我創建了Vue公司的自定義選擇2輸入元素2.的Vue 2自定義選擇2:爲什麼不@change工作時@input工作
我的問題是:爲什麼是
<select2 v-model="vacancy.staff_member_id" @input="update(vacancy)"></select2>
工作,但
<select2 v-model="vacancy.staff_member_id" @change="update(vacancy)"></select2>
不是嗎?
由於Vue的正常<input>
元素都有@change
處理程序,這將是很好,如果我的自定義選擇2輸入具有相同的。
我的自定義元素上的一些信息:
該元素的目的是不呈現所有<option>
元素,但只有那些需要的,因爲我們有內部的一個頁面上的許多選擇2輸入和多種選擇一個select2輸入,導致頁面加載變慢。
該解決方案使其更快。
Vue.component('select2', {
props: ['options', 'value', 'placeholder', 'config', 'disabled'],
template: '<select><slot></slot></select>',
data: function() {
return {
newValue: null
}
},
mounted: function() {
var vm = this;
$.fn.select2.amd.require([
'select2/data/array',
'select2/utils'
], function (ArrayData, Utils) {
function CustomData ($element, options) {
CustomData.__super__.constructor.call(this, $element, options);
}
Utils.Extend(CustomData, ArrayData);
CustomData.prototype.query = function (params, callback) {
if (params.term && params.term !== '') {
// search for term
var results;
var termLC = params.term.toLowerCase();
var length = termLC.length;
if (length < 3) {
// if only one or two characters, search for words in string that start with it
// the string starts with the term, or the term is used directly after a space
results = _.filter(vm.options, function(option){
return option.text.substr(0,length).toLowerCase() === termLC ||
_.includes(option.text.toLowerCase(), ' '+termLC.substr(0,2));
});
}
if (length > 2 || results.length < 2) {
// if more than two characters, or the previous search give less then 2 results
// look anywhere in the texts
results = _.filter(vm.options, function(option){
return _.includes(option.text.toLowerCase(), termLC);
});
}
callback({results: results});
} else {
callback({results: vm.options}); // no search input -> return all options to scroll through
}
};
var config = {
// dataAdapter for displaying all options when opening the input
// and for filtering when the user starts typing
dataAdapter: CustomData,
// only the selected value, needed for un-opened display
// we are not using all options because that might become slow if we have many select2 inputs
data:_.filter(vm.options, function(option){return option.id === parseInt(vm.value);}),
placeholder:vm.placeholder
};
for (var attr in vm.config) {
config[attr] = vm.config[attr];
}
if (vm.disabled) {
config.disabled = vm.disabled;
}
if (vm.placeholder && vm.placeholder !== '') {
$(vm.$el).append('<option></option>');
}
$(vm.$el)
// init select2
.select2(config)
.val(vm.value)
.trigger('change')
// prevent dropdown to open when clicking the unselect-cross
.on("select2:unselecting", function (e) {
$(this).val('').trigger('change');
e.preventDefault();
})
// emit event on change.
.on('change', function() {
var newValue = $(this).val();
if (newValue !== null) {
Vue.nextTick(function(){
vm.$emit('input', newValue);
});
}
})
});
},
watch: {
value: function (value, value2) {
if (value === null) return;
var isChanged = false;
if (_.isArray(value)) {
if (value.length !== value2.length) {
isChanged = true;
} else {
for (var i=0; i<value.length; i++) {
if (value[i] !== value2[i]) {
isChanged = true;
}
}
}
} else {
if (value !== value2) {
isChanged = true;
}
}
if (isChanged) {
var selectOptions = $(this.$el).find('option');
var selectOptionsIds = _.map(selectOptions, 'value');
if (! _.includes(selectOptionsIds, value)) {
var missingOption = _.find(this.options, {id: value});
var missingText = _.find(this.options, function(opt){
return opt.id === parseInt(value);
}).text;
$(this.$el).append('<option value='+value+'>'+missingText+'</option>');
}
// update value only if there is a real change
// (without checking isSame, we enter a loop)
$(this.$el).val(value).trigger('change');
}
}
},
destroyed: function() {
$(this.$el).off().select2('destroy')
}
我說''VM。在''nextTick''裏面''讓我的select2組件聽取''change''事件 –