如何使用Knockout迭代select中的项以显示范围值

是否有一种方法可以遍历选择列表中的项并计算值?例如，我有以下数据

"因素":[20.40，60岁,80年,One hundred.)

当前显示在多个选择列表框中，我在HTML语句中计算级别0级:20一级:40二级:60三级:80四级:100

我想计算并显示一个起始值如下;0级:0-20一级:21-40等级2:41-60三级:61-80四级:81-100

当我显示当前级别时，如何在knockout中返回到上一个级别?例如，在选择列表框中，我显示的是100，前面的等级是80，但是当我显示100时，我想显示前面的等级+ 1，当前等级为100。四级:81-100

这些值可以被用户修改，所以他们可以输入15、45、70、80、100的因数。然后我想根据这些数字显示一个范围值，例如0-15、16-45等。

在knockout/javascript/html

HTML:

 <select id="factorsSelect" multiple="multiple" size="10" data-bind="options:factors, selectedOptions:selectedFactors, 
          optionsText: function(factor) {return 'Level ' + factors().indexOf(factor) + ': ' + factor}"></select>

JavaScript:

   function FactorInfo(projectid, adjustmentfactor, listpoints) {
    this.projectid = ko.observable(projectid);
    this.adjustmentfactor = ko.observable(adjustmentfactor);
    this.listpoints = ko.observableArray(listpoints);

    this.displayFactorName = ko.dependentObservable(function () {
        return this.projectid() + " -- " + this.adjustmentfactor();
    }, this);
}

    // Factor construction
    var Factor = function () {
        this.factor = ko.observable();
    };
   // get project trusted data from wcf service
    $.getJSON("../../Home/GetProjectTrustSettings", function (jsonData) {
        var mappedGlobal = $.map(jsonData, function (item) {
            vm.adjustmentFactor(item.AdjustmentFactor);
            vm.mySelectedproject(item.ProjectId);
            vm.factors(item.ListPoints);
            return new FactorInfo(item.AdjustmentFactor, item.ProjectId, item.ListPoints);
        });
    });

     var vm = {
        //app observables
        levelIdSize: ko.observable(""),
        myGlobal: ko.observableArray([]),
        // percent tab observables
        percents: ko.observableArray([]),
        percentlevelids: ko.observableArray([]),
        selectedPercents: ko.observableArray([]).trackDirtyFlag(),
        percentItemToAdd: ko.observable(""),
        globalPercent: ko.observable("").extend({ required: "Enter a Global Percent, between 1 and 100." }).trackDirtyFlag(),
        levelSize: ko.observable(""),

        // factor tab observables
        factors: ko.observableArray([]),
        factorlevelids: ko.observableArray([]),
        selectedFactors: ko.observableArray([]).trackDirtyFlag(),
        factorItemToAdd: ko.observable(""),
        adjustmentFactor: ko.observable("").extend({ required: "Enter an Adjustment Factor, between 1 and 100." }).trackDirtyFlag(),
        // project observable
        myProject: ko.observableArray([]),
        mySelectedproject: ko.observable("1"),
        projectIdChange: ko.observable(false),
        // check if something changes with project ID
        setProjectDirtyFlag: function () {
            this.projectIdChange(true);
            //console.log(this.projectIdChange());
        }
    };

使用MVC格式:模型:使用系统;使用System.Collections.Generic;使用来;使用包含;

 namespace AuditReview.Models
 {
 public class ProjectTrustSetting
   {
    public string ProjectId { get; set; }
    public int AdjustmentFactor { get; set; }
    public List<int> ListPoints { get; set; }
   }
 }

控制器样本数据:

  public JsonResult GetProjectTrustSettings()
    {
        //create list
        var trustSetting = new List<ProjectTrustSetting>
            {
                new ProjectTrustSetting
                    {
                        ProjectId = "30729",
                        AdjustmentFactor = 5,
                        ListPoints = new List<int>
                            { 20, 40, 60, 80, 100} 
                    }
            };
        return Json(trustSetting, JsonRequestBehavior.AllowGet);
    }

寻找创建起始范围值的最佳方法，无论是在knockout,HTML, JavaScript中。我在想应该有一些方法在HTML中做到这一点，在我已经拥有的功能内。

optionsText: function(factor){返回'Level ' + factors(). indexof (factor) + ': ' + factor}，或在knockout中作为计算观察值或任何其他建议。

感谢您的帮助

<select data-bind="options: levels, 
                   optionsText: label, 
                   selectedOptions: selectedLevels" multiple="true"></select>
self.label = function(level) {
    var index = self.levels().indexOf(level);
    if (index === 0) {
        return level.name() + " 0-" + level.level();
    } else {
        var floor = self.levels()[index -1].level() + 1;
        return level.name() + " " + floor + "-" + level.level();
    }
};