选择日期时，带有 Eonasdan datepicker 的 Knockout bindingHandler 不会触发 dp.change 事件

Question

我正在使用 Knockout(ver 3.4.2)、moment(ver 2.29.1) 和 Eonasdan datepicker (ver 4.17.47) 插件来选择日期。

我的问题是当用户选择一个日期时 dp.change 事件没有被触发。它在打开日期选择器/小部件时触发，即用户单击日历图标。

结果是用户选择的第一个日期被忽略（事件在实际选择日期之前触发）并且只有当用户再次打开日期选择器并且事件触发时才会更新日期。

我一直在使用来自 eonasdans 安装页面的敲除绑定句柄示例： http://eonasdan.github.io/bootstrap-datetimepicker/Installing/

ko.bindingHandlers.datepicker = {
    init: function (element, valueAccessor, allBindingsAccessor) {
        //initialize datepicker with some optional options
        var options = allBindingsAccessor().datepickerOptions|| {};
        $(element).datetimepicker(options);

        //when a user changes the date, update the view model
        ko.utils.registerEventHandler(element, "dp.change", function (event) {
            var value = valueAccessor();
            if (ko.isObservable(value)) {
                if (event.date != null && !(event.date instanceof Date)) {
                    value(event.date.toDate());
                } else {
                    value(event.date);
                }
            }
        });

        ko.utils.domNodeDisposal.addDisposeCallback(element, function () {
            var picker = $(element).data("DateTimePicker");
            if (picker) {
                picker.destroy();
            }
        });
    },
    update: function (element, valueAccessor, allBindings, viewModel, bindingContext) {

        var picker = $(element).data("DateTimePicker");
        //when the view model is updated, update the widget
        if (picker) {
            var koDate = ko.utils.unwrapObservable(valueAccessor());

            //in case return from server datetime i am get in this form for example /Date(93989393)/ then fomat this
            //koDate = (typeof (koDate) !== 'object') ? new Date(parseFloat(koDate.replace(/[^0-9]/g, ''))) : koDate;

            picker.date(koDate);
        }
    }
};

我的淘汰赛视图是这样的：

var exportLicenserModel = function () {
        var self = this;
        self.Startdatum = ko.observable((new moment()).month(0).date(1));
}

HTML 是：

<div class='input-group js-date'>
  <input type="text" class="form-control" id="licenseStartDate" data-bind="datepicker: Startdatum, datepickerOptions: { locale: 'sv', format: 'YYYY-MM-DD', useCurrent: false }" />
  <span class="input-group-addon"><span class="glyphicon glyphicon-calendar"></span></span>
</div>

Answer 1

似乎工作得很好。我在dp.change 处理程序中添加了console.log 语句，还添加了一个文本绑定来显示Startdatum 的当前值。处理程序被调用并且值被更新。看看下面的sn-p：

ko.bindingHandlers.datepicker = {
  init: function(element, valueAccessor, allBindingsAccessor) {
    //initialize datepicker with some optional options
    var options = allBindingsAccessor().datepickerOptions || {};
    $(element).datetimepicker(options);

    //when a user changes the date, update the view model
    ko.utils.registerEventHandler(element, "dp.change", function(event) {
      var value = valueAccessor();
      if (ko.isObservable(value)) {
        if (event.date != null && !(event.date instanceof Date)) {
          value(event.date.toDate());
        } else {
          value(event.date);
        }
      }
      console.log(`Changed to ${value()}`);
    });

    ko.utils.domNodeDisposal.addDisposeCallback(element, function() {
      var picker = $(element).data("DateTimePicker");
      if (picker) {
        picker.destroy();
      }
    });
  },
  update: function(element, valueAccessor, allBindings, viewModel, bindingContext) {

    var picker = $(element).data("DateTimePicker");
    //when the view model is updated, update the widget
    if (picker) {
      var koDate = ko.utils.unwrapObservable(valueAccessor());

      //in case return from server datetime i am get in this form for example /Date(93989393)/ then fomat this
      //koDate = (typeof (koDate) !== 'object') ? new Date(parseFloat(koDate.replace(/[^0-9]/g, ''))) : koDate;

      picker.date(koDate);
    }
  }
};

var exportLicenserModel = function() {
  var self = this;
  self.Startdatum = ko.observable((new moment()).month(0).date(1));
}

ko.applyBindings(new exportLicenserModel());

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.5.3/js/bootstrap.min.js"></script>
<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.5.3/css/bootstrap.min.css" rel="stylesheet"/>
<link href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datetimepicker/4.17.47/css/bootstrap-datetimepicker.min.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.29.1/moment.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.2/knockout-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datetimepicker/4.17.47/js/bootstrap-datetimepicker.min.js"></script>

<div class='input-group js-date' style="position: relative">
  <input type="text" class="form-control" id="licenseStartDate" data-bind="datepicker: Startdatum, datepickerOptions: { locale: 'sv', format: 'YYYY-MM-DD', useCurrent: false }" />
  <span class="input-group-addon"><span class="glyphicon glyphicon-calendar"></span></span>
</div>
<p>StartDatum: <strong data-bind="text: Startdatum"></strong></p>

Answer 2

我找到了 dp.change 事件似乎没有触发的原因。

项目中有一个旧的和过时的 jQuery 类，它查找标记的日期选择器并激活它们，使它们绑定两次。

$('.js-date').datetimepicker({ locale: 'sv', format: 'YYYY-MM-DD', useCurrent: false });

删除后，一切都按预期工作。