更新数据时保留和提示排序顺序

Preserving and hinting about the sort order when updating data?

本文关键字：提示 排序 顺序 保留 数据 更新      更新时间：2023-09-26

在更新模型内部的数据时，是否可以保留排序顺序（最后是jsfiddle）？我有以下标记：

<table>
  <thead>
    <tr>
      <th data-bind="sort: { arr: Records, prop: 'Name' }">Name</th>
      <th data-bind="sort: { arr: Records, prop: 'Number' }">Number</th>
      <th data-bind="sort: { arr: Records, prop: 'Desc' }">Description</th>
    </tr>
  </thead>
  <tbody data-bind="foreach: Records">
    <tr>
      <td data-bind="text: Name"></td>
      <td data-bind="text: Number"></td>
      <td data-bind="text: Desc"></td>
    </tr>
  </tbody>
</table>
<button data-bind="click: changeMe">Remove</button>
<button data-bind="click: resetMe">Reset</button>

现在，排序本身是使用这篇原始文章中的bindingHandlers实现的：

var recs = [];
ko.bindingHandlers.sort = {
    init: function(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
        var asc = false;
        element.style.cursor = 'pointer';
        element.onclick = function(){
            var value = valueAccessor();
            var prop = value.prop;
            var data = value.arr;
            asc = !asc;
            if(asc){
                data.sort(function(left, right){
                    return left[prop] == right[prop] ? 0 : left[prop] < right[prop] ? -1 : 1;
                });
            } else {
                data.sort(function(left, right){
                    return left[prop] == right[prop] ? 0 : left[prop] > right[prop] ? -1 : 1;
                });
            }
        }
    }
};
function ViewModel(){
  var self = this;
  self.Records = ko.observableArray();
    self.changeMe = function() {
        self.Records.pop()
    }
    self.resetMe = function() {
        var recs = []
        recs.push({Name: 'Bob', Number: 1, Desc: 'I am awesome'});
        recs.push({Name: 'Joe', Number: 2, Desc: 'Another description'});
        recs.push({Name: 'Mitch', Number: 3, Desc: 'Something'});
        recs.push({Name: 'Steven', Number: 4, Desc: 'Yo'});
        self.Records(recs);   
    }
}
var viewModel = new ViewModel();
recs.push({Name: 'Bob', Number: 1, Desc: 'I am awesome'});
recs.push({Name: 'Joe', Number: 2, Desc: 'Another description'});
recs.push({Name: 'Mitch', Number: 3, Desc: 'Something'});
recs.push({Name: 'Steven', Number: 4, Desc: 'Yo'});
recs.push({Name: 'Robin', Number: 6, Desc: 'Hello'});
recs.push({Name: 'Batman', Number: 7, Desc: 'Description'});
recs.push({Name: 'John', Number: 5, Desc: 'Ok'});
viewModel.Records(recs);
ko.applyBindings(viewModel);

例如，考虑这个JSFiddle和以下一系列交互：

  • 单击某列，以便按该列对行进行排序。点击"数字"两次，使其按降序排列
  • 现在，点击"Reset"模拟ajax调用（即，假设我正在更新模型）。现在，排序顺序恢复为原来的顺序

我如何保留排序顺序，即记住它应该按"数字"降序排序？当然，在专栏旁边以某种方式显示这一点？类似于数据表的操作方式（注意每个列名旁边的上下箭头）。

有什么建议吗？

尝试了一下，但应该有更好的方法。

重点是我做了一个"dataUpdated"标志，所以每次更新数据时，都要重新对它们进行排序。此外，我在一个可观察的对象中保存"道具"answers"顺序"，这样你也可以在它们变化时做一些事情（例如，有一个箭头图标，并根据顺序进行更改）

看看

-->http://jsfiddle.net/blackjim/xgEdg/15/

var recs = [];
ko.bindingHandlers.changed = {
    update: function(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
        if(viewModel.dataUpdated()){
            console.log('data updated, sorting...');
            sortThis(viewModel.Records,viewModel.sortData().order,viewModel.sortData().col);
        }
        viewModel.dataUpdated(false);
    }
}
ko.bindingHandlers.sort = {
    init: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
        var order = 'none';    //    initial order status for this column
        if(!viewModel.Records.dataSort){
            viewModel.Records.dataSort = { col: 'none', order: 'none' };
        }
        element.style.cursor = 'pointer';
        element.sortAsc = element.sortAsc || false;
        element.onclick = function () {
            var value = valueAccessor(),
                prop = value.prop,
                data = value.arr;
            // sortData updated
            viewModel.sortData({
                col: prop,
                order: order = (order === 'asc' ? 'desc' : 'asc')
            });
            sortThis(data, order, prop);
        }
    }
};
//    function for sorting the observable array
function sortThis(data, order, prop){
    if (order === 'asc') {
        data.sort(function (left, right) {
            return left[prop] == right[prop] ? 0 : left[prop] < right[prop] ? -1 : 1;
        });
    } else {
        data.sort(function (left, right) {
            return left[prop] == right[prop] ? 0 : left[prop] > right[prop] ? -1 : 1;
        });
    }
}
function ViewModel() {
    var self = this;
    self.Records = ko.observableArray();
    self.sortData = ko.observable({
        col: "none",
        order: "none"
    });
    self.dataUpdated = ko.observable(false);    //    flag for data updating
    self.changeMe = function () {
        self.Records.pop();
    }
    self.resetMe = function () {
        self.Records.removeAll();
        self.Records.push({
            Name: 'Bob',
            Number: 1,
            Desc: 'I am awesome'
        });
        self.Records.push({
            Name: 'Joe',
            Number: 2,
            Desc: 'Another description'
        });
        self.Records.push({
            Name: 'Mitch',
            Number: 3,
            Desc: 'Something'
        });
        self.Records.push({
            Name: 'Steven',
            Number: 4,
            Desc: 'Yo'
        });
        //    trigger the dataUpdated 'event'
        self.dataUpdated(true);
    }
}
var viewModel = new ViewModel();
recs.push({
    Name: 'Bob',
    Number: 1,
    Desc: 'I am awesome'
});
recs.push({
    Name: 'Joe',
    Number: 2,
    Desc: 'Another description'
});
recs.push({
    Name: 'Mitch',
    Number: 3,
    Desc: 'Something'
});
recs.push({
    Name: 'Steven',
    Number: 4,
    Desc: 'Yo'
});
recs.push({
    Name: 'Robin',
    Number: 6,
    Desc: 'Hello'
});
recs.push({
    Name: 'Batman',
    Number: 7,
    Desc: 'Description'
});
recs.push({
    Name: 'John',
    Number: 5,
    Desc: 'Ok'
});
viewModel.Records(recs);
ko.applyBindings(viewModel);
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