Question

我有一个下拉列表（选择/选项），它应该在更改时进行整页刷新（重新加载）..（我在更改时设置cookie值...）

会发生什么：

当我在subscribe中使用window.location.reload（）时（参见下面的代码），它最终会出现在无限重载循环中。

我该如何避免这种情况？

选择控件

<select id="ddlSelectDepartment" class="form-control" data-bind="options: departments, optionsCaption: 'Alle', optionsText: 'name', optionsValue: 'id', value: selectedDepartment"></select>

淘汰赛处理

$(document).ready(function() {

var selDepCookie = JSHelpers.readCookie("seldep");
console.log("COOKIEMONSTER! " + selDepCookie);

var DepModel = function() {
    var self = this;
    self.departments = ko.observableArray();
    self.selectedDepartment = ko.observable(0);
    self.selectedDepartment.subscribe(function (latest) {
        //console.log("Input changed");
        JSHelpers.setCookie('seldep', latest);
        window.location.reload();  // this ends in a infinite loop !
    }, self);
}

var urlForSelectDepartment = 'api/Customer/GetDepartmentsFull';

$.ajax({
    type: 'GET',
    url: urlForSelectDepartment,
    success: function (data) {
        depmodel.departments(data);
    },
    error: function (e) {
        console.log(e);
    },
    dataType: "json",
    contentType: "application/json"
});

var depmodel = new DepModel();
ko.applyBindings(depmodel, 
document.getElementById("selectDepartmentContainer"));
});

Answer 1

尝试将selectedDepartment的初始值设置为undefined而不是0.现在，您的下拉列表将使用初始值进行渲染，该初始值不会存在于选项列表中（因为选项后来从ajax调用到达）因此，它必须将selectedDepartment observable从0修改为undefined，这将触发您的订阅。

{
  "$schema": "http://json-schema.org/draft-06/schema#",
  "oneOf": [
    {
      "properties": {
        "A": {"type": "number"},
        "B": {"type": "null"},
        "C": {"type": "null"},
        "D": {"type": "null"}
      },
      "required": ["A"]
    },
    {
      "properties": {
        "A": {"type": "null"},
        "B1": {"type": ["number","null"]},
        "B2": {"type": ["number","null"]},
        "B3": {"type": ["number","null"]}
      },
      "anyOf": [
        {"required": ["B1"]},
        {"required": ["B2"]},
        {"required": ["B3"]}
      ]
    },
    {
      "properties": {
        "A": {"type": "null"},
        "B1": {"type": "null"},
        "B2": {"type": "null"},
        "B3": {"type": "null"}
      }
    }
  ]
}

Knockout.js：带有window.location.reload（）的observable.subscribe导致无限重载循环

1 个答案: