        function setUrl () {
            imageurl.value = '; + size.value.X + '&h=' + size.value.Y;

        module.exports = {
            size: size,
            imageurl: imageurl
    <Panel Size="{size}">
        <Image Url="{imageurl}" />