这是我使用Knockout绑定的Gridstack布局示例。问题是我的观点不会根据模型进行更新。
按Delete me后，控制台输出显示widgets可观察数组正确更新，而视图不正确。原因似乎是在这一行（没有被调用）：
ko.utils.domNodeDisposal.addDisposeCallback(item, function () {
self.grid.removeWidget(item);
});
据我所知，foreach绑定应该自动更新，为什么它不会？
var ViewModel = function() {
var self = this;
self.grid = null;
self.widgets = ko.observableArray([{
x: 0,
y: 0,
width: 1,
height: 1
}, {
x: 0,
y: 1,
width: 1,
height: 1
}]);
self.deleteWidget = function(item) {
console.log("widgets before", self.widgets());
self.widgets.remove(item);
console.log("widgets after", self.widgets());
return false;
};
self.afterAddWidget = function(items) {
if (self.grid == null) {
self.grid = $('.grid-stack').gridstack({
auto: false
}).data('gridstack');
}
var item = _.find(items, function(i) {
return i.nodeType == 1
});
self.grid.addWidget(item);
ko.utils.domNodeDisposal.addDisposeCallback(item, function() {
self.grid.removeWidget(item);
});
};
};
ko.applyBindings(new ViewModel());.grid-stack {
background: lightgoldenrodyellow;
}
.grid-stack-item-content {
color: #2c3e50;
text-align: center;
background-color: #18bc9c;
}<link rel="stylesheet" href="https://raw.githubusercontent.com/troolee/gridstack.js/master/dist/gridstack.css" />
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js" type="text/javascript"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.0/jquery-ui.js" type="text/javascript"></script>
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js" type="text/javascript"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/lodash.js/3.5.0/lodash.min.js" type="text/javascript"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js" type="text/javascript"></script>
<script type="text/javascript" src="https://rawgit.com/troolee/gridstack.js/master/dist/gridstack.js"></script>
<div class="grid-stack" data-bind="foreach: {data: widgets, afterRender: afterAddWidget}">
<div class="grid-stack-item" data-bind="attr: {'data-gs-x': $data.x, 'data-gs-y': $data.y, 'data-gs-width': $data.width, 'data-gs-height': $data.height, 'data-gs-auto-position': $data.auto_position}">
<div class="grid-stack-item-content">
<button data-bind="click: $root.deleteWidget">Delete me</button>
</div>
</div>
</div>
答案 0 :(得分：2)
问题实际上是由</div>结束标记之间的额外空格字符引起的。 example警告说。在我的情况下，它是由代码格式化程序自动插入的，所以它没有引起注意。 HTML模板中的行应为</div></div><!-- <---- NO SPACE BETWEEN THESE CLOSING TAGS -->， </div></div>
var ViewModel = function() {
var self = this;
self.grid = null;
self.widgets = ko.observableArray([{
x: 0,
y: 0,
width: 1,
height: 1
}, {
x: 0,
y: 1,
width: 1,
height: 1
}]);
self.deleteWidget = function(item) {
console.log("widgets before", self.widgets());
self.widgets.remove(item);
console.log("widgets after", self.widgets());
return false;
};
self.afterAddWidget = function(items) {
if (self.grid == null) {
self.grid = $('.grid-stack').gridstack({
auto: false
}).data('gridstack');
}
var item = _.find(items, function(i) {
return i.nodeType == 1
});
self.grid.addWidget(item);
ko.utils.domNodeDisposal.addDisposeCallback(item, function() {
self.grid.removeWidget(item);
});
};
};
ko.applyBindings(new ViewModel());.grid-stack {
background: lightgoldenrodyellow;
}
.grid-stack-item-content {
color: #2c3e50;
text-align: center;
background-color: #18bc9c;
}<link rel="stylesheet" href="https://raw.githubusercontent.com/troolee/gridstack.js/master/dist/gridstack.css" />
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js" type="text/javascript"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.0/jquery-ui.js" type="text/javascript"></script>
