Knockout (或者Knockout.js
，KnockoutJS)是一个开源的JavaScript库，网址为www.knockoutjs.com。Knockout语法简洁、可读性好，能轻松实现与DOM元素的关联。一旦数据模型的状态发生改变，则立即自动刷新UI。Knockout采用Model-View-View-Model
(MVVM)的设计模式来简化动态JavaScript UI。Knockout有效实现了JavaScript与UI
HTML呈现的分离。有了Knockout，在写JavaScript时，就不需要在页面中引用UI元素或DOM。
，KnockoutJS)是一个开源的JavaScript库，网址为www.knockoutjs.com。Knockout语法简洁、可读性好，能轻松实现与DOM元素的关联。一旦数据模型的状态发生改变，则立即自动刷新UI。Knockout采用Model-View-View-Model
(MVVM)的设计模式来简化动态JavaScript UI。Knockout有效实现了JavaScript与UI
HTML呈现的分离。有了Knockout，在写JavaScript时，就不需要在页面中引用UI元素或DOM。
Knockout设计目标是把任何JavaScript对象当成View Model来使用。只要View
Model的属性具有可监听性，就可以使用Knockout将其与UI绑定。一旦属性值发生变化时，UI会被自动刷新。
Order Entry Header – 编辑模式与显示模式
Order Header页面的关键功能是，在不重复提交整个页面的前提下，自由切换编辑模式与显示模式。ASP.NET
post-back模式通常表现为：用户点击Edit按钮，post提交至服务器，返回后，整个页面被重新刷新。使用Knockout与MVVM数据绑定技术，则可以避免页面重新刷新。这里，我们需要做的仅仅是将Order
Header页面去绑定JavaScript创建的View Model。
数据绑定标签
为创建一个MVC View来回切换只读与编辑模式，我们为页面的每一个元素都创建单独的DIV与SPAN标签。一个(编辑模式)包含INPUT
HTML控件，另一个(只读)只显示文本。添加Knockout数据绑定标签可以灵活控制HTML元素何时被显示，何时被隐藏。下例中，ShipName
包含一个两个数据绑定标签，前者关联Ship Name的值，后者是一个布尔标签，控制只读或编辑模式。
<div
style="float:left;
width:150px; height:25px; text-align:right;"
class="field-label">Ship To Name:
</div>
<div style="float:left; width:300px; height:25px;">
<span data-bind="visible:EditFields">
@Html.TextBox("ShipName",
@Model.Order.ShipName, new Dictionary<string, object> {
{
"data-bind", "value:
ShipName" }, { "style", "width:300px" } })
</span>
<span data-bind="visible: ReadOnlyMode, text: OriginalShipName"></span>
</div>
style="float:left;
width:150px; height:25px; text-align:right;"
class="field-label">Ship To Name:
</div>
<div style="float:left; width:300px; height:25px;">
<span data-bind="visible:EditFields">
@Html.TextBox("ShipName",
@Model.Order.ShipName, new Dictionary<string, object> {
{
"data-bind", "value:
ShipName" }, { "style", "width:300px" } })
</span>
<span data-bind="visible: ReadOnlyMode, text: OriginalShipName"></span>
</div>
Order Entry显示模式
当第一次选择一个Order编辑时，此时页面处于只读模式。要创建Knockout与HTML对象的自动绑定，我们必须创建一个JavaScript View
Model对象，与Knockout绑定，这样Knockout可以监听View Model对象属性的变化，并自动更新UI。
// Overall viewmodel
for this
screen, along with initial state
var viewModel =
{
EditFields: ko.observable(false),
ReadOnlyMode: ko.observable(false),
DisplayCreateOrderButton:
ko.observable(false),
DisplayEditOrderButton:
ko.observable(false),
DisplayUpdateOrderButton:
ko.observable(false),
DisplayOrderDetailsButton:
ko.observable(false),
DisplayCancelChangesButton:
ko.observable(true),
SelectedShipVia: ko.observable($("#OriginalShipVia").val()),
Shippers:
ko.observableArray(shippers),
OrderID: ko.observable($("#OrderID").val()),
ShipperName:
ko.observable($("#ShipperName").val()),
CustomerID:
ko.observable($("#CustomerID").val()),
OriginalShipName:
ko.observable($("#OriginalShipName").val()),
OriginalShipAddress:
ko.observable($("#OriginalShipAddress").val()),
OriginalShipCity:
ko.observable($("#OriginalShipCity").val()),
OriginalShipRegion:
ko.observable($("#OriginalShipRegion").val()),
OriginalShipPostalCode:
ko.observable($("#OriginalShipPostalCode").val()),
OriginalShipCountry:
ko.observable($("#OriginalShipCountry").val()),
OriginalRequiredDate:
ko.observable($("#OriginalRequiredDate").val()),
OriginalShipVia:
ko.observable($("#OriginalShipVia").val()),
ShipName: ko.observable($("#OriginalShipName").val()),
ShipAddress:
ko.observable($("#OriginalShipAddress").val()),
ShipCity: ko.observable($("#OriginalShipCity").val()),
ShipRegion:
