Jquery color picker binding handler creates multip

问题:

I am trying to use this jquery color picker with knockout.js. I have written custom banding handler to bind colorpicker input control with my viewModel color value.

Here is the Binding Handler code:

ko.bindingHandlers.colorPicker = {
init: function (element, valueAccessor, allBindingsAccessor) {

    //initialize datepicker with some optional options
    var options = allBindingsAccessor().colorPickerOptions || {};
    $(element).colorPicker(options);

    //handle the field changing
    ko.utils.registerEventHandler(element, "change", function () {
        var observable = valueAccessor();
        observable($(element).colorPicker("value"));
    });

    //handle disposal (if KO removes by the template binding)
    ko.utils.domNodeDisposal.addDisposeCallback(element, function () {
        $(element).colorPicker("destroy");
    });

},
update: function (element, valueAccessor) {
    var value = ko.utils.unwrapObservable(valueAccessor());       
    $(element).colorPicker("value", value);        
}

and HTML :

 <input type="text" data-bind="colorPicker: newEvent().color, colorPickerOptions: { value:newEvent().color }"/>

Problem is that when I change the color it creates the multiple divs each time when I change the color as shown in image.

Can anyone please identiy whats the problem in my code??

回答1:

Here is the updated code for jQuery ColorPicker binding handler (to used with knockout.js libraray).

ko.bindingHandlers.jqColorPicker = {
  init: function (element, valueAccessor, allBindingsAccessor) {

    // set default value
    var value = ko.utils.unwrapObservable(valueAccessor());
    $(element).val(value);

    //initialize datepicker with some optional options
    var options = allBindingsAccessor().colorPickerOptions || {};
    $(element).colorPicker(options);

    //handle the field changing
    ko.utils.registerEventHandler(element, "change", function () {            
        var observable = valueAccessor();            
        observable($(element).val());                        
    });

    //handle disposal (if KO removes by the template binding)
    ko.utils.domNodeDisposal.addDisposeCallback(element, function () {
        $(element).colorPicker("destroy");
    });

  },
  update: function (element, valueAccessor, allBindingsAccessor) {
    var value = ko.utils.unwrapObservable(valueAccessor());
    $(element).val(value);        
    $(element).change();        
  }
};

回答2:

In your update code you're effectively creating new colorpickers.

When the color changes, the update function is called and there you create a new picker. If you try '$(element).colorPicker("value", value);' in firebug, you will see it's not a setter, but a constructor.