knockoutjs：为什么发送的是一个空对象？

Question

我正在尝试使用knockoutjs 编写rails3 crud 视图。不知何故，我得到的行为与教程完全不同，如果您能给我一些提示，我将不胜感激...

我的代码更多的是 加载和保存数据教程。我从服务器加载数据，什么都不做，保存，控制器获取额外的“空”对象，该对象以某种方式被持久化。然而，对现有数据的更改永远不会发生，也不会被删除。

我可以显示代码：

%ul#folders{'data-bind' => 'foreach: folders, visible: folders().length > 0'}
  %li
    %span{'data-bind' => 'text: id'}
    %span{'data-bind' => 'text: name'}
    %span{'data-bind' => 'text: description, visible: description'}
    %a{'data-bind' => 'click: $parent.removeFolder'}Excluir

%button{'data-bind' => 'click: save'}Salvar

%form{'data-bind' => 'submit: addFolder'}
  Add folder:
  %input{'data-bind' => 'value: newFolderName', 'placeholder'=>"Nome"}
  %button{type: "submit"}Adicionar

=content_for :script do
  :javascript

    function Folder(data) {
      data = data || {id: 0, name: "", description: ""};
      this.id = data.id;
      this.name = ko.observable(data.name);
      this.description = ko.observable(data.description);
    }

    function FolderListViewModel() {
      var self = this;
      self.folders = ko.observableArray([]);
      self.newFolderName = ko.observable();

      $.getJSON("/folders", function(allData) {
        var mappedFolders = $.map(allData, function(item) {
          return new Folder(item);
        });
        self.folders(mappedFolders);
      });

      self.addFolder = function() {
        self.folders.push(new Folder({name: self.newFolderName()}));
        self.newFolderName("");
      };

      self.removeFolder = function(folder) {
        self.folders.remove(folder);
      };

      self.save = function() {
        console.log(self.folders());
        $.ajax("/folders", {
          data: ko.toJSON({folders: self.folders}),
          type: "post",
          contentType: "application/json",
          success: function(result) {
            return console.log(result);
          }
        });
      };
    }

    $(function(){
      ko.applyBindings(new FolderListViewModel());
    });

保存（无论是否有更改都是独立的）总是会产生类似的请求：

Started POST "/folders" for 127.0.0.1 at 2012-01-04 22:57:40 +0100
  Processing by FoldersController#create as */*
  Parameters: {"folders"=>[{"id"=>2, "name"=>"dim sum", "description"=>"ist warm!"}, {"id"=>3, "name"=>"Sushi", "description"=>"roh und kalt"}, {"id"=>1, "name"=>"Spagetti", "description"=>"Carbonara"}, {"id"=>10, "name"=>"Wiener", "description"=>"vom Kalb"}, {"id"=>11, "name"=>"Feijão", "description"=>""}], 
"folder"=>{}} <== LOOK HERE
  Folder Load (0.3ms)  SELECT "folders".* FROM "folders" ORDER BY "folders"."row_order"
   (0.1ms)  BEGIN
  Folder Load (0.2ms)  SELECT id, row_order FROM "folders" ORDER BY "folders"."row_order" DESC LIMIT 1
  Folder Load (0.2ms)  SELECT id, row_order FROM "folders" WHERE "folders"."row_order" = 8388592 LIMIT 1
  SQL (0.4ms)  INSERT INTO "folders" ("created_at", "description", "name", "row_order", "updated_at") VALUES ($1, $2, $3, $4, $5) RETURNING "id"  [["created_at", Wed, 04 Jan 2012 21:57:40 UTC +00:00], ["description", nil], ["name", nil], ["row_order", 8388592], ["updated_at", Wed, 04 Jan 2012 21:57:40 UTC +00:00]]
   (0.5ms)  COMMIT
Redirected to http://0.0.0.0:3000/folders/21
Completed 302 Found in 54ms

删除的对象也只会从数组中删除，我想知道rails应该如何弄清楚，它应该将它们从对象存储中删除。 ..一切都只是一个帖子...这对我来说看起来都是错误的。 我的错误是什么？

两个奖励问题： 我不喜欢用这些构造函数来填充我的全局 js 命名空间，但如果我尝试将它们隐藏在匿名函数中，似乎 ko 再也找不到它们了。这可以补救吗？

我怎样才能全局告诉 Rails，停止将我重定向到 json 请求上的 html 操作（无论如何，这有多愚蠢），而只是向我发送一条 ok 消息或错误消息？

Answer 1

对于全局变量，您可以通过为它们创建命名空间和/或将此页面的代码包装在代表视图模型的函数/对象中来解决此问题。例如：

var my = my || {}； // 你的命名空间。可能会在整个应用程序的一个地方定义它。

然后，您可以像平常一样定义视图模型，甚至将其包装在自调用函数中（如下所示）。我强烈推荐视图模型方法，因此页面的所有行为都挂在一个对象上。

(function (my, ko) {
    "use strict";
    my.viewmodel = {
        firstName: ko.observable(),
        lastName: ko.observable()
    };
}(my, ko));