ko.observable($("#OriginalShipRegion").val()),
ShipPostalCode:
ko.observable($("#OriginalShipPostalCode").val()),
ShipCountry:
ko.observable($("#OriginalShipCountry").val()),
RequiredDate:
ko.observable($("#OriginalRequiredDate").val()),
MessageBox: ko.observable("")
}
ko.applyBindings(viewModel);
for this
screen, along with initial state
var viewModel =
{
EditFields: ko.observable(false),
ReadOnlyMode: ko.observable(false),
DisplayCreateOrderButton:
ko.observable(false),
DisplayEditOrderButton:
ko.observable(false),
DisplayUpdateOrderButton:
ko.observable(false),
DisplayOrderDetailsButton:
ko.observable(false),
DisplayCancelChangesButton:
ko.observable(true),
SelectedShipVia: ko.observable($("#OriginalShipVia").val()),
Shippers:
ko.observableArray(shippers),
OrderID: ko.observable($("#OrderID").val()),
ShipperName:
ko.observable($("#ShipperName").val()),
CustomerID:
ko.observable($("#CustomerID").val()),
OriginalShipName:
ko.observable($("#OriginalShipName").val()),
OriginalShipAddress:
ko.observable($("#OriginalShipAddress").val()),
OriginalShipCity:
ko.observable($("#OriginalShipCity").val()),
OriginalShipRegion:
ko.observable($("#OriginalShipRegion").val()),
OriginalShipPostalCode:
ko.observable($("#OriginalShipPostalCode").val()),
OriginalShipCountry:
ko.observable($("#OriginalShipCountry").val()),
OriginalRequiredDate:
ko.observable($("#OriginalRequiredDate").val()),
OriginalShipVia:
ko.observable($("#OriginalShipVia").val()),
ShipName: ko.observable($("#OriginalShipName").val()),
ShipAddress:
ko.observable($("#OriginalShipAddress").val()),
ShipCity: ko.observable($("#OriginalShipCity").val()),
ShipRegion:
ko.observable($("#OriginalShipRegion").val()),
ShipPostalCode:
ko.observable($("#OriginalShipPostalCode").val()),
ShipCountry:
ko.observable($("#OriginalShipCountry").val()),
RequiredDate:
ko.observable($("#OriginalRequiredDate").val()),
MessageBox: ko.observable("")
}
ko.applyBindings(viewModel);
我们创建一个Edit Order点击事件函数，当用户点击Edit Order按钮，页面处于编辑模式。代码如下：
$("#btnEditOrder").click(function ()
{
viewModel.DisplayEditOrderButton(false);
viewModel.DisplayUpdateOrderButton(true);
viewModel.DisplayOrderDetailsButton(false);
viewModel.DisplayCancelChangesButton(true);
viewModel.EditFields(true);
viewModel.ReadOnlyMode(false);
});
{
viewModel.DisplayEditOrderButton(false);
viewModel.DisplayUpdateOrderButton(true);
viewModel.DisplayOrderDetailsButton(false);
viewModel.DisplayCancelChangesButton(true);
viewModel.EditFields(true);
viewModel.ReadOnlyMode(false);
});
上例中，我们使用Unobtrusive
JavaScript这种方式来触发Edit按钮点击事件，实现两种显示与编辑模式的切换。Knockout会监听View
Model，实现自动切换。Unobtrusive JavaScript是一项用于页面内容结构与页面呈现分离的新技术。
用户点击Update Oder 按钮，则调用UpdateOrder 函数。UpdateOrder 函数的功能是抓取View
Model的值，并创建一个表示物流信息的JavaScript对象。通过JQuery
AJAX调用，该对象将提交给UpdateOrderController函数。
function
UpdateOrder() {
var shippingInformation = new
ShippingInformation();
shippingInformation.OrderID =
viewModel.OrderID();
shippingInformation.CustomerID =
viewModel.CustomerID();
shippingInformation.ShipName =
viewModel.ShipName();
shippingInformation.ShipAddress =
viewModel.ShipAddress();
shippingInformation.ShipCity =
viewModel.ShipCity();
shippingInformation.ShipRegion =
viewModel.ShipRegion();
shippingInformation.ShipPostalCode =
viewModel.ShipPostalCode();
shippingInformation.ShipCountry
=
viewModel.ShipCountry();
shippingInformation.RequiredDate =
viewModel.RequiredDate();
shippingInformation.Shipper =
viewModel.SelectedShipVia();
var url = "/Orders/UpdateOrder";
