Javascript MVC，addEventListener 不能附加到 dom 元素

Question

我有这些 javascript 文件。了解 MVC 如何与 javascript 一起工作是一个非常小的测试项目。当我尝试单击“Delete Bloak”按钮时，除了 ID 为 100 的最后一个按钮外，没有任何反应。其他按钮没有附加任何单击事件。为什么？

Controller.js

    var BloakController = function BloakController(model, view) {
    this.model = model;
    this.view = view;
}

BloakController.prototype.init = function init() {
    this.view.onAddBloak = this.addBloak.bind(this);

    this.view.onDeleteBloak = this.deleteBloak.bind(this);

    this.view.onGetAllBloaks = this.getAllBloaks.bind(this);
}

BloakController.prototype.addBloak = function addBloak() {

}

BloakController.prototype.getAllBloaks = function getAllBloaks() {
    this.model.getAllBloaks(this.getAllBloaksList.bind(this));
}

BloakController.prototype.getAllBloaksList = function getAllBloaksList(allBloaksList) {
    for (var i = 0; i < allBloaksList.length; i++) {
        var bloak = allBloaksList[i];
        var bloakDataObjectModel = {
            title: bloak.title,
            body: bloak.body,
            userId: bloak.userId,
            id: bloak.id
        };

        this.view.render(bloakDataObjectModel);
    }
}

BloakController.prototype.deleteBloak = function deleteBloak(id) {
    this.model.deleteBloak(id, this.getAllBloaksList.bind(this));
}

模型.js

var BloakModel = function BloakModel(XMLHttpRequest) {
    this.XMLHttpRequest = XMLHttpRequest;
}

BloakController.prototype.addBloak = function addBloak() {

}

BloakModel.prototype.getAllBloaks = function getAllBloaks(callback) {
    var request = new this.XMLHttpRequest;

    request.onload = function onLoad(e) {
        var ajaxResponse = JSON.parse(e.currentTarget.responseText);
        callback(ajaxResponse);
    }

    request.open('GET', 'https://jsonplaceholder.typicode.com/posts', true);
    request.send();
}

BloakModel.prototype.deleteBloak = function deleteBloak(id, callback) {
    console.log(id);
    var request = new this.XMLHttpRequest;

    request.onload = function onLoad(e) {
        var ajaxResponse = JSON.parse(e.currentTarget.responseText);
        callback(ajaxResponse);
    }

    request.open('DELETE', 'https://jsonplaceholder.typicode.com/posts/' + id, true);
    request.send();
}

View.js

var BloakView = function BloakView(domElement) {
    this.domElement = domElement;

    this.onAddBloak = null;
    this.onDeleteBloak = null;
    this.onGetAllBloaks = null;
}

BloakView.prototype.render = function render(bloakDataObjectModel) {
    this.domElement.innerHTML += '<div class="bloakContainer"><h3>' + bloakDataObjectModel.title + '</h3><p class="bloakContent">' + bloakDataObjectModel.body + '</p><label class="bloakAuthor">' + bloakDataObjectModel.userId + '</label><br /><label class="bloakDate">' + bloakDataObjectModel.id + '</label><br /><input id=' + bloakDataObjectModel.id + ' type="button" value="Delete Bloak" /></div>';

    var addBloakButton = document.getElementById('addBloakButton');

    var deleteBloakButton = document.getElementById(bloakDataObjectModel.id);

    addBloakButton.addEventListener('click', this.onAddBloak);

    deleteBloakButton.addEventListener('click', this.onDeleteBloak);
}

App.js

var bloakModel = new BloakModel(XMLHttpRequest);

var targetElement = document.getElementById('bloaksContainer');
var bloakView = new BloakView(targetElement);

var bloakController = new BloakController(bloakModel, bloakView);

bloakController.init();

bloakController.getAllBloaks();

Answer 1

更新

事实证明我完全错了，做了更多的研究，看起来使用 innerHTML 属性会导致所有子元素的破坏，read more about it here .无论哪种方式，所提供的解决方案仍然有效，事实证明我自己并不知道。

我的脑袋放屁

我应该意识到我一开始是错的，如果我是对的，那么你会得到一个错误，指出你不能将事件监听器附加到 null 或 undefined，这是我犯下的糟糕、愚蠢的错误!

---

想法

非常简短地查看了您的代码后，我认为可以肯定地说您的呈现函数有些错误，因为使用了 innerHTML，它没有解析更新后的 HTML足够快让事件监听器工作......

亲自测试过，并完成了以下操作:

setTimeout(() => {
    var addBloakButton = document.getElementById('addBloakButton');
    var deleteBloakButton = document.getElementById(bloakDataObjectModel.id);
    addBloakButton.addEventListener('click', this.onAddBloak);
    deleteBloakButton.addEventListener('click', this.onDeleteBloak);
}, 10);

成功了。所以，如果你不想改变太多，你可以做我上面所做的，或者，你可以做一些类似的事情:

  var div = document.createElement("div");
  div.innerHTML = '<div class="bloakContainer"><h3>' + bloakDataObjectModel.title + '</h3><p class="bloakContent">' + bloakDataObjectModel.body + '</p><label class="bloakAuthor">' + bloakDataObjectModel.userId + '</label><br /><label class="bloakDate">' + bloakDataObjectModel.id + '</label><br /><input id=' + bloakDataObjectModel.id + ' type="button" value="Delete Bloak" /></div>';
  this.domElement.append(div);

  var addBloakButton = document.getElementById('addBloakButton');
  var deleteBloakButton = div.querySelector('input[id*="' + bloakDataObjectModel.id + '"]');
  addBloakButton.addEventListener('click', this.onAddBloak);
  deleteBloakButton.addEventListener('click', this.onDeleteBloak);

