Knockout可排序绑定顺序 [英] Knockout Sortable bind Order

问题描述

这是一个问题的后续问题： KnockoutJS Sortable group observableArray by field and conditionally sort

This is a follow up to a question: KnockoutJS Sortable group observableArray by field and conditionally sort

还有两件事我正在努力实现。首先，当嵌套列表项被拖动到另一个列表而父项为空时，我想删除父项。我通过创建一个afterMove函数并检查sourceParent长度是否为0来完成此操作。然后我查看路由以查看是否有任何空任务数组并相应地删除。我想知道这是否是一个有效的解决方案。我还必须删除任务，否则任务订阅会在删除计划任务时添加重复项。

There are two further things I am battling to achieve. First when a nested list item is dragged to another list leaving the parent empty I would like to remove the parent. I have done this by creating an afterMove function and checking if the sourceParent length is 0. Then I look through the routes to see if any have an empty tasks array and remove accordingly. I would like to know if this is an efficient solution. I also have to remove the tasks otherwise the tasks subscription adds duplicates when removing scheduled tasks.

其次，最重要的是基础对象（Task）具有订单属性。我想将此绑定到可排序的顺序，以便在Scheduled列表中拖动任务时更新order属性。如何从可排序的回调中访问其他列表项的顺序？

Second and most importantly the base object (Task) has an order property. I would like to bind this to the sortable order so that when the tasks are dragged around the Scheduled list the order property is updated. How do I access the order of other list items from the sortable callback?

请参阅以下小提琴。

非常感谢任何帮助。

推荐答案

对于第一个问题，您可以采用稍微优化的方式。 arg.sourceParent 包含在您要删除的 tasksByRoute 项目中。 remove 函数可以使用函数来对项目运行。所以，你可以这样写：

For the first issue, there is a slightly optimized way that you could do it. arg.sourceParent is contained in the tasksByRoute item that you want to remove. The remove function can take a function to run against the items. So, you could write it like:

self.afterMoveCallback = function(arg) {
    if (arg.sourceParent().length === 0) {
        self.tasksByRoute.remove(function(route) {
           return route.tasks === arg.sourceParent; 
        });
    }
};

对于第二个问题，我真的想使用一个会自动跟踪observableArray中的顺序的扩展名。它看起来像：

For the second issue, I really like to use an extension that will automatically track the order in an observableArray. It would look something like:

//track an index on items in an observableArray
ko.observableArray.fn.indexed = function(prop) {
    prop = prop || 'index';
   //whenever the array changes, make one loop to update the index on each
   this.subscribe(function(newValue) {
       if (newValue) {
           var item;
           for (var i = 0, j = newValue.length; i < j; i++) {
               item = newValue[i];
               if (!ko.isObservable(item[prop])) {
                  item[prop] = ko.observable();
               }
               item[prop](i);  //add 1 here if you don't want it to be zero based
           }
       }   
   }); 

   //initialize the index
   this.valueHasMutated(); 
   return this;
};

在您的情况下，您可以使用它：

in your case, you would use it like:

self.scheduledTasks = ko.observableArray([
    new Task(8, 4, "Route 4", "Cust 8", 1),
    new Task(9, 4, "Route 4", "Cust 9", 2),
    new Task(10, 5, "Route 5", "Cust 10")
    ]).indexed("order");

以下是更新这两项更改的示例： http://jsfiddle.net/rniemeyer/usVKQ/

Here is a sample updated with both of these changes: http://jsfiddle.net/rniemeyer/usVKQ/

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