$(':input').removeClass('validation-error');
$.post(url,
shippingInformation, function (data, textStatus)
{
UpdateOrderComplete(data);
});
}
function
UpdateOrderComplete(result) {
if
(result.ReturnStatus == true)
{
viewModel.MessageBox(result.MessageBoxView);
viewModel.OrderID(result.ViewModel.Order.OrderID);
viewModel.ShipperName(result.ViewModel.Order.ShipperName);
viewModel.DisplayEditOrderButton(true);
viewModel.DisplayUpdateOrderButton(false);
viewModel.DisplayOrderDetailsButton(true);
viewModel.DisplayCancelChangesButton(false);
viewModel.DisplayCreateOrderButton(false);
viewModel.EditFields(false);
viewModel.ReadOnlyMode(true);
viewModel.OriginalShipName(result.ViewModel.Order.ShipName);
viewModel.OriginalShipAddress(result.ViewModel.Order.ShipAddress);
viewModel.OriginalShipCity(result.ViewModel.Order.ShipCity);
viewModel.OriginalShipRegion(result.ViewModel.Order.ShipRegion);
viewModel.OriginalShipPostalCode(result.ViewModel.Order.ShipPostalCode);
viewModel.OriginalShipCountry(result.ViewModel.Order.ShipCountry);
viewModel.OriginalRequiredDate(result.ViewModel.Order.RequiredDateFormatted);
viewModel.OriginalShipVia(viewModel.SelectedShipVia());
}
else
{
viewModel.MessageBox(result.MessageBoxView);
}
for (var val in
result.ValidationErrors) {
var element = "#" +
val;
$(element).addClass('validation-error');
}
}
UpdateOrder() {
var shippingInformation = new
ShippingInformation();
shippingInformation.OrderID =
viewModel.OrderID();
shippingInformation.CustomerID =
viewModel.CustomerID();
shippingInformation.ShipName =
viewModel.ShipName();
shippingInformation.ShipAddress =
viewModel.ShipAddress();
shippingInformation.ShipCity =
viewModel.ShipCity();
shippingInformation.ShipRegion =
viewModel.ShipRegion();
shippingInformation.ShipPostalCode =
viewModel.ShipPostalCode();
shippingInformation.ShipCountry
=
viewModel.ShipCountry();
shippingInformation.RequiredDate =
viewModel.RequiredDate();
shippingInformation.Shipper =
viewModel.SelectedShipVia();
var url = "/Orders/UpdateOrder";
$(':input').removeClass('validation-error');
$.post(url,
shippingInformation, function (data, textStatus)
{
UpdateOrderComplete(data);
});
}
function
UpdateOrderComplete(result) {
if
(result.ReturnStatus == true)
{
viewModel.MessageBox(result.MessageBoxView);
viewModel.OrderID(result.ViewModel.Order.OrderID);
viewModel.ShipperName(result.ViewModel.Order.ShipperName);
viewModel.DisplayEditOrderButton(true);
viewModel.DisplayUpdateOrderButton(false);
viewModel.DisplayOrderDetailsButton(true);
viewModel.DisplayCancelChangesButton(false);
viewModel.DisplayCreateOrderButton(false);
viewModel.EditFields(false);
viewModel.ReadOnlyMode(true);
viewModel.OriginalShipName(result.ViewModel.Order.ShipName);
viewModel.OriginalShipAddress(result.ViewModel.Order.ShipAddress);
viewModel.OriginalShipCity(result.ViewModel.Order.ShipCity);
viewModel.OriginalShipRegion(result.ViewModel.Order.ShipRegion);
viewModel.OriginalShipPostalCode(result.ViewModel.Order.ShipPostalCode);
viewModel.OriginalShipCountry(result.ViewModel.Order.ShipCountry);
viewModel.OriginalRequiredDate(result.ViewModel.Order.RequiredDateFormatted);
viewModel.OriginalShipVia(viewModel.SelectedShipVia());
}
else
{
viewModel.MessageBox(result.MessageBoxView);
}
for (var val in
result.ValidationErrors) {
var element = "#" +
val;
$(element).addClass('validation-error');
}
}
验证错误
我们可通过一个CSS类以显示验证错误信息。CSS会循环遍历JSON返回的INPUT控件对象，验证其输入值是否合法如有错误则用红色标记高亮。代码如下：
for (var val in
result.ValidationErrors) {
var element = "#" +
