如何在敲除绑定处理程序中更新可观察数组？

Question

I want to update the observable array in knockout binding handler. But it is not updating. The following code i tried but nothing worked out.

 this.DropdownValues = ko.observableArray([
    { id: 0, type: "Arc",Checked:false },
    { id: 1, type: "Eve",Checked:false },
    { id: 2, type: "Ca",Checked:false },
    { id: 3, type: "test",Checked:false },
 ]);

Code I have written inside binding handler.

 var value =  valueAccessor();
 var valueUnwrapped = ko.unwrap(value);
 console.log("true");
 valueUnwrapped.map(function(item){
     item[Checked]= true; return item; 
 });

 ko.utils.unwrapObservable(value(valueUnwrapped));

But my view still not detecting the values. foreach not refeshing in view.

Answer 1

You were missing quotes around the word Checked . It should be item['Checked'] or item.Checked rather than item[Checked] .

 ko.bindingHandlers.updateArray = { update: function (element, valueAccessor, allBindingsAccessor, viewModel) { var value = valueAccessor(); var valueUnwrapped = ko.unwrap(value); $("#before").text(JSON.stringify(valueUnwrapped)); console.log("true"); valueUnwrapped.map(function(item){ item['Checked']= true; return item; }); ko.utils.unwrapObservable(value(valueUnwrapped)); } } var viewModel = function(){ var self = this; self.DropdownValues = ko.observableArray([ { id: 0, type: "Arc",Checked:false }, { id: 1, type: "Eve",Checked:false }, { id: 2, type: "Ca",Checked:false }, { id: 3, type: "test",Checked:false }, ]); }; ko.applyBindings(new viewModel()); 

 <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/3.4.2/knockout-min.js"></script> Before:<br> <span id="before"></span> <div data-bind="updateArray: DropdownValues"> </div> <br><br> After:<br> <span data-bind="text: ko.toJSON(DropdownValues)"></span>