团购网站分站列表API的读取和解析
下面我们就开始使用WebClient类来实现一个调用REST服务的实例。在该示例中主要是调用一个团购网站开发的REST API，以实现该团购网站在全国各地分部的列表。下面是该团购网站开放的API接口地址：http://www.meituan.com/api/v1/divisions
打开这个链接我们看到如下的XML文档：
我们现在要做的就是将这些分站的列表在WP7
应用中显示出来。实际界面如下所示：
下面是实现WP7上读取团购网站的完整代码，分为XAML和C#两部分：
XAML：
<phone:PhoneApplicationPage
x:Class="MeiTuan.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768"
FontFamily="{StaticResource PhoneFontFamilyNormal}"
FontSize="{StaticResource PhoneFontSizeNormal}"
Foreground="{StaticResource PhoneForegroundBrush}"
SupportedOrientations="Portrait" Orientation="Portrait"
shell:SystemTray.IsVisible="True">
<!--LayoutRoot is the root grid where all page content is placed-->
<Grid x:Name="LayoutRoot" Background="Transparent">
<Grid.Resources>
<Style x:Key="ComboBoxItemStyle" TargetType="ComboBoxItem" >
<Setter Property="Foreground" Value="Black"/>
<Setter Property="Background" Value="LightGray"/>
</Style>
<Style x:Key="ComboBoxStyle" TargetType="ComboBox" >
<Setter Property="Foreground" Value="Black"/>
<Setter Property="Background" Value="Gray"/>
</Style>
</Grid.Resources>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!--TitlePanel contains the name of the application and page title-->
<StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
<TextBlock x:Name="ApplicationTitle" Text="REST 示例"
Style="{StaticResource PhoneTextNormalStyle}"/>
<TextBlock x:Name="PageTitle" Text="团购分站"
Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"
Height="99" Width="453" />
</StackPanel>
<!--ContentPanel - place additional content here-->
<Grid x:Name="ContentPanel" Margin="12,139,12,0" Grid.RowSpan="2">
<Button Content="点击获取分站列表!" Height="80" HorizontalAlignment="Left"
Margin="6,90,0,0" Name="button1"
VerticalAlignment="Top" Width="275" Click="button1_Click" />
<TextBlock Height="23" HorizontalAlignment="Left" Margin="12,1,0,0"
Name="textBlock3"
Text="REST API地址:" VerticalAlignment="Top" />
<TextBlock Height="56" HorizontalAlignment="Left" Margin="6,28,0,0"
Name="uriTextBlock" TextWrapping="Wrap" Text="{Binding}"
VerticalAlignment="Top" Width="447" />
<TextBlock Height="23" HorizontalAlignment="Left" Margin="12,242,0,0"
Name="textBlock5"
Text="分站列表:" VerticalAlignment="Top" />
<ListBox Height="352" HorizontalAlignment="Left" Margin="6,271,0,0" Name="listBox1"
VerticalAlignment="Top" Width="444" ItemsSource="{Binding}" >
<ListBox.ItemTemplate>
<DataTemplate>
<Border BorderBrush="{StaticResource PhoneForegroundBrush}" Width="418" BorderThickness="2"
Margin="2">
<StackPanel>
<TextBlock Text="{Binding Path=CityName}" TextWrapping="Wrap" />
</StackPanel>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Grid>
</phone:PhoneApplicationPage>
C#：
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 Microsoft.Phone.Controls;
using System.Xml.Linq;
namespace MeiTuan
{
public partial class MainPage : PhoneApplicationPage
{
// REST API 地址
String requestString =
"http://www.meituan.com/api/v1/divisions";
public MainPage()
{
InitializeComponent();
// 创建 WebClient 实例，并和OpenReadCompleted事件进行关联.
wc = new WebClient();
wc.OpenReadCompleted += new OpenReadCompletedEventHandler(wc_OpenReadCompleted);
}
// 调用团购网站分站列表服务
WebClient wc;
private void CallToWebService()
{
// 调用 OpenReadAsyc 生成一个 get 请求, 并将请求的url显示在文本框.
wc.OpenReadAsync(new Uri(requestString));
uriTextBlock.DataContext = string.Format(requestString);
}
/// <summary>
/// 异步读取数据完成
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void wc_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
XElement resultXml;
//查看是否有错误发生
if (e.Error != null)
{
return;
}
else
{
try
{
resultXml = XElement.Load(e.Result);
//根据返回的XML文档生成分站信息对象.