val;
$(element).addClass('validation-error');
}
result.ValidationErrors) {
var element = "#" +
val;
$(element).addClass('validation-error');
}
Oder Entry Details视图 – Knockout 模版
在完成Order Shipping Information的编辑之后，用户可查看订单详细列表，并可向订单中添加产品。下面的Order Details
View使用Knockout模版功能，实现了无需post–back的前提下，逐行编辑每一个line item。
Knockout 模版可轻松实现复杂的UI，例如不断重复与嵌套的Block。Knockout模版将模版渲染之结果填充至关联的DOM元素。
预渲染与格式化数据
通常情况下，数据在前后端的结构与模式所有不同，特别是对于日期，货币等字段，此时就免不了数据的重新格式化。在传统的ASP.NET
Web表单中，多数控件是通过预渲染或数据绑定事件，来实现数据到达给用户之前的重新格式化。在MVC中，我们可以抓取View Model数据，调用服务器端代码，实现在View开始阶段做预渲染操作。下例中，拿到重新格式化的数据后，我们生成了一个订单明细列表。
@model
NorthwindViewModel.OrderViewModel
@{
ViewBag.Title
=
"Order
Entry Detail";
ArrayList orderDetails = new
ArrayList();
foreach (var item in
Model.OrderDetailsProducts)
{
var orderDetail = new
{
ProductID =
item.OrderDetails.ProductIDFormatted,
ProductName =
item.Products.ProductName,
Quantity =
item.OrderDetails.Quantity,
UnitPrice =
item.OrderDetails.UnitPriceFormatted,
QuantityPerUnit =
item.Products.QuantityPerUnit,
Discount =
item.OrderDetails.DiscountFormatted
};
orderDetails.Add(orderDetail);
}
}
NorthwindViewModel.OrderViewModel
@{
ViewBag.Title
=
"Order
Entry Detail";
ArrayList orderDetails = new
ArrayList();
foreach (var item in
Model.OrderDetailsProducts)
{
var orderDetail = new
{
ProductID =
item.OrderDetails.ProductIDFormatted,
ProductName =
item.Products.ProductName,
Quantity =
item.OrderDetails.Quantity,
UnitPrice =
item.OrderDetails.UnitPriceFormatted,
QuantityPerUnit =
item.Products.QuantityPerUnit,
Discount =
item.OrderDetails.DiscountFormatted
};
orderDetails.Add(orderDetail);
}
}
待数据完成格式化后，我们使用DIV标签加载编码后的JSON对象。稍后，JavaScript将访问该JSON对象，将数据绑定至knockout模版。
我们创建一个Knockout模版，如下。Script标签的类型为text/html，包含各种内容与数据绑定标签。
<!--====== Template
======-->
<script
type="text/html" id="OrderDetailTemplate">
<tr data-bind="style: { background:
viewModel.SetBackgroundColor($data) }">
<td style="height:25px"><div data-bind="text:ProductID"></div></td>
<td><div
data-bind="text:
ProductName"></div></td>
<td>
<div data-bind="text: Quantity,
visible:DisplayMode "></div>
<div data-bind="visible:
EditMode" >
<input type="text" data-bind="value:
Quantity" style="width:
50px"
/>
</div>
</td>
<td><div
data-bind="text:UnitPrice"></div></td>
<td><div
data-bind="text:
QuantityPerUnit"></div></td>
<td><div
data-bind="text: Discount,
visible:DisplayMode "></div>
<div data-bind="visible:
EditMode" >
<input type="text" data-bind="value:Discount" style="width:50px" />
</div>
</td>
<td>
<div
data-bind="visible:DisplayDeleteEditButtons">
<div style="width:25px;float:left"><img alt="delete" data-bind="click:function()
{
viewModel.DeleteLineItem($data) }"
title="Delete item" src="@Url.Content("~/Content/Images/icon-delete.gif")"/>
</div>
<div style="width:25px;float:left"><img alt="edit" data-bind="click:function()
{
viewModel.EditLineItem($data) }" title="Edit item"
src="@Url.Content("~/Content/Images/icon-pencil.gif")"/>
</div>
</div>
<div data-bind="visible:DisplayCancelSaveButtons">
<div style="width:25px;float:left"><img alt="save" data-bind="click: function()
{viewModel.UpdateLineItem($data) }" title="Save
item"
src="@Url.Content("~/Content/Images/icon-floppy.gif")"/>
</div>
<div style="width:25px;float:left"><img alt="cancel
edit"
data-bind="click:function() {
viewModel.CancelLineItem($data) }"
title="Cancel
Edit"
src="@Url.Content("~/Content/Images/icon-pencil-x.gif")"/>
</div>
</div>
</td>
</tr>
</script>
======-->
<script
