我想创建一个"fadeInIf"自定义绑定。我的想法是等于"fadeVisible"从:http://knockoutjs.com/examples/animatedTransitions.html:
// Here's a custom Knockout binding that makes elements shown/hidden via jQuery's fadeIn()/fadeOut() methods
// Could be stored in a separate utility library
ko.bindingHandlers.fadeVisible = {
init: function(element, valueAccessor) {
// Initially set the element to be instantly visible/hidden depending on the value
var value = valueAccessor();
$(element).toggle(ko.utils.unwrapObservable(value)); // Use "unwrapObservable" so we can handle values that may or may not be observable
},
update: function(element, valueAccessor) {
// Whenever the value subsequently changes, slowly fade the element in or out
var value = valueAccessor();
ko.utils.unwrapObservable(value) ? $(element).fadeIn() : $(element).fadeOut();
}
};
我对自定义绑定很陌生,但我认为它可能是这样的:
ko.bindingHandlers.fadeInIf = {
init: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
var value = valueAccessor();
$(element).toggle(ko.utils.unwrapObservable(value));
ko.bindingHandlers.if.init(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext);
},
update: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
var value = valueAccessor();
if (ko.utils.unwrapObservable(value))
$(element).fadeIn();
ko.bindingHandlers.if.update(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext);
}
};
我已经得到了"fadeVisible"的工作,但不能工作这个,我错过了什么?
谢谢你的建议。我终于让它工作了,我错过了controlsDescendantBindings选项。结果如下:
ko.bindingHandlers.fadeIf = {
init: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
var value = valueAccessor();
$(element).toggle(ko.utils.unwrapObservable(value));
ko.bindingHandlers['if'].init(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext);
return { controlsDescendantBindings: value };
},
update: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
var value = valueAccessor();
if (ko.utils.unwrapObservable(value)) {
ko.bindingHandlers['if'].update(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext);
$(element).fadeIn();
}
else {
$(element).fadeOut(200, function () {
ko.bindingHandlers['if'].update(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext);
});
}
}
};
我认为你在99%的情况下是正确的,但是在第一次之后渐变就不会完成了…我认为这与"if"绑定处理程序的工作方式有关。我所做的是改变这个:
if (ko.utils.unwrapObservable(value))
$(element).fadeIn();
这:
if (ko.utils.unwrapObservable(value)) {
$(element).toggle(false);
$(element).fadeIn();
}
如果你想检查的话,我已经保存了一段时间。