javascript - BackboneJS 未捕获引用错误 : variable is not defined

Question

我是backbonejs的新手，我可以添加并显示数据库中的联系人。但我无法使用backbonejs执行删除。 JSFiddle http://jsfiddle.net/L183kw0o/10/ 当我尝试删除它时出现错误

"Uncaught ReferenceError: Id is not defined "

下面是堆栈跟踪 (匿名函数)VM103:2 InjectedScript._evaluateOn VM69:730 InjectedScript._evaluateAndWrap VM69:669 InjectedScript.evaluate VM69:581

这是我的模型

var modelContact = Backbone.Model.extend({
    defaults: function () {
        return {
            Id: 0,
            Name: "",
            Address: ""
        };
    },
    idAttribute: "Id",
    url: function(){
        return 'api/Contact/' + this.get("Id");
    },
    initialize: function () {
        if (!this.get("Id")) {
            this.set({ "Id": this.defaults().Id });
        }
    },
    clear: function() {
        console.log(this.get("Id"));
        this.destroy({
            error: function(model, response) {
                alert("error");
            },
            success: function(model, response) {
                alert("success"); 
                console.log(response); 
            }
        });
    }
});

模型集合

var contactCollection = Backbone.Collection.extend({
    model: modelContact,
    url: function() {
        return 'api/Contact';
    }
});
var contacts = new contactCollection;

查看

var contactView = Backbone.View.extend({
    tagName: "tr",
    events: {
        "click a.destroy": "clear"
    },
    template: _.template($("#newContacttemplate").html()),
    initialize: function() {
        this.model.on("change", this.render, this);
        this.model.on('destroy', this.remove, this);
    },
    render: function () {
        if (this.isGoingToBeRemoved) {
            return (this);
        }
        this.$el.html(this.template(this.model.toJSON()));
        return this;
    },
    clear: function (e) {
       this.isGoingToBeRemoved = true;
       this.model.clear();
    }
});

所有错误均已解决，这是工作代码

Answer 1

问题来自“渲染”。

确实，您正在设置一个值并删除您的模型:

    clears: function (e) {
        console.log(e);
        console.log(this.model);
        this.model.set({ // trigger change
            Id: 3
        });
        this.model.get("Id");
        this.model.clear(); // remove your model
    }

因为 JS 是异步的，所以你会同时调用“render”和“clear”。当您调用 this.$el.html(this.template(this.model.toJSON())); 时， model.get('Id') 将已被删除。所以，你会尝试调用不存在的东西

render: function () {
    // console.log(this.model.toJSON());
    this.$el.html(this.template(this.model.toJSON())); // this.model.toJSON() == {}
    return this;
},

当您“清除”模型时，您必须阻止渲染方法。