Knockoutjs foreach n行检查下拉列表是否有价值
Knockoutjs foreach n rows check if dropdown has value
我有这个 html 标记:
<!-- ko foreach: Orders -->
<div class="row">
<div>
<select class="form-control" data-bind="attr: { id: 'prefix_' + $index() }, options: TeacherNames, optionsValue: 'TeacherId', optionsText: 'TeacherName', optionsCaption: 'Choose Teacher', event: { change: $root.teacherChanged }">
</select>
</div>
<div>
<a href='#' data-bind="click: $root.RequestImage" class="green-btn blue pull-right">
<span class="glyphicon glyphicon-cloud-download"></span> Download
</a>
</div>
</div>
<!-- /ko -->
foreach 循环中将有 n 个项目,在开发时不会知道。
我想要做的是当 $root.RequestImage 被点击时,代码需要检查是否在该行的相关下拉列表中进行了选择,如果进行了选择则继续进行,否则显示带有 'error' 消息的警告框。
因此在 RequestImage 中应该发生该操作,这是当前的 RequestImage 函数:
self.RequestImage = function () {
};
我怎样才能做到这一点?
更新
OrdersVM:
var self = this;
self.Orders = ko.observableArray([]);
$.ajax({
type: "POST", url: "/webservices/InfoWS.asmx/GetOrders",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (data) {
if (data.d != null) {
var orderIds = [];
ko.utils.arrayForEach(data.d, function (item) {
item._teacherOrders = ko.observable();
$.ajax({
type: "POST",
url: "/webservices/InfoWS.asmx/GetTeachersForMyAccount",
contentType: "application/json; charset=utf-8",
data: "{'orderId': " + JSON.stringify(item.OrderId) + "}",
dataType: "json",
success: function (data) {
if (data) {
return item._teacherOrders(data.d);
}
},
error: function (n) {
alert('Error retrieving teachers for orders, please try again.');
}
});
item.TeacherNames = ko.computed(function () {
return item._teacherOrders();
});
self.Orders.push(item);
orderIds.push(item.OrderId);
});
}
},
error: function (data) {
var response = JSON.parse(data.responseText);
console.log("error retrieving orders:" + response.Message);
}
});
我会这样做:
- 向每个订单对象添加一个 observable
selectedTeacher
将 value: selectedTeacher
添加到您的选择中:
<select class="form-control" data-bind="attr: { id: 'prefix_' + $index() }, options: TeacherNames, optionsValue: 'TeacherId', ..., value: selectedTeacher"></select>
检查 RequestImage
事件中的可观察值
if ( !data.selectedTeacher() ) {
alert('Error: select teacher')
} else {
alert('Success')
}
一个工作演示 - Fiddle
我有这个 html 标记:
<!-- ko foreach: Orders -->
<div class="row">
<div>
<select class="form-control" data-bind="attr: { id: 'prefix_' + $index() }, options: TeacherNames, optionsValue: 'TeacherId', optionsText: 'TeacherName', optionsCaption: 'Choose Teacher', event: { change: $root.teacherChanged }">
</select>
</div>
<div>
<a href='#' data-bind="click: $root.RequestImage" class="green-btn blue pull-right">
<span class="glyphicon glyphicon-cloud-download"></span> Download
</a>
</div>
</div>
<!-- /ko -->
foreach 循环中将有 n 个项目,在开发时不会知道。
我想要做的是当 $root.RequestImage 被点击时,代码需要检查是否在该行的相关下拉列表中进行了选择,如果进行了选择则继续进行,否则显示带有 'error' 消息的警告框。
因此在 RequestImage 中应该发生该操作,这是当前的 RequestImage 函数:
self.RequestImage = function () {
};
我怎样才能做到这一点?
更新
OrdersVM:
var self = this;
self.Orders = ko.observableArray([]);
$.ajax({
type: "POST", url: "/webservices/InfoWS.asmx/GetOrders",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (data) {
if (data.d != null) {
var orderIds = [];
ko.utils.arrayForEach(data.d, function (item) {
item._teacherOrders = ko.observable();
$.ajax({
type: "POST",
url: "/webservices/InfoWS.asmx/GetTeachersForMyAccount",
contentType: "application/json; charset=utf-8",
data: "{'orderId': " + JSON.stringify(item.OrderId) + "}",
dataType: "json",
success: function (data) {
if (data) {
return item._teacherOrders(data.d);
}
},
error: function (n) {
alert('Error retrieving teachers for orders, please try again.');
}
});
item.TeacherNames = ko.computed(function () {
return item._teacherOrders();
});
self.Orders.push(item);
orderIds.push(item.OrderId);
});
}
},
error: function (data) {
var response = JSON.parse(data.responseText);
console.log("error retrieving orders:" + response.Message);
}
});
我会这样做:
- 向每个订单对象添加一个 observable
selectedTeacher
将
value: selectedTeacher
添加到您的选择中:<select class="form-control" data-bind="attr: { id: 'prefix_' + $index() }, options: TeacherNames, optionsValue: 'TeacherId', ..., value: selectedTeacher"></select>
检查
RequestImage
事件中的可观察值if ( !data.selectedTeacher() ) { alert('Error: select teacher') } else { alert('Success') }
一个工作演示 - Fiddle