SilverLight中 数据与通信之WebRequest
1. 新建一个处理类BookHandler.ashx
public class BookHandler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
//context.Response.ContentType = "text/plain";
//context.Response.Write(PriceList[Int32.Parse(context.Request.QueryString["No"])]);
context.Response.ContentType = "text/plain";
context.Response.Write(PriceList[Int32.Parse(context.Request.Form["No"])]);
}
public bool IsReusable
{
get
{
return false;
}
}
public static readonly string[] PriceList = new string[] {
"66.00",
"78.30",
"56.50",
"28.80",
"77.00"
};
}
2. 调用
<Grid x:Name="LayoutRoot" Background="#46461F">
<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>
public partial class MainPage : UserControl
{
private string bookNo = "0";
public MainPage()
{
InitializeComponent();
Loaded += new RoutedEventHandler(MainPage_Loaded);
}
void MainPage_Loaded(object sender,RoutedEventArgs e)
{
List<Book> books = new List<Book>() {
new Book("精通 ASP.NET 3.5"),
new Book("ASP.NET AJAX 实践"),
new Book("Silverlight 实践"),
new Book("ASP.NET 3.5 Unleashed"),
new Book("Introducing Microsoft ASP.NET AJAX")
};
Books.ItemsSource = books;
}
void Books_SelectionChanged(object sender,SelectionChangedEventArgs e)
{
bookNo = Books.Selectedindex.ToString();
//这里涉及两个问题：
//1.跨线程更新UI //可参考 http://www.cnblogs.com/RChen/archive/2008/07/25/1250948.html
//2.跨域调用
Uri endpoint = new Uri("http://localhost:4699/BookHandler.ashx");
WebRequest request = WebRequest.Create(endpoint);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.BeginGetRequestStream(new AsyncCallback(RequestReady),request);
}
void RequestReady(IAsyncResult asyncResult)
{
WebRequest request = asyncResult.AsyncState as WebRequest;
Stream requestStream = request.EndGetRequestStream(asyncResult);
using (StreamWriter writer = new StreamWriter(requestStream))
{
writer.Write(String.Format("No={0}",bookNo));
writer.Flush();
}
//
request.BeginGetResponse(new AsyncCallback(ResponseReady),request);
}
void ResponseReady(IAsyncResult asyncResult)
{
WebRequest request = asyncResult.AsyncState as WebRequest;
WebResponse response = request.EndGetResponse(asyncResult);
using (Stream responseStream = response.GetResponseStream())
{
StreamReader reader = new StreamReader(responseStream);
//更新界面
lblPrice.dispatcher.BeginInvoke(new UpdatePriceDelegate(UpdatePrice),reader.ReadToEnd());
}
}
private delegate void UpdatePriceDelegate(string price);
private void UpdatePrice(string price)
{
lblPrice.Text = "价格:" + price;
}
}
public class Book
{
public Book(string name)
{
this.Name = name;
}
public string Name
{
get;
set;
}
}
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