using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Data.Services.Client;
using System.Collections.ObjectModel;
using Silverlight20.NorthwindDataService;
namespace Silverlight20.Communication
{
public partial
class DataService : UserControl
{
// 配置服务地址，数据服务要与 Silverlight 宿主放在相同的域上 Uri uri =
new Uri(
"DataService/NorthwindDataService.svc", UriKind.Relative);
NorthwindEntities ctx;
ObservableCollection<Categories> categories;
ObservableCollection<Products> products;
public DataService()
{
InitializeComponent();
this.Loaded +=
new RoutedEventHandler(DataService_Loaded);
}
void DataService_Loaded(
object sender, RoutedEventArgs e)
{
// 实例化 DataServiceContext ctx =
new NorthwindEntities(uri);
// 初始化 Categories 集合，为了做 OneWay ，所以是 ObservableCollection<Categories> 类型 categories =
new ObservableCollection<Categories>();
// 初始化 Products 集合，为了做 OneWay ，所以是 ObservableCollection<Products> 类型 products =
new ObservableCollection<Products>();
BindCategory();
}
private void BindCategory()
{
DataServiceQuery<Categories> query = ctx.Categories;
// IAsyncResult BeginExecute(AsyncCallback callback, object state) - 以异步方式发出请求 // AsyncCallback callback - 经典的 AsyncCallback 委托，指定回调方法 // object state - 传递给回调方法的自定义对象，此处必须是 DataServiceQuery<T> 类型 query.BeginExecute(OnBindCategoryCompleted, query);
// RequestUri - 请求服务的地址，因为数据服务发布的是REST，所以也可以用自己构造 URI 的方式去调用数据服务，详细的 URI 语法请参看 MSDN lblMsg.Text =
"读取类别数据中。。。" + query.RequestUri.ToString();
}
void OnBindCategoryCompleted(IAsyncResult ar)
{
try {
var query = ar.AsyncState
as DataServiceQuery<Categories>;
// EndExecute(IAsyncResult ar) - 获取异步查询的结果 var result = query.EndExecute(ar);
foreach (var item
in result)
{
categories.Add(item);
}
this.Dispatcher.BeginInvoke(() =>
{
dataGrid1.DataContext = categories;
lblMsg.Text = "";
});
}
catch (DataServiceRequestException ex)
{
lblMsg.Text = ex.ToString();
}
}
private void btnAdd_Click(
object sender, RoutedEventArgs e)
{
Categories category =
new Categories();
category.CategoryName = txtCategoryName.Text;
category.Description = txtDescription.Text;
ctx.AddToCategories(category);
for (
int i = 0; i < 10; i++)
{
var product =
new Products() { ProductName =
"测试用" + i.ToString() };
product.Categories = category;
ctx.AddToProducts(product);
// 多对一关系，使用 SetLink 建立连接，BeginSaveChanges() 的时候会一起发送到数据服务 ctx.SetLink(product,
"Categories", category);
}
ctx.BeginSaveChanges(OnAddCompleted, category);
lblMsg.Text =
"新增数据中。。。";
}
void OnAddCompleted(IAsyncResult ar)
{
try {
var x = ctx.EndSaveChanges(ar);
categories.Add(ar.AsyncState
as Categories);
this.Dispatcher.BeginInvoke(() =>
{
lblMsg.Text = "";
});
}
catch (DataServiceRequestException ex)
{
lblMsg.Text = ex.ToString();
}
}
private void DataGrid_SelectionChanged(
object sender, SelectionChangedEventArgs e)
{
var category = e.AddedItems[0]
as Categories;
BindProduct(category.CategoryID);
}
private void BindProduct(
int categoryId)
{
// 可以使用 Lambda 表达式或查询语法，然后将其转换为 DataServiceQuery<T> 再使用 DataServiceQuery<Products> query =
(from p
in ctx.Products where p.Categories.CategoryID == categoryId select p)
as DataServiceQuery<Products>;
lblMsg.Text =
"读取产品数据中。。。";
query.BeginExecute(OnBindProductCompleted, query);
}
void OnBindProductCompleted(IAsyncResult ar)
{
try {
var query = ar.AsyncState
as DataServiceQuery<Products>;
var result = query.EndExecute(ar);
products.Clear();
foreach (var item
in result)
{
products.Add(item);
}
this.Dispatcher.BeginInvoke(() =>
{
dataGrid2.DataContext = products;
lblMsg.Text = "";
});
}
catch (DataServiceRequestException ex)
{
lblMsg.Text = ex.ToString();
}
}
private void btnDelete_Click(
object sender, RoutedEventArgs e)
{
if (dataGrid1.SelectedItem !=
null)
{
try {
Categories category = dataGrid1.SelectedItem
as Categories;
DeleteCategory(category);
lblMsg.Text =
"删除中。。。";
}
catch (DataServiceRequestException ex)
{
lblMsg.Text = ex.ToString();
}
}
}
private void DeleteCategory(Categories category)
{
try {
// BeginLoadProperty(object entity, string propertyName, AsyncCallback callback, object state) - 开始加载指定属性的值的异步操作 // object entity - 需要加载属性的所属实体 // string propertyName - 需要加载属性的名称 // AsyncCallback callback - 经典的 AsyncCallback 委托，指定回调方法 // object state - 传递给回调方法的自定义对象 ctx.BeginLoadProperty(category,
"Products", OnLoadPropertyCompleted, category);
}
catch (DataServiceRequestException ex)
{
lblMsg.Text = ex.ToString();
}
}
void OnLoadPropertyCompleted(IAsyncResult ar)
{
Categories category = ar.AsyncState
as Categories;
try {
// EndLoadProperty(IAsyncResult ar) - 完成加载指定属性的值的这个异步操作 ctx.EndLoadProperty(ar);
foreach (Products product
in category.Products)
{
// 在指定的对象上删除指定的连接，BeginSaveChanges() 的时候会一起发送到数据服务 ctx.DeleteLink(category,
"Products", product);
}
ctx.DeleteObject(category);
ctx.BeginSaveChanges(OnDeleteCategoryCompleted,
null);
categories.Remove(category);
}
catch (DataServiceRequestException ex)
{
lblMsg.Text = ex.ToString();
}
}
void OnDeleteCategoryCompleted(IAsyncResult ar)
{
try {
ctx.EndSaveChanges(ar);
lblMsg.Text = "";
}
catch (DataServiceRequestException ex)
{
lblMsg.Text = ex.ToString();
}
}
private void btnUpdate_Click(
object sender, RoutedEventArgs e)
{
if (dataGrid1.SelectedItem !=
null)
{
try {
Categories category = dataGrid1.SelectedItem
as Categories;
ctx.UpdateObject(category);
ctx.BeginSaveChanges(OnUpdateCategoryCompleted, category);
lblMsg.Text =
"更新中。。。";
}
catch (DataServiceRequestException ex)
{
lblMsg.Text = ex.ToString();
}
}
}
void OnUpdateCategoryCompleted(IAsyncResult ar)
{
try {
ctx.EndSaveChanges(ar);
lblMsg.Text = "";
}
catch (DataServiceRequestException ex)
{
lblMsg.Text = ex.ToString();
}
}
}
}
