.subscribe在我的ASP.NET MVC應用程序中不起作用

Question

我是ASP.NET MVC開發人員。我是Knockout js的新手，目前我在應用程序中使用KO js。 Dropdownlist選擇更改（.subcribe）無法正常工作。請在下面找到我的代碼：

我的任務是：有三個下拉列表，我必須將數據綁定到第一個下拉列表的更改事件上的下一個下拉列表。 腳本：

var array_BankNames = JSON.parse(@Html.Raw(ViewBag.Banks)); 


    var Bank = function() { 
     var self = this; 
     self.BankName = ko.observableArray(array_BankNames); 
     self.SelectedBank = ko.observable(); 

     self.BankLocation = ko.observableArray(); 
     self.SelectedLocation = ko.observable(); 

     self.BankBranch = ko.observableArray(); 
     self.SelectedBranch = ko.observable(); 

     self.SelectedBank.subscribe = function() { 
      alert("Hi");    
      $.ajax({ 
       url: '@Url.Action("GetBankLocations_Data")', 
       data: { Bankname: selectedValue }, 
       type: 'GET', 
       success: function (data) { 
        self.BankLocation(data); 
       } 
      }); 
     }.bind(self); 
    }; 

    var BanksModel = function() { 
     var self = this; 
     self.Banks = ko.observableArray([new Bank()]); 

     self.addBank = function() { 
      self.Banks.push(new Bank()); 
     }; 

     self.removeBank = function (Bank) { 
      self.Banks.remove(Bank); 
     }; 
    }; 
    ko.applyBindings(new BanksModel()); 

HTML：

     <div class="col-sm-9 col-md-8 controls">        
           <select data-bind=" 
            options: BankName, 
            optionsValue: 'ID', 
            optionsText: 'Name', 
            value: SelectedBank"> 
          </select> 
         </div> 
        </div> 
       </div> 
       <div class="col-md-6"> 
        <div class="form-group"> 
         @Html.LabelFor(model => model.BankLocation, new { @class = "col-sm-3 col-md-4 control-label" }) 
         <div class="col-sm-9 col-md-8 controls"> 

          <select data-bind="options: BankLocation, 
          optionsValue: 'ID', optionsText: 'Name', value: $root.SelectedLocation"> 
          </select> 
         </div> 
        </div> 
       </div> 
      </div> 

      <div class="col-md-12"> 
       <div class="col-md-6"> 
        <div class="form-group"> 
         @Html.LabelFor(model => model.BankBranch, new { @class = "col-sm-3 col-md-4 control-label" }) 
         <div class="col-sm-9 col-md-8 controls"> 

          <select data-bind="options: BankBranch, 
            optionsValue: 'ID', optionsText: 'Name', value: SelectedBranch"> 
          </select> 
         </div> 
        </div> 
       </div> 

Answer 1

我得到了我的問題的答案：

self.LoadLocations = ko.computed(function() { 
       var tempreview = self.SelectedBank(); 
       return tempreview; 
      }), 
      self.LoadLocations.subscribe(function (newValue) { 
       $.ajax({ 
        url: '@Url.Action("GetBankLocations_Data")', 
        data: { Bankname: newValue }, 
        type: 'GET', 
        success: function (data) { 
         self.BankLocation(data); 
        } 
       }); 
      }); 

這是在我的項目中級聯下拉列表的腳本。

Answer 2

從AJAX回調的背景下，該模型是不BanksModel，這是self ......這樣：

self.SelectedBank.subscribe = function() { 
    alert("Hi"); 
    $.ajax({ 
     url: '@Url.Action("GetBankLocations_Data")', 
     data: { Bankname: SelectedBank() }, 
     type: 'GET', 
     success: function (data) { 
      self.BankLocation(data); 
     } 
    }); 
    $.getJSON('@Url.Action("GetBankLocations_Data")', SelectedBank, function (data) { 
     self.BankLocation(data); 
    })