javascript - knockout - 绑定(bind)从模型计算

Question

我正在尝试使用计算的可观察对象来创建自定义 div ID(例如 branch3)。但是，每当我尝试绑定(bind)计算时，我都会收到“无法解析绑定(bind)”错误。我确定我可以用不同的方式来做这件事，但我只是不明白为什么我不能在这里使用计算。我很确定我已经看到它完成了。

这是我一直在研究的 jsfiddle。

FIDDLE

var branchList   =[{"Id":1,"Latitude":40.2444400000,"Longitude":-111.6608300000,"StreetAddress":"1525 W 820 N","BranchName":"GPS","City":"Cityplacwe","State":"UT","Zip":"84601"},{"Id":2,"Latitude":40.2455550000,"Longitude":-111.6616100000,"StreetAddress":"123 N Center","BranchName":"GPS Branch 2","City":"Lehi","State":"UT","Zip":"84043"}];

//myMarkers = new Array();

var Branch = function (data) {
  var self = this;
  self.Id = ko.observable(data.Id);
  self.Latitude = ko.observable(data.Latitude);
  self.Longitude = ko.observable(data.Id);
  self.BranchName = ko.observable(data.BranchName);
  self.StreetAddress = ko.observable(data.StreetAddress);
  self.City = ko.observable(data.City);
  self.State = ko.observable(data.State);
  self.Zip = ko.observable(data.Zip);
  this.DivId = ko.computed(function () {
    return self.Id();
  });
  //self.DivId = ko.computed({
  //  //Reading from object to field
  //  read: function () {
  //    return "branch" + self.Id();
  //  },
  //  //writing from field to object
  //  write: function (value) {

  //  }
//});

}

var BranchViewModel = function () {
  var self = this;

  //create knockout array
  self.branchArrayKO = ko.observableArray(branchList);
}

和 HTML

<div data-bind="foreach: branchArrayKO">


<div data-bind="attr: {'id': DivId}">
  <p></p>
  <h2></h2>
  <ul>
    <li data-bind="text: Id"></li>
    <li data-bind="text: BranchName"></li>
    <li data-bind="text: StreetAddress"></li>
  </ul>
</div>

</div>

Answer 1

您需要将原始 JavaScript 数组转换为 Branch 数组。一种方法是使用 ko.utils.arrayMap 遍历列表中的每个项目并创建一个新的 Branch:

var BranchViewModel = function() {
    var self = this;

    //create knockout array
    self.branchArrayKO = ko.observableArray(ko.utils.arrayMap(branchList, function(branch) {
        return new Branch(branch);
    }));
}

更新示例: http://jsfiddle.net/hawMW/2/

另一个可能有用的替代方法是 knockout mapping plugin ，您可以使用它来自动执行全部或部分映射过程。