我阅读了很多教程，但我不知道如何做到这一点，这是输入
input(type="text",name="price",id="price"data-bind="text: price,valueUpdate:['afterkeydown','propertychange','input']")
这是我的viewModel
price: ko.computed(function()
{
return parseFloat(this.replace(' ','').replace(/[^0-9\.]+/g,"")) || '';
},this)
但这导致错误：这没有方法替换???我怎样才能将价格值传递给计算函数？
答案 0 :(得分：45)
最好创建自定义绑定http://knockoutjs.com/documentation/custom-bindings.html，它只接受允许的字符[0-9，。]作为数字表示。
将此行放入您的视图
<input id="text" type="text" data-bind="numeric, value: number">
将此行放入模型中（记得将数字绑定为可观察属性）
ko.bindingHandlers.numeric = {
init: function (element, valueAccessor) {
$(element).on("keydown", function (event) {
// Allow: backspace, delete, tab, escape, and enter
if (event.keyCode == 46 || event.keyCode == 8 || event.keyCode == 9 || event.keyCode == 27 || event.keyCode == 13 ||
// Allow: Ctrl+A
(event.keyCode == 65 && event.ctrlKey === true) ||
// Allow: . ,
(event.keyCode == 188 || event.keyCode == 190 || event.keyCode == 110) ||
// Allow: home, end, left, right
(event.keyCode >= 35 && event.keyCode <= 39)) {
// let it happen, don't do anything
return;
}
else {
// Ensure that it is a number and stop the keypress
if (event.shiftKey || (event.keyCode < 48 || event.keyCode > 57) && (event.keyCode < 96 || event.keyCode > 105)) {
event.preventDefault();
}
}
});
}
};
答案 1 :(得分：8)
Knockout为此提供了扩展功能。来自knockoutjs.com的Check This解释了如何使用可观察的扩展器强制输入为数字。我粘贴了文档中的代码：
源代码：查看
<p><input data-bind="value: myNumberOne" /> (round to whole number)</p>
<p><input data-bind="value: myNumberTwo" /> (round to two decimals)</p>
源代码：查看模型
ko.extenders.numeric = function(target, precision) {
//create a writable computed observable to intercept writes to our observable
var result = ko.pureComputed({
read: target, //always return the original observables value
write: function(newValue) {
var current = target(),
roundingMultiplier = Math.pow(10, precision),
newValueAsNum = isNaN(newValue) ? 0 : parseFloat(+newValue),
valueToWrite = Math.round(newValueAsNum * roundingMultiplier) / roundingMultiplier;
//only write if it changed
if (valueToWrite !== current) {
target(valueToWrite);
} else {
//if the rounded value is the same, but a different value was written, force a notification for the current field
if (newValue !== current) {
target.notifySubscribers(valueToWrite);
}
}
}
}).extend({ notify: 'always' });
//initialize with current value to make sure it is rounded appropriately
result(target());
//return the new computed observable
return result;
};
function AppViewModel(one, two) {
this.myNumberOne = ko.observable(one).extend({ numeric: 0 });
this.myNumberTwo = ko.observable(two).extend({ numeric: 2 });
}
ko.applyBindings(new AppViewModel(221.2234, 123.4525));
答案 2 :(得分：3)
我遇到了类似的问题。
我还需要确保内部值，对于IE9及以上（所以type = numberical还不够），而且由于我们有很多国际客户，我也不能依赖密钥代码，所以以下是什么我最终得到了：
//In my js class method (self is this as usual)
self.ensureNumberical = function (data, e) {
var keyValue = e.key;
if (keyValue.match(/[0-9]/g)) {
return true;
}
return false;
}
//In my MVC View
data-bind="event: { keypress: ensureNumberical }"
答案 3 :(得分：2)
另一种方法：我发现Knockout与jQuery-validate结合使用效果很好。您只需要确保在尝试使用数值之前验证表单。
假设您有一个表单DOM元素，您可以通过
设置验证规则$(".yourform").validate({
rules: {
year: {
digits: true,
minlength: 4,
maxlength: 4
}
},
messages: {
year: "Please enter four digits (e.g. 2009).",
}
});
在您的viewmodel中，您可以像往常一样设置双向绑定，例如通过self.year = ko.observable("")。现在，请确保在进一步处理$(".yourform").valid()之前致电self.year()。就我而言，我正在做var year = parseInt(self.year(), 10)。在表单验证之后，预计会产生有意义的结果。
答案 4 :(得分：2)
最适合今天的场景https://github.com/Knockout-Contrib/Knockout-Validation
运行下面的代码段。输入非数字或超过255的内容将导致显示消息。
function model() {
var self = this;
this.myObj = ko.observable().extend({ digit: true }).extend({ max: 255});
}
var mymodel = new model();
$(document).ready(function() {
ko.validation.init();
ko.applyBindings(mymodel);
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout-validation/2.0.3/knockout.validation.min.js"></script>
enter a digit less than or equal to 255 <input type="text" data-bind="textInput: myObj">
<p>
Enter something other than a digit or over 255 will cause an error.
