Bootstrap 切换按钮的淘汰赛绑定

Question

我正在寻找一种在 KnockoutJS 中将切换按钮绑定到选择特定值（按钮）时调用的函数的方法。

我尝试了几种解决方案并得到它运行只是 KnockoutJS，但是当我向它添加 Boostrap 时，它仍然不起作用。

此处显示的我的代码不会触发与 checked 事件关联的处理函数。对于最新的工作示例，请使用 JSFiddle。

HTML:

<div id="access-rights-control" class="btn-group pull-right" data-toggle="buttons">
  <label class="btn btn-xs">
    <input type="radio" name="status" value="1" id="status-published" data-bind="checked: $root.allowAccessHandler" />Allow access
  </label>
  <label class="btn btn-xs active">
    <input type="radio" name="status" value="0" id="status-draft" checked /> No change
  </label>
</div>

JS:

var viewModel = function() {
  this.allowAccessHandler = function() {
    alert("Works!");
  }
};
ko.applyBindings(new viewModel());

JSFiddle： http://jsfiddle.net/p8nSe/191/

Answer 1

也许您想要的就像下面的代码片段所做的那样。请查看并给我反馈。

ko.bindingHandlers["bsChecked"]  ={
  init: function(element, valueAccessor){
    ko.utils.registerEventHandler(element,"change",function(event){
        var check = $(event.target);
        valueAccessor()(check.val());      
    });
  }
 
};

var viewModel = function() {
  
  this.checkedButton = ko.observable("2").extend({ notify: 'always' });
  
  this.checkedButton.subscribe( function(checkedVal) {
    // here you can decide what to do depends on the new checkedVal
    alert("Works! : "+ checkedVal);
  },this); 
  
};
ko.applyBindings(new viewModel());

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap-theme.min.css" rel="stylesheet"/>
<link href="https://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" rel="stylesheet"/>
<script src="https://netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>

<div id="access-rights-control" class="btn-group pull-left" data-toggle="buttons">
    <label class="btn btn-xs btn-default">
    <input type="radio" name="status" value="1" data-bind="bsChecked: checkedButton" />Allow access
  </label>
  <label class="btn btn-xs btn-default">
    <input type="radio" name="status" value="2" data-bind="bsChecked: checkedButton" />No change
  </label>
</div>

更新

Created a binding handler to take care about the prevent changes caused by bootstrap, so this is a workaround and I suggest to you read about KO custom bindings and implement the update function of the binding handler.

Answer 2

如果你想要在点击 input 时运行的东西，那么你需要使用 event binding not the checked 绑定（它只是将选中的状态绑定到一个可观察的状态，它是不是事件处理程序）。类似于：

var viewModel = function() {
  this.allowAccessHandler = function() {
    alert("Works!");
  }
};
ko.applyBindings(new viewModel());

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>
<div id="access-rights-control" class="btn-group pull-right" data-toggle="buttons">
  <label class="btn btn-xs">
    <input type="radio" name="status" value="1" id="status-published" data-bind="event: { change: $root.allowAccessHandler }" />Allow access
  </label>
  <label class="btn btn-xs active">
    <input type="radio" name="status" value="0" id="status-draft" /> No change
  </label>
</div>

现在，如果您将 checked 状态绑定到视图模型中的属性，那么将 subscribe 绑定到属性可能会更好，而不是将事件处理程序附加到 DOM，因为这将更符合分离视图和视图模型的要求。

Answer 3

我认为你有两个问题：

您没有 Bootstrap 无线电组的绑定处理程序，这意味着您的 checked 绑定将不起作用
您没有正确使用 checked 绑定。

第二个我可以帮你。在所有元素具有相同 name 属性和不同 value 属性的单选组中，绑定到 checked 可观察对象的变量将获得所选单选项的值。

您可以订阅可观察对象并在它获得特定值时采取行动。

var viewModel = function() {
  this.radioSelected = ko.observable();
  this.radioSelected.subscribe(function(newValue) {
    console.debug("Comparing", newValue, '1');
    if (newValue === '1') {
      alert("Works!");
    }
  });
  this.radioSelected('0');
  this.output = ko.observableArray();
};
ko.applyBindings(new viewModel());

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>
<div id="access-rights-control" class="btn-group pull-right" data-toggle="buttons">
  <label class="btn btn-xs btn-default">
    <input type="radio" name="status" value="1" data-bind="checked: radioSelected" />Allow access
  </label>
  <label class="btn btn-xs btn-default active">
    <input type="radio" name="status" value="0" data-bind="checked: radioSelected" />No change
  </label>
</div>
<div data-bind="foreach:output">
  <div data-bind="text:$data">
  </div>
</div>

同样，如果您有 Bootstrap 样式的单选按钮，这将不起作用，因为 Bootstrap 以 Knockout 未设置为检测的方式摆弄 DOM .所以你需要a binding handler that works with Bootstrap radio magic。这可能需要您的方法略有不同（即，您可能不使用 checked 绑定）我不知道。

Answer 4

最后我找到了一种本机工作并完成任务的方法。我不确定它是否是最通用的，因为我必须覆盖 ko.bindingHandlers.radio，但它有效。

ko.bindingHandlers.radio = {
      init: function(element, valueAccessor, allBindings, data, context) {
        var $buttons, $element, observable;
        observable = valueAccessor();
        if (!ko.isWriteableObservable(observable)) {
          throw "You must pass an observable or writeable computed";
        }
        $element = $(element);
        if ($element.hasClass("btn")) {
          $buttons = $element;
        } else {
          $buttons = $(".btn", $element);
        }
        elementBindings = allBindings();
        $buttons.each(function() {
          var $btn, btn, radioValue;
          btn = this;
          $btn = $(btn);
          radioValue = elementBindings.radioValue || $btn.attr("data-value") || $btn.attr("value") || $btn.text();
          $btn.on("click", function() {
            observable(ko.utils.unwrapObservable(radioValue));
          });
          return ko.computed({
            disposeWhenNodeIsRemoved: btn,
            read: function() {
              $btn.toggleClass("active", observable() === ko.utils.unwrapObservable(radioValue));
            }
          });
        });
      }
    };

    var viewModel = function() {
      this.radioSelected = ko.observable('0');
      this.radioSelected.subscribe(function(newValue) {
        console.debug("Comparing", newValue, '1');
        if (newValue === '1') {
          alert("Works!");
        }
      });
    };
    ko.applyBindings(new viewModel());

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap-theme.min.css" rel="stylesheet"/>
<link href="https://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" rel="stylesheet"/>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>

<div class="btn-group">
  <button type="button" class="btn" data-bind="radio: radioSelected, radioValue: '1'">Allow access</button>
  <button type="button" class="btn" data-bind="radio: radioSelected, radioValue: '0'">No change</button>
</div>

JSFiddle：http://jsfiddle.net/p8nSe/192/

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更新