此外，作为一种更可靠的方法，我会做的是在 View 中实现一个 onRender 函数，本质上说明 once 和 only once 所有 相关 HTML 已呈现，然后触发 onRender 方法。 或者可能像view.dispatchEvents等等...特别是在这个例子中，我会在 Controller 中运行这样的函数，所以一旦getAllBloaksList 已呈现所有相关数据，您可以然后 触发dispatchEvents 函数，如下所示:

// Within the controller part... 
BloakController.prototype.getAllBloaksList = function getAllBloaksList(allBloaksList) {
  for (var i = 0; i < allBloaksList.length; i++) {
    var bloak = allBloaksList[i];
    var bloakDataObjectModel = {
      title: bloak.title,
      body: bloak.body,
      userId: bloak.userId,
      id: bloak.id
    };

    this.view.render(bloakDataObjectModel);
  }

  this.view.dispatchEvents();
};


// .. Within the View part...
BloakView.prototype.dispatchEvents = function () {
  var list = this.domElement.querySelectorAll(".bloakContainer");
  var todo = this.onDeleteBloak;

  list.forEach(function (div) {
    var deleteButton = div.querySelector("input[type=button]");

    deleteButton.onclick =  function () {
      todo(this.id);
    };
  });
};

演示

// Controller.
var BloakController = function BloakController(model, view) {
  this.model = model;
  this.view = view;
};

BloakController.prototype.init = function init() {
  this.view.onAddBloak = this.addBloak.bind(this);
  this.view.onDeleteBloak = this.deleteBloak.bind(this);
  this.view.onGetAllBloaks = this.getAllBloaks.bind(this);
};

BloakController.prototype.addBloak = function addBloak() {
  // todo
};

BloakController.prototype.getAllBloaks = function getAllBloaks() {
  this.model.getAllBloaks(this.getAllBloaksList.bind(this));
};

BloakController.prototype.getAllBloaksList = function getAllBloaksList(allBloaksList) {
  for (var i = 0; i < allBloaksList.length; i++) {
    var bloak = allBloaksList[i];
    var bloakDataObjectModel = {
      title: bloak.title,
      body: bloak.body,
      userId: bloak.userId,
      id: bloak.id
    };
    this.view.render(bloakDataObjectModel);
  }
  this.view.dispatchEvents();
};

BloakController.prototype.deleteBloak = function deleteBloak(id) {
  this.model.deleteBloak(id, this.getAllBloaksList.bind(this));
};


// Model.
var BloakModel = function BloakModel(XMLHttpRequest) {
  this.XMLHttpRequest = XMLHttpRequest;
};

BloakController.prototype.addBloak = function addBloak() {
  // todo
};

BloakModel.prototype.getAllBloaks = function getAllBloaks(callback) {
  var request = new this.XMLHttpRequest;
  request.onload = function onLoad(e) {
    var ajaxResponse = JSON.parse(e.currentTarget.responseText);
    callback(ajaxResponse);
  }
  request.open('GET', 'https://jsonplaceholder.typicode.com/posts', true);
  request.send();
};

BloakModel.prototype.deleteBloak = function deleteBloak(id, callback) {
  console.log(id);
  var request = new this.XMLHttpRequest;
  request.onload = function onLoad(e) {
    var ajaxResponse = JSON.parse(e.currentTarget.responseText);
    callback(ajaxResponse);
  }
  request.open('DELETE', 'https://jsonplaceholder.typicode.com/posts/' + id, true);
  request.send();
};


// View. 
var BloakView = function BloakView(domElement) {
  this.domElement = domElement;
  this.onAddBloak = null;
  this.onDeleteBloak = null;
  this.onGetAllBloaks = null;
};

BloakView.prototype.render = function render(bloakDataObjectModel) {
  this.domElement.innerHTML += '<div class="bloakContainer"><h3>' + bloakDataObjectModel.title + '</h3><p class="bloakContent">' + bloakDataObjectModel.body + '</p><label class="bloakAuthor">' + bloakDataObjectModel.userId + '</label><br /><label class="bloakDate">' + bloakDataObjectModel.id + '</label><br /><input id=' + bloakDataObjectModel.id + ' type="button" value="Delete Bloak" /></div>';
}

BloakView.prototype.dispatchEvents = function() {
  var list = this.domElement.querySelectorAll(".bloakContainer");
  var todo = this.onDeleteBloak;
  var addBloakButton = document.getElementById('addBloakButton');
  addBloakButton.addEventListener('click', this.onAddBloak);

  list.forEach(function(div) {
    var deleteButton = div.querySelector("input[type=button]");
    deleteButton.onclick = function() {
      todo(this.id);
    };
  });
};


// App.
var bloakModel = new BloakModel(XMLHttpRequest);
var targetElement = document.getElementById('bloaksContainer');
var bloakView = new BloakView(targetElement);
var bloakController = new BloakController(bloakModel, bloakView);

bloakController.init();
bloakController.getAllBloaks();

<button id="addBloakButton">Add</button>
<div id="bloaksContainer">
  <!-- DHTML -->
</div>