c# - 如何通过 knockout 保存单条记录

Question

我有一个使用 knockout 设置的基本表，但我想知道是否有任何方法可以编辑/保存单个记录，而不是每次进行更改时都必须保存整个 View 模型？这是我的代码...

<tbody data-bind="foreach: movies">
    <tr> 
        <td data-bind="text: title"></td>
        <td data-bind="text: releaseDate"></td>
        <td data-bind="text: genre"></td>
        <td data-bind="text: price"></td>
        <td><input type="button" value="Edit" id="edit"/></td>
    </tr>
    <tr class="editable"> <!-- hide this initially, only show when edit button is   clicked -->
        <td><input id="titleInput" data-bind="value: title" /></td>
        <td><input id="releaseDateInput" data-bind="value: releaseDate" /></td>
        <td><input id="genreInput" data-bind="value: genre" /></td>
        <td><input id="priceInput" data-bind="value: price" /></td>
    </tr>
 <!-- save button/form or something here containing ONLY this record -->

</tbody>
</table>


<script type="text/javascript">

function Film(data) {
    this.title = ko.observable(data.Title);
    this.releaseDate = ko.observable(data.ReleaseDate);
    this.genre = ko.observable(data.Genre);
    this.price = ko.observable(data.Price);
}

function MovieListViewModel() {
    var self = this;
    self.movies = ko.observableArray([]);
    self.title = ko.observable();
    self.releaseDate = ko.observable();
    self.genre = ko.observable();
    self.price = ko.observable();

    $.getJSON("/Movies/GetAllMovies", function (allMovies) {
        var mappedMovies = $.map(allMovies, function (movie) { return new Film(movie)    });
        self.movies(mappedMovies);
    });
}

ko.applyBindings(new MovieListViewModel());

有什么想法吗？谢谢!

Answer 1

事实上，通过的魔力binding contexts ，这很简单!

1. 第一步。将以下元素放置在 foreach 模板内的任意位置。

   <button data-bind="click: $root.saveMovie">Save</button>
   

2. 第二步。将 saveMovie 方法添加到您的 viewModel

   self.saveMovie = function(movie) {
       $.ajax({
           type: "POST",
           url: "/someurl",
           dataType: "json",
           contentType: "application/json",
           data: ko.toJSON(movie),
           success: function(result) {
               //...
           }
       });
   }
   

movie 变量将包含 foreach 循环的项目!为什么？因为在 Knockout 中，我们有一个令人惊奇的功能，称为绑定(bind)上下文:

A binding context is an object that holds data that you can reference from your bindings. While applying bindings, Knockout automatically creates and manages a hierarchy of binding contexts. The root level of the hierarchy refers to the viewModel parameter you supplied to ko.applyBindings(viewModel). Then, each time you use a control flow binding such as with or foreach, that creates a child binding context that refers to the nested view model data.

http://knockoutjs.com/documentation/binding-context.html