type="text/html" id="OrderDetailTemplate">
<tr data-bind="style: { background:
viewModel.SetBackgroundColor($data) }">
<td style="height:25px"><div data-bind="text:ProductID"></div></td>
<td><div
data-bind="text:
ProductName"></div></td>
<td>
<div data-bind="text: Quantity,
visible:DisplayMode "></div>
<div data-bind="visible:
EditMode" >
<input type="text" data-bind="value:
Quantity" style="width:
50px"
/>
</div>
</td>
<td><div
data-bind="text:UnitPrice"></div></td>
<td><div
data-bind="text:
QuantityPerUnit"></div></td>
<td><div
data-bind="text: Discount,
visible:DisplayMode "></div>
<div data-bind="visible:
EditMode" >
<input type="text" data-bind="value:Discount" style="width:50px" />
</div>
</td>
<td>
<div
data-bind="visible:DisplayDeleteEditButtons">
<div style="width:25px;float:left"><img alt="delete" data-bind="click:function()
{
viewModel.DeleteLineItem($data) }"
title="Delete item" src="@Url.Content("~/Content/Images/icon-delete.gif")"/>
</div>
<div style="width:25px;float:left"><img alt="edit" data-bind="click:function()
{
viewModel.EditLineItem($data) }" title="Edit item"
src="@Url.Content("~/Content/Images/icon-pencil.gif")"/>
</div>
</div>
<div data-bind="visible:DisplayCancelSaveButtons">
<div style="width:25px;float:left"><img alt="save" data-bind="click: function()
{viewModel.UpdateLineItem($data) }" title="Save
item"
src="@Url.Content("~/Content/Images/icon-floppy.gif")"/>
</div>
<div style="width:25px;float:left"><img alt="cancel
edit"
data-bind="click:function() {
viewModel.CancelLineItem($data) }"
title="Cancel
Edit"
src="@Url.Content("~/Content/Images/icon-pencil-x.gif")"/>
</div>
</div>
</td>
</tr>
</script>
要想将Knockout模版添加至HTML中，只需要使用data-bind模版标签与一个foreach语句即可。
<!--====== Container
======-->
<table border="0" cellpadding="0" cellspacing="0" style="width:100%">
<tr class="DataGridHeader">
<td style="width:10%;
height:25px">Product
ID</td>
<td style="width:30%">Product Description</td>
<td
style="width:10%">Quantity</td>
<td
style="width:10%">Unit Price</td>
<td
style="width:15%">UOM</td>
<td style="width:10%">Discount</td>
<td
style="width:15%">Edit Options</td>
</tr>
<tbody
data-bind='template: {name:
"OrderDetailTemplate", foreach:LineItems}'> </tbody>
</table>
======-->
<table border="0" cellpadding="0" cellspacing="0" style="width:100%">
<tr class="DataGridHeader">
<td style="width:10%;
height:25px">Product
ID</td>
<td style="width:30%">Product Description</td>
<td
style="width:10%">Quantity</td>
<td
style="width:10%">Unit Price</td>
<td
style="width:15%">UOM</td>
<td style="width:10%">Discount</td>
<td
style="width:15%">Edit Options</td>
</tr>
<tbody
data-bind='template: {name:
"OrderDetailTemplate", foreach:LineItems}'> </tbody>
</table>
JavaScript eval函数可作JSON对象的解析。不过，由于JavaScript
eval可编译并运行任何JavaScript程序，会导致安全性问题。因此，较安全的做法是使用JSON解析器。JSON解析器只识别JSON文本，而不会执行任何潜在风险的脚本。json.org网站中提供了许多JavaScript编写的JSON解析器。
使用JSON解析器，我们可以解析初始加载的订单明细数据，这些数据会与Knockout View Model实现绑定。当创建多个details line
items时，我们需要创建一个数组，供Knockout监听。
Knockout映射插件
上例中，我们采取的是自定义创建View
Model的方式。另一种方式是采用Knockout映射插件，选择合适的映射规则，直截了将JavaScript对象与View Model绑定。
编辑，更新与删除Template Items
完整的页面Knockout View Model包含有line item的编辑，更新，删除。
<script
language="javascript" type="text/javascript">
var viewModel = {
LineItems:
ko.observableArray(),
MessageBox: ko.observable(),
AddNewLineItem:
ko.observable(false),
SetBackgroundColor: function
(currentLineItemData) {
var rowIndex =
this.LineItems.indexOf(currentLineItemData);
var colorCode = rowIndex %
2
==
0 ?
