数组更改时VueJS dom不刷新 [英] VueJS dom doesn't refresh when array changed

问题描述

我有一个名为"sortable"的自定义指令，但是我遇到了DOM问题.问题是当我拖放项目时，数组已更改，但DOM没有更改.

I have a custom directive called "sortable" but I ran into a problem with the DOM. The problem is when I dragged and dropped an item the array is changed but the DOM isn't.

这是我的自定义指令:

 Vue.directive('sortable', {
    bind: function(el, binding, vnode) {
        // Initialize sortable
        this.sortable = Sortable.create(el, {});
        console.debug("Sortable initialized");

        this.sortable.option("onUpdate", function(event) {
            binding.value.move(event.oldIndex, event.newIndex);
            var updated = binding.value;
            Vue.set(tasks, updated);
        });
    }
});

这就是我创建Vue实例的方式:

app = new Vue({
    el: "#app",
    data: {
        subtotal: 0,
        tasks: [
            {name: '', quantity: '', rate: 80, costs: ''}
        ]
    },
    methods: {
        newTask: function() {
            this.tasks.push({name: '', quantity: '', rate: 80, costs: ''})
        },
        deleteTask: function(index) {
            this.tasks.splice(index, 1);
            this.calculateTotal();
        },
        calculateCosts: function(event, value, index) {
            this.tasks[index].costs = event.target.value * value;
            this.calculateTotal();
        },
        calculateTotal: function() {
            this.subtotal = 0;
            _.forEach(this.tasks, $.proxy(function(task) {
                this.subtotal += task.costs;
            }, this));
        }
    }
});

在我的模板中，我使用:v-for="(task, index) in tasks".我有什么问题吗?

In my template I use: v-for="(task, index) in tasks". Did I something wrong?

推荐答案

按照

As per the documentation, the following methods will trigger view updates. The wrapped methods are:

• push()
• pop()
• shift()
• unshift()
• splice()
• sort()
• reverse()

但是我看到您也在calculateCosts方法中执行此分配，由于腔室在Vue中:

However I see you are also doing this assignment in calculateCosts method, which will not trigger the mutation, due to caveats in vue:

this.tasks[index].costs = event.target.value * value;

可以用以下内容替换它，以触发变异并借助 Vue.设置:

This can be replaced with the following to trigger the mutation and update the view with the help of Object.assign and Vue.set:

var newVal = Object.assign({}, this.tasks[index], {costs: event.target.value * value})
Vue.set(this.tasks, index, newVal)

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