Ajax call inside validation rule

[A G]

   $("#myform").kendoValidator({

            rules:
                {
   
                    json_rule: function (input) {
                        var ret = true;
                        if (input.is("[id=pwd]")) {
                            $.ajax({
                                url: "api/HelperApi/Test" ,
                                type: 'Get',
                                data: { value: input.val() },
                                success: function (result) {
                                    ret = result === true;
                                }
                            });
                        }
                        return ret;
                    }

                },

            messages: {

                json_rule: "Json verified!",
    
       
            }
        });

I never see the message for some reason (I verified the server call, it does return true and false)

[Alexander Valchev]

Hello,

KendoUI validator is designed for performing a client-side validation. Remote validation is not supported at present.

The reason your code is not working is that Ajax request is asynchronous. json_rule function will return the result before success event handler of the Ajax request is executed.

Kind regards,
Alexander Valchev
the Telerik team

[A G]

Thanks Alexander

This works fine though when Ajax request is synchronous.

[Will]

Just for anyone else passing this way, there is a rather involved solution provided in detail here:

https://www.telerik.com/blogs/extending-the-kendo-ui-validator-with-custom-rules