"White" : "WhiteSmoke";
return
colorCode;
},
EditLineItem: function
(currentLineItemData) {
var currentLineItem =
this.LineItems.indexOf(currentLineItemData);
this.LineItems()[currentLineItem].DisplayMode(false);
this.LineItems()[currentLineItem].EditMode(true);
this.LineItems()[currentLineItem].DisplayDeleteEditButtons(false);
this.LineItems()[currentLineItem].DisplayCancelSaveButtons(true);
},
DeleteLineItem: function (currentLineItemData) {
var currentLineItem
=
this.LineItems.indexOf(currentLineItemData);
var productName =
this.LineItems()[currentLineItem].ProductName();
var productID =
this.LineItems()[currentLineItem].ProductID();
ConfirmDeleteLineItem(productID, productName, currentLineItem);
},
DeleteLineItemConfirmed: function
(currentLineItem) {
var row = this.LineItems()[currentLineItem];
this.LineItems.remove(row);
},
CancelLineItem: function
(currentLineItemData) {
currentLineItem =
this.LineItems.indexOf(currentLineItemData);
this.LineItems()[currentLineItem].DisplayMode(true);
this.LineItems()[currentLineItem].EditMode(false);
this.LineItems()[currentLineItem].DisplayDeleteEditButtons(true);
this.LineItems()[currentLineItem].DisplayCancelSaveButtons(false);
this.LineItems()[currentLineItem].Quantity(this.LineItems()
[currentLineItem].OriginalQuantity());
this.LineItems()[currentLineItem].Discount(this.LineItems()
[currentLineItem].OriginalDiscount());
},
UpdateLineItem: function (currentLineItemData) {
currentLineItem
=
this.LineItems.indexOf(currentLineItemData);
var lineItem =
this.LineItems()[currentLineItem];
UpdateOrderDetail(lineItem,
currentLineItem);
},
UpdateOrderDetailComplete: function
(currentLineItem, discount)
{
this.LineItems()[currentLineItem].DisplayMode(true);
this.LineItems()[currentLineItem].EditMode(false);
this.LineItems()[currentLineItem].DisplayDeleteEditButtons(true);
this.LineItems()[currentLineItem].DisplayCancelSaveButtons(false);
this.LineItems()[currentLineItem].OriginalQuantity(this.LineItems()
[currentLineItem].Quantity());
this.LineItems()[currentLineItem].OriginalDiscount(discount);
this.LineItems()[currentLineItem].Discount(discount);
}
}
language="javascript" type="text/javascript">
var viewModel = {
LineItems:
ko.observableArray(),
MessageBox: ko.observable(),
AddNewLineItem:
ko.observable(false),
SetBackgroundColor: function
(currentLineItemData) {
var rowIndex =
this.LineItems.indexOf(currentLineItemData);
var colorCode = rowIndex %
2
==
0 ?
"White" : "WhiteSmoke";
return
colorCode;
},
EditLineItem: function
(currentLineItemData) {
var currentLineItem =
this.LineItems.indexOf(currentLineItemData);
this.LineItems()[currentLineItem].DisplayMode(false);
this.LineItems()[currentLineItem].EditMode(true);
this.LineItems()[currentLineItem].DisplayDeleteEditButtons(false);
this.LineItems()[currentLineItem].DisplayCancelSaveButtons(true);
},
DeleteLineItem: function (currentLineItemData) {
var currentLineItem
=
this.LineItems.indexOf(currentLineItemData);
var productName =
this.LineItems()[currentLineItem].ProductName();
var productID =
this.LineItems()[currentLineItem].ProductID();
ConfirmDeleteLineItem(productID, productName, currentLineItem);
},
DeleteLineItemConfirmed: function
(currentLineItem) {
var row = this.LineItems()[currentLineItem];
this.LineItems.remove(row);
},
CancelLineItem: function
(currentLineItemData) {
currentLineItem =
this.LineItems.indexOf(currentLineItemData);
this.LineItems()[currentLineItem].DisplayMode(true);
this.LineItems()[currentLineItem].EditMode(false);
this.LineItems()[currentLineItem].DisplayDeleteEditButtons(true);
this.LineItems()[currentLineItem].DisplayCancelSaveButtons(false);
this.LineItems()[currentLineItem].Quantity(this.LineItems()
[currentLineItem].OriginalQuantity());
this.LineItems()[currentLineItem].Discount(this.LineItems()
[currentLineItem].OriginalDiscount());
},
UpdateLineItem: function (currentLineItemData) {
currentLineItem
=
this.LineItems.indexOf(currentLineItemData);
var lineItem =
this.LineItems()[currentLineItem];
UpdateOrderDetail(lineItem,
currentLineItem);
},
UpdateOrderDetailComplete: function
(currentLineItem, discount)
{
this.LineItems()[currentLineItem].DisplayMode(true);
this.LineItems()[currentLineItem].EditMode(false);
this.LineItems()[currentLineItem].DisplayDeleteEditButtons(true);
this.LineItems()[currentLineItem].DisplayCancelSaveButtons(false);
this.LineItems()[currentLineItem].OriginalQuantity(this.LineItems()
