Hi,

I dont think that you could simply use Deferred object in isValid method.

You could try to add _ValidationMixin to your widget.

Then in your ajax request in success set state to Ok, and in fail set state to "Error":

isValid: function() {
    var value = this.myProperty.value;

var self = this;    

$.ajax({
        type: 'POST',
        url: '/api/myproperty/validate/',
        data: { Value: value },
        dataType: 'json',
        success: function (data) {
            self.set("state", "ok");
        },
        fail: function() {
            self.set("state", "Error");
        },
        async: false
    });

return true;
}

But you should also implement the server validation for model,  (for example implementing IValidate interface).

Hi Grzegorz,

Thanks for help!

The code you sent me always returns true, and epi editor is prompted to publish changes.

I made a small hack using data attribute which seems to work fine.

postCreate: function() {
   ...
   var self = this;
   
   this.myproperty.validator = function() {
      return self.myproperty.attr('data-isvalid') === 'true';
   };
   
   on(this.myProperty, "change", function(e) {
      xhr("/api/myproperty/validate/", {
         data: { Value: e },
         method: "POST",
         handleAs: "json",
         sync: true
    }).then(function(data) {
         if (data.IsValid) {
            self.myProperty.attr('data-isvalid', 'true');
         } else {
            self.myProperty.attr('data-isvalid', 'false');
         }
       self._set('value', data.Url);
       self.onChange(data.Url);
       });
    });
},
isValid: function() {
    var isValid = this.myproperty.attr('data-isvalid') === 'true';
    this.myproperty.validate();

    return isValid;
}