我真的很喜欢Eric Barnard's knockout validation lib与 observable 集成，允许分组，并提供自定义验证器可插入性(包括即时验证器)。有几个地方可以使用户体验更加灵活/友好，但总体而言，它的文档相当齐全... except, imo, when it comes to async validators .

在进行搜索和 landing on this 之前，我今天与此搏斗了几个小时.我想我和原作者有同样的问题/问题，但我同意并不清楚 duxa 到底在要求什么。我想引起更多关注，所以我也在这里问。

function MyViewModel() {
    var self = this;
    self.nestedModel1.prop1 = ko.observable().extend({
        required: { message: 'Model1 Prop1 is required.' },
        maxLength: {
            params: 140,
            message: '{0} characters max please.'
        }
    });
    self.nestedModel2.prop2 = ko.observable().extend({
        required: { message: 'Model2 Prop2 is required' },
        validation: {
            async: true,
            validator: function(val, opts, callback) {
                $.ajax({                                  // BREAKPOINT #1
                    url: '/validate-remote',
                    type: 'POST',
                    data: { ...some data... }
                })
                .success(function(response) {
                    if (response == true) callback(true); // BREAKPOINT #2
                    else callback(false);
                });
            },
            message: 'Sorry, server says no :('
        }
    });
}

ko.validation.group(self.nestedModel1);
ko.validation.group(self.nestedModel2);

ko.validation.validateObservable = function(observable) {
    // set up variables & check for conditions (omitted for brevity)

    // loop over validators attached to the observable
    for (; i < len; i++) {
        if (rule['async'] || ctx['async']) {
            //run async validation
            validateAsync();
        } else {
            //run normal sync validation
            if (!validateSync(observable, rule, ctx)) {
                return false; //break out of the loop
            }
        }
    }

    //finally if we got this far, make the observable valid again!
    observable.error = null;
    observable.__valid__(true);
    return true;
}

//the true holder of whether the observable is valid or not
observable.__valid__ = ko.observable(true);

function validateAsync(observable, rule, ctx) {
    observable.isValidating(true);

    var callBack = function (valObj) {
        var isValid = false,
            msg = '';

        if (!observable.__valid__()) {
            // omitted for brevity, __valid__ is true in this scneario
        }

        //we were handed back a complex object
        if (valObj['message']) {
            isValid = valObj.isValid;
            msg = valObj.message;
        } else {
            isValid = valObj;
        }

        if (!isValid) {
            //not valid, so format the error message...
            observable.error = ko.validation.formatMessage(...);
            observable.__valid__(isValid);
        }

        // tell it that we're done
        observable.isValidating(false);
    };

    //fire the validator and hand it the callback
    rule.validator(observable(), ctx.params || true, callBack);
}

最佳答案

所以我问的问题实际上与如何在 ko.validation 中使用异步验证器有关。我从我的经验中学到了两个重要的收获:

var viewModel = {
    var self = this;
    self.prop1 = ko.observable().extend({validateProp1Async: self});
    self.prop2 = ko.observable().extend({validateProp2Async: self});
    self.propN = ko.observable();
    self.isValidating = ko.computed(function() {
        return self.prop1.isValidating() || self.prop2.isValidating();
    });
    self.saveData = function(arg1, arg2, argN) {

        if (self.isValidating()) {
            setTimeout(function() {
                self.saveData(arg1, arg2, argN);
            }, 50);
            return false;
        }

        if (!self.isValid()) {
            self.errors.showAllMessages();
            return false;
        }

        // data is now trusted to be valid
        $.post('/something', 'data', function() { doWhatever() });
    }
};

var validateProp1Async = {
    async: true,
    message: 'you suck because your input was wrong fix it or else',
    validator: function(val, otherVal, callback) {
        // val will be the value of the viewmodel's prop1() observable
        // otherVal will be the viewmodel itself, since that was passed in
        //     via the .extend call
        // callback is what you need to tell ko.validation about the result
        $.ajax({
            url: '/path/to/validation/endpoint/on/server',
            type: 'POST', // or whatever http method the server endpoint needs
            data: { prop1: val, otherProp: otherVal.propN() } // args to send server
        })
        .done(function(response, statusText, xhr) {
            callback(true); // tell ko.validation that this value is valid
        })
        .fail(function(xhr, statusText, errorThrown) {
            callback(false); // tell ko.validation that his value is NOT valid
            // the above will use the default message. You can pass in a custom
            // validation message like so:
            // callback({ isValid: false, message: xhr.responseText });
        });
    }
};

关于javascript - knockout 验证异步验证器 : Is this a bug or am I doing something wrong?，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12721951/