[currentLineItem].Quantity());
this.LineItems()[currentLineItem].OriginalDiscount(discount);
this.LineItems()[currentLineItem].Discount(discount);
}
}
选择一个line item，点击铅笔编辑图标，EditLineItem函数会触发onclick事件，line item处于编辑模式。如下：
EditLineItem: function
(currentLineItemData) {
var currentLineItem =
this.LineItems.indexOf(currentLineItemData);
this.LineItems()[currentLineItem].DisplayMode(false);
this.LineItems()[currentLineItem].EditMode(true);
this.LineItems()[currentLineItem].DisplayDeleteEditButtons(false);
this.LineItems()[currentLineItem].DisplayCancelSaveButtons(true);
},
(currentLineItemData) {
var currentLineItem =
this.LineItems.indexOf(currentLineItemData);
this.LineItems()[currentLineItem].DisplayMode(false);
this.LineItems()[currentLineItem].EditMode(true);
this.LineItems()[currentLineItem].DisplayDeleteEditButtons(false);
this.LineItems()[currentLineItem].DisplayCancelSaveButtons(true);
},
借助Knockout模版与Knockout绑定技术，我们可以创建类似ASP.NET Web Forms
DataGrid控件的完整in-line编辑grid。
点击Add Line Item按钮，打开一个line
item，可将一个item添加至order中。
使用modal popup窗口，可搜索一个Product Item。在一个新的line item上点击Search按钮，弹出product
search 窗口。
The Modal Popup Product Search 窗口
Modal 弹出窗口是AJAX调用与Partial View的结合。AJAX 请求调用Product Inquiry
partial view，返回product search的内容，最后填充至DIV标签。
<div
id="dialog-modal" title="Product Inquiry">
<div id="ProductInquiryModalDiv"> </div>
</div>
id="dialog-modal" title="Product Inquiry">
<div id="ProductInquiryModalDiv"> </div>
</div>
Modal 弹出窗口是一个具有dialog功能的JQuery插件。
function
ShowProductInquiryModal() {
var url = "/Products/BeginProductInquiry";
$.post(url,
null,
function
(html, textStatus) {
ShowProductInquiryModalComplete(html);
});
}
function ShowProductInquiryModalComplete(productInquiryHtml)
{
$("#ProductInquiryModalDiv").html(productInquiryHtml);
$("#dialog-modal").dialog({
height: 500,
width: 900,
modal:
true
});
//
// execute Product Inquiry query after the initial page content has
been loaded
//
setTimeout("ProductInquiryInitializeGrid()", 1000);
}
ShowProductInquiryModal() {
var url = "/Products/BeginProductInquiry";
$.post(url,
null,
function
(html, textStatus) {
ShowProductInquiryModalComplete(html);
});
}
function ShowProductInquiryModalComplete(productInquiryHtml)
{
$("#ProductInquiryModalDiv").html(productInquiryHtml);
$("#dialog-modal").dialog({
height: 500,
width: 900,
modal:
true
});
//
// execute Product Inquiry query after the initial page content has
been loaded
//
setTimeout("ProductInquiryInitializeGrid()", 1000);
}
Product Inquiry Search窗口 – UID生成机制
Product Inquiry Search窗口本身是一个Partial View。由于该窗口与Order
Order页面加载的DOM一样，因此所有的HTML控件与动态创建的JavaScript函数及变量均要求名字独一无二。在渲染页面内容之前，该Partial
View实例化自定义的PageIDGeneration类，调用GenerateID方法，生成独一无二的控件ID，JavaScript函数名，以及变量名。PageIDGeneration类通过设置unique
Guid数目，保证生成ID的唯一性。
@model NorthwindViewModel.ProductViewModel
@using
NorthwindWebApplication.Helpers;
@{
NorthwindWebControls.PageIDGeneration webControls =
new
NorthwindWebControls.PageIDGeneration();
string txtProductID
=
webControls.GenerateID("ProductID");
string
txtProductDescription = webControls.GenerateID("ProductName");
string btnSearch
=
webControls.GenerateID("BtnSearch");
string btnReset
=
webControls.GenerateID("BtnReset");
string messageBox
=
webControls.GenerateID("MessageBox");
string productResults
=
webControls.GenerateID("ProductResults");
}
<div class="SearchBar">
<div style="float:left; width:200px">
Product ID
</div>
<div
style="float:left;
width:200px">
Product
Description
</div>
<div style="clear:both;"></div>
<div style="float:left; width:200px">
<input id="@txtProductID" type="text" value="" style = "width:150px" />
</div>
<div style="float:left; width:200px ">
<input id="@txtProductDescription" type="text" value="" style = "width:150px" />
</div>
<input id="@btnSearch" type="button" value="Search" />
<input id="@btnReset" type="button" value="Reset"/>
</div>
<div
style="clear:both;"></div>
<div id="@productResults"></div>
<div id="@messageBox"></div>
@Html.RenderJavascript(webControls.RenderJavascriptVariables("ProductInquiry_"))
<script
language="javascript" type="text/javascript">
$(ProductInquiry_BtnSearch).click(function() {
ProductInquiryInitializeGrid();
});
$(ProductInquiry_BtnReset).click(function()
{
$(ProductInquiry_ProductID).val("");
$(ProductInquiry_ProductName).val("");
ProductInquiryInitializeGrid();
});
function ProductInquiryRequest() {
this.CurrentPageNumber;
this.PageSize;
this.ProductID;
