SilverLight:一步一步学Silverlight 2系列（1）：数据与通信之WebClient

 编写界面布局，XAML如下：   

<Grid Background="#46461F" x:Name="LayoutRoot" Loaded="LayoutRoot_Loaded">
        <Grid.RowDefinitions>
            <RowDefinition Height="40"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
            <RowDefinition Height="40"></RowDefinition>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition></ColumnDefinition>
        </Grid.ColumnDefinitions>
        <Border Grid.Row="0" Grid.Column="0" CornerRadius="15"
            Width="240" Height="36"
            Margin="20 0 0 0" HorizontalAlignment="Left">
            <TextBlock Text="书籍列表" Foreground="White"
                   HorizontalAlignment="Left" VerticalAlignment="Center"
                   Margin="20 0 0 0"></TextBlock>
        </Border>
        <ListBox x:Name="Books" Grid.Row="1" Margin="40 10 10 10"
             SelectionChanged="Books_SelectionChanged">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel>
                        <TextBlock Text="{Binding Name}" Height="32"></TextBlock>
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
        <Border Grid.Row="2" Grid.Column="0" CornerRadius="15"
            Width="240" Height="36" Background="Orange"
            Margin="20 0 0 0" HorizontalAlignment="Left">
            <TextBlock x:Name="lblPrice" Text="价格：" Foreground="White"
                   HorizontalAlignment="Left" VerticalAlignment="Center"
                   Margin="20 0 0 0"></TextBlock>
        </Border>
    </Grid>

 

在web项目中添加一个。ashx文件

 

public class BookHandler : IHttpHandler
    ...{
        public static readonly string[] PriceList = new string[] ...{ 
        "66.00",
        "78.30",
        "56.50",
        "28.80",
        "77.00"
        };
        public void ProcessRequest(HttpContext context)
        ...{
            context.Response.ContentType = "text/plain";
            context.Response.Write(PriceList[Int32.Parse(context.Request.QueryString["No"])]);

        }

        public bool IsReusable
        ...{
            get
            ...{
                return false;
            }
        }
    }

 

在page.xmal.cs写道

 

public partial class Page : UserControl
    ...{
        public Page()
        ...{
            InitializeComponent();
     
        }

        private void LayoutRoot_Loaded(object sender, RoutedEventArgs e)
        ...{
            List<Book> books = new List<Book>() ...{ 
        new Book("Professional ASP.NET 3.5"),
        new Book("ASP.NET AJAX In Action"),
        new Book("Silverlight In Action"),
        new Book("ASP.NET 3.5 Unleashed"),
        new Book("Introducing Microsoft ASP.NET AJAX")
    };

            Books.ItemsSource = books;
    

        }

        private void Books_SelectionChanged(object sender, SelectionChangedEventArgs e)
        ...{

            Uri endpoint = new Uri(String.Format("http://localhost:49955/BookHandler.ashx?No={0}", Books.SelectedIndex));

            WebClient client = new WebClient();
            client.DownloadStringCompleted += new DownloadStringCompletedEventHandler(client_DownloadStringCompleted);

            client.DownloadStringAsync(endpoint);
        }

        void client_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        ...{
            if (e.Error == null)
            ...{
                lblPrice.Text = "价格：" + e.Result;
            }
            else
            ...{
                lblPrice.Text = e.Error.Message;
            }
        }
    
  
    }

最终实现为