这个实例是利用前文提到的汇率API（http://xurrency.com/）实现货币转换，因为该API免费用户每天10次的限制，本程序其实是没有什么实用性的，当然，你可以考虑购买他们的服务，好像每年29.99欧元（老外的钱比较好赚）。在Windows Phone 7上解析JSON跟普通的桌面程序有些不同，因为命名空间System.Runtime.Serialization.Json不在System.Runtime.Serialization里，而是在System.Servicemodel.Web里，所以在添加引用的时候必须同时引用System.Runtime.Serialization和System.Servicemodel.Web。 上个UI效果图: 
xaml布局代码:
<phone:PhoneApplicationPage
x:Class="PhoneApp1.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"
xmlns:toolkit="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls.Toolkit"
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.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="PageTitle" Text="货币换算器" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>
</StackPanel>
<!--ContentPanel - place additional content here-->
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<toolkit:ListPicker Header="现有货币" Name="listPicker1" Margin="9,22,268,475">
</toolkit:ListPicker>
<toolkit:ListPicker Header="兑换货币" Margin="257,19,20,486" Name="listPicker2">
</toolkit:ListPicker>
<TextBlock Height="36" HorizontalAlignment="Left" Margin="161,187,0,0" Name="textBlock1" Text="输入金额：" VerticalAlignment="Top" Width="143" />
<TextBox Height="76" HorizontalAlignment="Left" Margin="51,229,0,0" Name="textBox1" Text="" VerticalAlignment="Top" Width="351" />
<TextBlock Height="110" HorizontalAlignment="Left" Margin="28,348,0,0" Name="textBlock2" Text="" VerticalAlignment="Top" Width="408" />
<Button Content="兑换" HorizontalAlignment="Left" Margin="100,518,0,35" Name="button1" Width="231" Click="button1_Click" />
<ProgressBar Height="28" HorizontalAlignment="Left" Margin="7,368,0,0" Name="progressBar1" VerticalAlignment="Top" Width="441" Foreground="Green" Visibility="Collapsed" IsIndeterminate="True" />
</Grid>
</Grid>
</phone:PhoneApplicationPage>
两个ListPicker 两个TextBlock，一个TextBox,一个Button,一个ProgressBar,ListPicker的使用请参考Windows Phone 7下拉菜单的实现 Silverlight for Windows Phone Toolkit中ListPicker的使用 C#代码：
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.IO;
using System.Text;
using System.Runtime.Serialization.Json;
using System.Runtime.Serialization;
namespace PhoneApp1
{
public partial class MainPage : PhoneApplicationPage
{
// Constructor
string[] codeList;
string[] nameList;
public MainPage()
{
InitializeComponent();
nameList = new string[19]{ "人民币", "欧元", "美元", "英镑", "澳元", "港币", "日元", "新台币", "加拿大元", "韩元", "瑞士法郎", "丹麦克朗", "印度卢比", "新西兰元", "新加坡元", "泰铢", "南非兰特", "斯里兰卡卢比", "马来西亚林吉特" };
codeList = new string[19]{ "cny", "eur", "usd", "gbp","aud", "hdk", "jpy", "twd", "cad", "krw", "chf", "dkk", "inr", "nzd", "sgd", "thb", "zar", "lkr", "myr" };
//定义两数组，一个存中文货币名，一个存英文代码
for (int i = 0; i < nameList.Length; i++)
{
listPicker1.Items.Add(nameList[i] + "(" + codeList[i].ToUpper() + ")");
listPicker2.Items.Add(nameList[i] + "(" + codeList[i].ToUpper() + ")");
}
//填充两个ListPicker
//ListPicker并不是Windows Phone 7标准控件，使用方法请参考 http://www.pocketdigi.com/20110910/466.html
}
[DataContract(Namespace = "http://www.pocketdigi.com")]
public class Currency
//不public会抛System.Security.SecurityException异常
{
[DataMember(Order = 0)]
public result result { get; set; }
[DataMember(Order = 1)]
public int code { get; set; }
[DataMember(Order = 2)]
public string status { get; set; }
}
[DataContract(Namespace = "http://www.pocketdigi.com")]
public class result
{
[DataMember(Order = 0)]
public string updated_at { get; set; }
[DataMember(Order = 1)]
public float value { get; set; }
[DataMember(Order = 2)]
public string target { get; set; }
[DataMember(Order = 3)]
public string Base { get; set; }
}
//与前文 C# 解析与生成JSON http://www.pocketdigi.com/20110921/484.html 相同
//定义序列化方法,这里用不着
//private static string Serialize(Currency currency)
//{
// using (MemoryStream ms = new MemoryStream())
// {
// DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(Currency));
// serializer.WriteObject(ms, currency);
// ms.Position = 0;
// using (StreamReader reader = new StreamReader(ms))
// {
// return reader.ReadToEnd();
// }
// }
//}
//定义反序列化方法
private static Currency Deserialize(string jsonString)
{
using (MemoryStream ms = new MemoryStream(Encoding.Unicode.GetBytes(jsonString)))
{
DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(Currency));
return (Currency)serializer.ReadObject(ms);
}
}
private void button1_Click(object sender, RoutedEventArgs e)
{
progressBar1.Visibility = Visibility.Visible;
//显示进度条
WebClient webClient = new WebClient();
webClient.DownloadStringCompleted +=new DownloadStringCompletedEventHandler(webClient_DownloadStringCompleted);
//添加下载完成事件处理器,在异步数据下载完成时触发
string url = "http://xurrency.com/api/"+codeList[listPicker1.SelectedIndex]+"/"+codeList[listPicker2.SelectedIndex]+"/"+textBox1.Text;
webClient.DownloadStringAsync(new Uri(url));
}
private void webClient_DownloadStringCompleted(Object sender, DownloadStringCompletedEventArgs e)
{
string result = e.Result;
result=result.Replace("base", "Base");
//base是c#关键字，必须替换
var mStream = new MemoryStream(Encoding.UTF8.GetBytes(result));
DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(Currency));
Currency readCurrency = (Currency)serializer.ReadObject(mStream);
//反序列化，得到Currency类实例
textBlock2.Text = readCurrency.result.value.ToString();
textBlock2.Text += "\n汇率更新时间:\n";
textBlock2.Text += readCurrency.result.updated_at;
//更新UI
progressBar1.Visibility = Visibility.Collapsed;
//隐藏进度条
}
}
}
最后附上源码： [download id=”24”]