this.ProductName;
this.SortDirection;
this.SortExpression;
this.PageID;
};
function ProductInquiry(currentPageNumber, sortExpression,
sortDirection) {
var url = "/Products/ProductInquiry";
var
productInquiryRequest = new ProductInquiryRequest();
productInquiryRequest.ProductID =
$(ProductInquiry_ProductID).val();
productInquiryRequest.ProductName
=
$(ProductInquiry_ProductName).val();
productInquiryRequest.CurrentPageNumber
=
currentPageNumber;
productInquiryRequest.SortDirection = sortDirection;
productInquiryRequest.SortExpression = sortExpression;
productInquiryRequest.PageSize = 10;
productInquiryRequest.PageID =
$(ProductInquiry_PageID).val();
$.post(url, productInquiryRequest,
function
(data, textStatus) {
ProductInquiryComplete(data);
});
};
function ProductInquiryComplete(result) {
if
(result.ReturnStatus == true) {
$(ProductInquiry_ProductResults).html("");
$(ProductInquiry_ProductResults).html(result.ProductInquiryView);
$(ProductInquiry_MessageBox).html("");
}
else
{
$(ProductInquiry_MessageBox).html(result.MessageBoxView);
}
}
function ProductInquiryInitializeGrid()
{
ProductInquiry(1, "ProductName", "ASC");
}
function ProductSelected(productID)
{
GetProductInformation(productID);
}
</script>
@using
NorthwindWebApplication.Helpers;
@{
NorthwindWebControls.PageIDGeneration webControls =
new
NorthwindWebControls.PageIDGeneration();
string txtProductID
=
webControls.GenerateID("ProductID");
string
txtProductDescription = webControls.GenerateID("ProductName");
string btnSearch
=
webControls.GenerateID("BtnSearch");
string btnReset
=
webControls.GenerateID("BtnReset");
string messageBox
=
webControls.GenerateID("MessageBox");
string productResults
=
webControls.GenerateID("ProductResults");
}
<div class="SearchBar">
<div style="float:left; width:200px">
Product ID
</div>
<div
style="float:left;
width:200px">
Product
Description
</div>
<div style="clear:both;"></div>
<div style="float:left; width:200px">
<input id="@txtProductID" type="text" value="" style = "width:150px" />
</div>
<div style="float:left; width:200px ">
<input id="@txtProductDescription" type="text" value="" style = "width:150px" />
</div>
<input id="@btnSearch" type="button" value="Search" />
<input id="@btnReset" type="button" value="Reset"/>
</div>
<div
style="clear:both;"></div>
<div id="@productResults"></div>
<div id="@messageBox"></div>
@Html.RenderJavascript(webControls.RenderJavascriptVariables("ProductInquiry_"))
<script
language="javascript" type="text/javascript">
$(ProductInquiry_BtnSearch).click(function() {
ProductInquiryInitializeGrid();
});
$(ProductInquiry_BtnReset).click(function()
{
$(ProductInquiry_ProductID).val("");
$(ProductInquiry_ProductName).val("");
ProductInquiryInitializeGrid();
});
function ProductInquiryRequest() {
this.CurrentPageNumber;
this.PageSize;
this.ProductID;
this.ProductName;
this.SortDirection;
this.SortExpression;
this.PageID;
};
function ProductInquiry(currentPageNumber, sortExpression,
sortDirection) {
var url = "/Products/ProductInquiry";
var
productInquiryRequest = new ProductInquiryRequest();
productInquiryRequest.ProductID =
$(ProductInquiry_ProductID).val();
productInquiryRequest.ProductName
=
$(ProductInquiry_ProductName).val();
productInquiryRequest.CurrentPageNumber
=
currentPageNumber;
productInquiryRequest.SortDirection = sortDirection;
productInquiryRequest.SortExpression = sortExpression;
productInquiryRequest.PageSize = 10;
productInquiryRequest.PageID =
$(ProductInquiry_PageID).val();
$.post(url, productInquiryRequest,
function
(data, textStatus) {
ProductInquiryComplete(data);
});
};
function ProductInquiryComplete(result) {
if
(result.ReturnStatus == true) {
$(ProductInquiry_ProductResults).html("");
$(ProductInquiry_ProductResults).html(result.ProductInquiryView);
$(ProductInquiry_MessageBox).html("");
}
else
{
$(ProductInquiry_MessageBox).html(result.MessageBoxView);
}
}
function ProductInquiryInitializeGrid()
{
ProductInquiry(1, "ProductName", "ASC");
}
function ProductSelected(productID)
{
GetProductInformation(productID);
}
</script>
总结
ASP.NET
MVC是一个适用于大型Web应用开发的日益成熟的Web框架。MVC的架构思想是注重分离，对于具有Trial、Error、Discovery的Web应用开发而言，MVC的学习曲线就显得与众不同。MVC与我们过去一直使用的ASP.NET
Web Forms技术与Web Form post-back
model技术完全不同。在未来，MVC开发者需要更加注重新兴框架与开源库，增强型MVC的开发。
本文重点关注的是开源JavaScript库Knockout与JQuery，以及用于交换视图与控制器数据的JSON。建议MVC开发者也多多关注其它的开发工具与框架，特别是Backbone与JavaScriptMVC。作为比较，后续的文章将会在示例程序Northwind中引入Backbone与JavaScriptMVC。