var searchResults =
from result in resultXml.Descendants("division")
select new SearchResult
{
// 只显示分站名
CityName = result.Element("name").Value
};
// 将列表框的数据源设置为获取到的分站信息数据
listBox1.DataContext = searchResults;
}
catch (System.Xml.XmlException ex)
{
uriTextBlock.Text = ex.Message;
}
}
}
private void button1_Click(object sender, RoutedEventArgs e)
{
CallToWebService();
}
}
public class SearchResult
{
public string CityName { get; set; }
}
}
x:Class="MeiTuan.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768"
FontFamily="{StaticResource PhoneFontFamilyNormal}"
FontSize="{StaticResource PhoneFontSizeNormal}"
Foreground="{StaticResource PhoneForegroundBrush}"
SupportedOrientations="Portrait" Orientation="Portrait"
shell:SystemTray.IsVisible="True">
<!--LayoutRoot is the root grid where all page content is placed-->
<Grid x:Name="LayoutRoot" Background="Transparent">
<Grid.Resources>
<Style x:Key="ComboBoxItemStyle" TargetType="ComboBoxItem" >
<Setter Property="Foreground" Value="Black"/>
<Setter Property="Background" Value="LightGray"/>
</Style>
<Style x:Key="ComboBoxStyle" TargetType="ComboBox" >
<Setter Property="Foreground" Value="Black"/>
<Setter Property="Background" Value="Gray"/>
</Style>
</Grid.Resources>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!--TitlePanel contains the name of the application and page title-->
<StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
<TextBlock x:Name="ApplicationTitle" Text="REST 示例"
Style="{StaticResource PhoneTextNormalStyle}"/>
<TextBlock x:Name="PageTitle" Text="团购分站"
Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"
Height="99" Width="453" />
</StackPanel>
<!--ContentPanel - place additional content here-->
<Grid x:Name="ContentPanel" Margin="12,139,12,0" Grid.RowSpan="2">
<Button Content="点击获取分站列表!" Height="80" HorizontalAlignment="Left"
Margin="6,90,0,0" Name="button1"
VerticalAlignment="Top" Width="275" Click="button1_Click" />
<TextBlock Height="23" HorizontalAlignment="Left" Margin="12,1,0,0"
Name="textBlock3"
Text="REST API地址:" VerticalAlignment="Top" />
<TextBlock Height="56" HorizontalAlignment="Left" Margin="6,28,0,0"
Name="uriTextBlock" TextWrapping="Wrap" Text="{Binding}"
VerticalAlignment="Top" Width="447" />
<TextBlock Height="23" HorizontalAlignment="Left" Margin="12,242,0,0"
Name="textBlock5"
Text="分站列表:" VerticalAlignment="Top" />
<ListBox Height="352" HorizontalAlignment="Left" Margin="6,271,0,0" Name="listBox1"
VerticalAlignment="Top" Width="444" ItemsSource="{Binding}" >
<ListBox.ItemTemplate>
<DataTemplate>
<Border BorderBrush="{StaticResource PhoneForegroundBrush}" Width="418" BorderThickness="2"
Margin="2">
<StackPanel>
<TextBlock Text="{Binding Path=CityName}" TextWrapping="Wrap" />
</StackPanel>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Grid>
</phone:PhoneApplicationPage>
C#：
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 Microsoft.Phone.Controls;
using System.Xml.Linq;
namespace MeiTuan
{
public partial class MainPage : PhoneApplicationPage
{
// REST API 地址
String requestString =
"http://www.meituan.com/api/v1/divisions";
public MainPage()
{
InitializeComponent();
// 创建 WebClient 实例，并和OpenReadCompleted事件进行关联.
wc = new WebClient();
wc.OpenReadCompleted += new OpenReadCompletedEventHandler(wc_OpenReadCompleted);
}
// 调用团购网站分站列表服务
WebClient wc;
private void CallToWebService()
{
// 调用 OpenReadAsyc 生成一个 get 请求, 并将请求的url显示在文本框.
wc.OpenReadAsync(new Uri(requestString));
uriTextBlock.DataContext = string.Format(requestString);
}
/// <summary>
/// 异步读取数据完成
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void wc_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
XElement resultXml;
//查看是否有错误发生
if (e.Error != null)
{
return;
}
else
{
try
{
resultXml = XElement.Load(e.Result);
//根据返回的XML文档生成分站信息对象.
var searchResults =
from result in resultXml.Descendants("division")
select new SearchResult
{
// 只显示分站名
CityName = result.Element("name").Value
};
// 将列表框的数据源设置为获取到的分站信息数据
listBox1.DataContext = searchResults;
}
catch (System.Xml.XmlException ex)
{
uriTextBlock.Text = ex.Message;
}
}
}
private void button1_Click(object sender, RoutedEventArgs e)
{
CallToWebService();
}
}
public class SearchResult
{
public string CityName { get; set; }
}
}
我们知道REST API大多数以XML或者Json之类的格式返回数据的，因此如何对这些XML和JSON数据进行解析就显得至关重要。本节的例子是使用LINQ来解析XML数据。这种语法相对于以前的XML文档解析可谓是非常简单和便捷，但是笔者并没有对该LINQ进行详细探讨，关于XML和JSON数据的解析将在下一节重点讲解。敬请期待。
