使用基因剔除和MVVM时在哪里编写dom操纵代码 [英] where to write dom manipulation code when using knockout and MVVM part 2

问题描述

大家好，我问了一个问题昨天介绍了使用淘汰赛时在哪里编码dom操纵/动画等代码.我以前已将此代码编码到视图模型中，并被告知这是不正确的.

Hi guys i asked a question yesterday about where to code dom manipulation / animations etc when using knockout. I had previously coded this into the viewmodel and was advised this is not correct.

我现在已经按照建议更新了代码并创建了自定义绑定处理程序，但是我需要从自定义绑定处理程序中调用我的viewmodel方法.特别是动画完成时.我已经这样做了

Ive now updated my code and created custom binding handlers as advised, however i need to call a method of my viewmodel from within the custom binding handler. Specifically when the animation completes. Ive done it like this

ko.bindingHandlers.slideUp = {
    init:function(element, valueAccessor, allBindingsAccessor, context){
        var allBindings = allBindingsAccessor();
        var parent = allBindings.parent;

        $(element).click(function(){
            if(parent.SelectedEmployee() === valueAccessor())return;

            var $PanelWrapper = $('#' + allBindings.panelName); 
            var $Bottom = parseInt($PanelWrapper.css("bottom"));

            if($Bottom === 0){
                $PanelWrapper.animate({
                    bottom:"-95"
                }, 500, function(){
                    parent.Select(valueAccessor());
                }).animate({
                    bottom:"0"
                }, 500);
            }else{
                parent.Select(valueAccessor());

                $PanelWrapper.animate({
                    bottom:"0px"
                }, 500);       
            }
        });
    }
}

我的绑定是

<tbody data-bind="foreach: Emps">
            <tr data-bind="slideUp: $data, parent: $parent, panelName: 'PanelWrapper'">
                <td data-bind="text: Name"></td>
            </tr>
        </tbody>

如您所见，即时消息传递了对viewmodel的引用以及我要设置动画的标签的ID.我只是想知道这是否是正确的方法.有没有更好的方法来引用视图模型，我是否正确调用了视图模型的方法，并且可以传入我想使用的html标签的ID吗?一切正常，但我渴望改进

As you can see im passing in a reference to the viewmodel and also the id of the tag i want to animate. Im just wondering if this is the correct way to do this. Is there a better way to reference the viewmodel, am i calling the method of the viewmodel correctly and is it ok to pass in the id of the html tag i want to use. It all works fine, but im keen to improve

此处是指向我的小提琴

推荐答案

您现在将绑定应用于包含员工的元素.我认为将SelectedEmployee可观察的值应用于#PanelWrapper会更好，因此您可以根据SelectedEmployee的值来显示/隐藏它:

You're now applying the binding to the element containing the employee. I think it would be better to apply the SelectedEmployee observable to the #PanelWrapper so you can show/hide it depending on the value of SelectedEmployee:

<div id="PanelWrapper" data-bind="EmployeePanel: $root.SelectedEmployee"></div>

然后输入您的JS:

ko.bindingHandlers.EmployeePanel = {
    currentEmployee: null,
    init: function(element, valueAccessor) {
        var value = valueAccessor();
        this.setEmployee(element, ko.utils.unwrapObservable(value));
    },
    update: function(element, valueAccessor) {
        var value = valueAccessor();
        this.setEmployee(element, ko.utils.unwrapObservable(value));
    },
    setEmployee: function(element, value) {
        if (value === currentEmployee) return; // already selected employee
        this.currentEmployee = value;
        if (value) {
            $(element).fadeIn(); // show and populate the panel here
        } else {
            $(element).fadeOut(); // hide the panel here
        }
    }
};

因此，现在您的员工行将如下所示:

So now your employee row will look like this:

<tr data-bind="click: $root.OnEmployeeClick">

和您的ViewModel:

self.OnEmployeeClick = function(employee) { self.SelectedEmployee(employee); };

这篇关于使用基因剔除和MVVM时在哪里编写dom操纵代码的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！