</p>
礼貌：Bryan Dellinger：https://stackoverflow.com/a/42940109/3868653
答案 5 :(得分：1)
<input type="text" id="alpha-validation" data-bind="value: YourDataName, valueUpdate: 'afterkeydown' , event: { 'input': AlphaCheck}" style="text-transform:uppercase">
创建AlphaCheck函数并添加它。
$('#alpha-validation').keyup(function () {
if (this.value.match(/[^0-9 ]/g)) {
this.value = this.value.replace(/[^0-9 ]/g, '');
}
});
那会有效！
答案 6 :(得分：0)
创建指向闪亮新代码的数据绑定：
<input id="price" name="price" type="text" data-bind="numeric">
闪亮的新淘汰赛代码：
price = ko.observable();
price.subscribe(function(newValue) {
price = newValue.replace(/[\D\.]/g, '');
});
这意味着每次更新价格时，它都会应用函数中的逻辑（在这种情况下，剥离不是数字或句点的任何内容），并将其直接应用于价格。您还可以在此处添加其他验证或酷炫功能，例如在开始时添加货币sybmol，将其保持在2位小数位等等...
答案 7 :(得分：0)
在“keydown”事件的帮助下，我们可以限制文本框中应该包含数值的其他键。
$(document).ready(function(){
$("selector").on("keydown", function (e) {
//numbers, delete, backspace, arrows
var validKeyCodes = [8, 9, 37, 38, 39, 40, 46, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57];
if (!($.inArray(e.keyCode, validKeyCodes) >= 0))
e.preventDefault();
});
});
答案 8 :(得分：0)
我们可以限制用户输入超过两个十进制数Ex的用户。 23.81,3452.83修改后的代码如下。参考代码取自@Martin Surynek答案。
HTML -
<p>
<input data-bind="value: myNumberOne" /> (round to whole number)</p>
<p>
<input data-bind="num, value: myNumberTwo" /> (round to two decimals)</p>
脚本 -
<script>
ko.bindingHandlers.num = {
init: function (element, valueAccessor) {
$(element).on("keypress", function (event) {
//debugger
console.log(event.keyCode);
var $this = $(this);
var text = $this.val();
// Stop insert two dots
if ($this.val().indexOf('.') != -1 && (event.which == 190 || event.which == 110)) {
event.preventDefault();
}
// Allow: backspace, delete, tab, escape, and enter
if (event.keyCode == 46 || event.keyCode == 8 || event.keyCode == 9 || event.keyCode == 27 || event.keyCode ==
13 ||
// Allow: Ctrl+A
(event.keyCode == 65 && event.ctrlKey === true) ||
// Allow: . ,event.keyCode == 188 ||
( event.keyCode == 190 || event.keyCode == 110) ||
// Allow: home, end, left, right
(event.keyCode >= 35 && event.keyCode <= 39)) {
// let it happen, don't do anything
return;
}
// Ensure that it is a number and stop the keypress
if (event.shiftKey || (event.keyCode < 48 || event.keyCode > 57) && (event.keyCode < 96 || event.keyCode >
105)) {
event.preventDefault();
}
if ((event.which == 46) && (text.indexOf('.') == -1)) {
setTimeout(function () {
if ($this.val().substring($this.val().indexOf('.')).length > 3) {
$this.val($this.val().substring(0, $this.val().indexOf('.') + 3));
}
}, 1);
}
if ((text.indexOf('.') != -1) &&
(text.substring(text.indexOf('.')).length > 2) &&
(event.which != 0 && event.which != 8) &&
($(this)[0].selectionStart >= text.length - 2)) {
event.preventDefault();
}
//console.log($(this)[0].selectionStart >= text.length - 2);
});
}
};
ko.extenders.numeric = function (target, precision) {
//create a writable computed observable to intercept writes to our observable
var result = ko.pureComputed({
read: target, //always return the original observables value
write: function (newValue) {
var current = target(),
roundingMultiplier = Math.pow(10, precision),
newValueAsNum = isNaN(newValue) ? 0 : parseFloat(+newValue),
valueToWrite = Math.round(newValueAsNum * roundingMultiplier) / roundingMultiplier;
//only write if it changed
if (valueToWrite !== current) {
target(valueToWrite);
} else {
//if the rounded value is the same, but a different value was written, force a notification for the current field
if (newValue !== current) {
target.notifySubscribers(valueToWrite);
}
}
}
}).extend({
notify: 'always'
});
//initialize with current value to make sure it is rounded appropriately
result(target());
//return the new computed observable
return result;
};
function AppViewModel(one, two) {
this.myNumberOne = ko.observable(one).extend({
numeric: 0
});
this.myNumberTwo = ko.observable(two).extend({
numeric: 2
});
}
ko.applyBindings(new AppViewModel(221.2234, 123.4525));
</script>
答案 9 :(得分：-1)
我知道这个问题已经有一年了，但是为了页面的功能访问者，让我发布这个问题。
检查出来：
ko.bindingHandlers.numericnumbers = {
init: function (element) {
$(element).on('keypress', function (number) {
number = (number) ? number : window.event;
var charcode = (number.which) ? number.which : number.keyCode;
if (charcode > 31 && (charcode < 48 || charcode > 75))
number.preventDefault();
});
}};