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js" type="text/javascript"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/lodash.js/3.5.0/lodash.min.js" type="text/javascript"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js" type="text/javascript"></script>
<script type="text/javascript" src="https://rawgit.com/troolee/gridstack.js/master/dist/gridstack.js"></script>
<div class="grid-stack" data-bind="foreach: {data: widgets, afterRender: afterAddWidget}">
<div class="grid-stack-item" data-bind="attr: {'data-gs-x': $data.x, 'data-gs-y': $data.y, 'data-gs-width': $data.width, 'data-gs-height': $data.height, 'data-gs-auto-position': $data.auto_position}">
<div class="grid-stack-item-content">
<button data-bind="click: $root.deleteWidget">Delete me</button>
</div>
</div></div><!-- <---- NO SPACE BETWEEN THESE CLOSING TAGS -->
答案 1 :(得分：1)
Gridstack是一个控制DOM的小部件。你需要某种绑定处理程序来使Knockout与控制DOM的小部件很好地协同工作。
看起来你可能正在this example工作。它以一种内置绑定处理程序的方式使用组件。它似乎有效，但我建议将DOM操作放在最佳位置：绑定处理程序。
更新：以下是将gridstack代码放入绑定处理程序的示例。它只是包装foreach绑定处理程序，并在更新中为其添加afterRender选项。现在，viewmodel看起来像一个viewmodel，你可以在页面上处理多个gridstack而不$(.grid-stack)选错了。
ko.bindingHandlers.gridstack = {
init: function(element, valueAccessor, allBindingsAccessor, data, context) {
ko.bindingHandlers.foreach.init(element, valueAccessor, allBindingsAccessor, data, context);
return {
controlsDescendantBindings: true
};
},
update: function(element, valueAccessor, allBindingsAccessor, data, context) {
var widgets = valueAccessor(),
grid = $(element).gridstack().data('gridstack'),
afterAddWidget = function(items) {
var item = _.find(items, function(i) {
return i.nodeType === 1;
});
grid.addWidget(item);
ko.utils.domNodeDisposal.addDisposeCallback(item, function() {
grid.removeWidget(item);
});
},
newVA = function() {
return {
data: widgets,
afterRender: afterAddWidget
};
};
ko.bindingHandlers.foreach.update(element, newVA, allBindingsAccessor, data, context);
}
};
var ViewModel = function() {
var self = this;
self.grid = null;
self.widgets = ko.observableArray([{
x: 0,
y: 0,
width: 1,
height: 1
}, {
x: 0,
y: 1,
width: 1,
height: 1
}]);
self.deleteWidget = function(item) {
self.widgets.remove(item);
};
};
ko.applyBindings(new ViewModel());.grid-stack {
background: lightgoldenrodyellow;
}
.grid-stack-item-content {
color: #2c3e50;
text-align: center;
background-color: #18bc9c;
}<link rel="stylesheet" href="https://raw.githubusercontent.com/troolee/gridstack.js/master/dist/gridstack.css" />
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js" type="text/javascript"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.0/jquery-ui.js" type="text/javascript"></script>
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js" type="text/javascript"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/lodash.js/3.5.0/lodash.min.js" type="text/javascript"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-debug.js" type="text/javascript"></script>
<script type="text/javascript" src="https://rawgit.com/troolee/gridstack.js/master/dist/gridstack.js"></script>
<div class="grid-stack" data-bind="gridstack: widgets">
<div class="grid-stack-item" data-bind="attr: {'data-gs-x': $data.x, 'data-gs-y': $data.y, 'data-gs-width': $data.width, 'data-gs-height': $data.height, 'data-gs-auto-position': $data.auto_position}">
<div class="grid-stack-item-content">
<button data-bind="click: $parent.deleteWidget">Delete me</button>
</div>
</div></div><!-- <---- NO SPACE BETWEEN THESE CLOSING TAGS -->