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  • 一步一步学Silverlight 2系列(18):综合实例之RSS阅读器

    版权声明:原创作品,允许转载,转载时请务必以超链接形式标明文章 原始出处 、作者信息和本声明。否则将追究法律责任。http://terrylee.blog.51cto.com/342737/67256

    概述

    Silverlight 2 Beta 1版本发布了,无论从Runtime还是Tools都给我们带来了很多的惊喜,如支持框架语言Visual Basic, Visual C#, IronRuby, Ironpython,对JSON、Web Service、WCF以及Sockets的支持等一系列新的特性。《一步一步学Silverlight 2系列》文章将从Silverlight 2基础知识、数据与通信、自定义控件、动画、图形图像等几个方面带您快速进入Silverlight 2开发
    本文将综合前面十七篇讲过的界面布局、样式、控件模板、数据绑定、网络通信等几个方面,来开发一个综合实例——简易RSS阅读器。

    界面布局

    我们最终完成的RSS阅读器界面如下:
    定义一个三行两列的Grid,分别放置顶部信息、分割线和下面的内容区:
    <Grid.RowDefinitions>
                <RowDefinition Height="50"></RowDefinition>
                <RowDefinition Height="20"></RowDefinition>
                <RowDefinition Height="*"></RowDefinition>
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                <ColumnDefinition Width="240"></ColumnDefinition>
                <ColumnDefinition Width="*"></ColumnDefinition>
                </Grid.ColumnDefinitions>
    设计顶部输入区域,对Grid第一行做合并,并且放置一个StackPanel:
    <StackPanel x:Name="Header" Orientation="Horizontal"
                Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2">
                <Image Source="Rss.png" Width="32" Height="32" Margin="10 0 10 0"></Image>
                <Border Style="{StaticResource titleBorder}">
                <TextBlock Text="基于Silverlight的RSS阅读器" Foreground="#FFFFFF"
                VerticalAlignment="Center" Margin="12 0 0 0"></TextBlock>
                </Border>
                <WatermarkedTextBox x:Name="feedAddress" Width="300" Height="35"
                FontSize="16" Margin="10 0 10 0">
                <WatermarkedTextBox.Watermark>
                <TextBlock Text="请输入有效的RSS地址" VerticalAlignment="Center"
                Foreground="#FBA430" FontSize="16"></TextBlock>
                </WatermarkedTextBox.Watermark>
                </WatermarkedTextBox>
                <Button x:Name="displayButton" Style="{StaticResource button}"
                Content="显 示" Click="displayButton_Click"></Button>
                <Button x:Name="fullScreenButton" Style="{StaticResource button}"
                Content="全 屏" Click="fullScreenButton_Click"></Button>
                </StackPanel>
    鉴于两个按钮的风格一致,在App.xaml中定义一个button样式:
    <Style x:Key="button" TargetType="Button">
                <Setter Property="Width" Value="100"></Setter>
                <Setter Property="Height" Value="35"></Setter>
                <Setter Property="Background" Value="#FBA430"></Setter>
                <Setter Property="Foreground" Value="#FBA430"></Setter>
                <Setter Property="FontSize" Value="16"></Setter>
                </Style>
                <Style x:Key="titleBorder" TargetType="Border">
                <Setter Property="CornerRadius" Value="10"></Setter>
                <Setter Property="Width" Value="220"></Setter>
                <Setter Property="Height" Value="40"></Setter>
                <Setter Property="Background">
                <Setter.Value>
                <LinearGradientBrush StartPoint="0,0">
                <GradientStop Color="#FBA430" Offset="0.0" />
                <GradientStop Color="#FEF4E7" Offset="0.5" />
                <GradientStop Color="#FBA430" Offset="1.0" />
                </LinearGradientBrush>
                </Setter.Value>
                </Setter>
                </Style>
    定义分割线,用Rectangle来表示:
    <StackPanel Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2" VerticalAlignment="Center">
                <Rectangle Style="{StaticResource rectangle}"/>
                </StackPanel>
    为了显示出渐变的样式,我们定义样式如下:
    <Style x:Key="rectangle" TargetType="Rectangle">
                <Setter Property="Width" Value="780"></Setter>
                <Setter Property="Height" Value="5"></Setter>
                <Setter Property="RadiusX" Value="3"></Setter>
                <Setter Property="RadiusY" Value="3"></Setter>
                <Setter Property="Fill">
                <Setter.Value>
                <LinearGradientBrush StartPoint="0,0">
                <GradientStop Color="#FEF4E7" Offset="0.0" />
                <GradientStop Color="#FBA430" Offset="1.0" />
                </LinearGradientBrush>
                </Setter.Value>
                </Setter>
                </Style>
    定义左边的列表区,用ListBox来显示,并且定义ItemTemplate:
    <ListBox x:Name="PostsList" Grid.Column="0" Grid.Row="2"
                Margin="10 5 5 10" SelectionChanged="PostsList_SelectionChanged">
                <ListBox.ItemTemplate>
                <DataTemplate>
                <TextBlock Text="{Binding Title.Text}"
                TextWrapping="Wrap" Width="200"/>
                </DataTemplate>
                </ListBox.ItemTemplate>
                </ListBox>
    最后定义右边的详细信息区域,在StackPanel中垂直放置三个Border:
    <StackPanel x:Name="Detail" Grid.Column="1" Grid.Row="2">
                <Border CornerRadius="10" Background="#CDFCAE" Margin="10 5 10 10"
                Width="540" Height="40">
                <TextBlock Text="{Binding Title.Text}"  TextWrapping="Wrap"
                VerticalAlignment="Center" Foreground="Red"/>
                </Border>
                <Border CornerRadius="10" Background="#CDFCAE" Margin="10 5 10 10"
                Width="540" Height="300">
                <TextBlock Text="{Binding Summary.Text}"  TextWrapping="Wrap"/>
                </Border>
                <Border CornerRadius="10" Background="#CDFCAE" Margin="10 5 10 10"
                Width="540" Height="40">
                <StackPanel Orientation="Horizontal">
                <TextBlock Text="评论日期:"  TextWrapping="Wrap"
                Foreground="Red" VerticalAlignment="Center"/>
                <TextBlock Text="{Binding PublishDate}"  TextWrapping="Wrap"
                Foreground="Red" VerticalAlignment="Center"/>
                </StackPanel>
                </Border>
                </StackPanel>
    界面布局到此大功告成。

    实现功能

    下面实现数据的获取,采用WebRequest来实现,也可以使用其他方式。
    /// <summary>
                /// 显示列表
                /// </summary>
                /// <param name="sender"></param>
                /// <param name="e"></param>
                private void displayButton_Click(object sender, RoutedEventArgs e)
                {
                Uri uri = new Uri(feedAddress.Text);
                WebRequest request = (WebRequest)WebRequest.Create(uri);
                request.BeginGetResponse(new AsyncCallback(responseReady), request);
                }
                void responseReady(IAsyncResult asyncResult)
                {
                WebRequest request = (WebRequest)asyncResult.AsyncState;
                WebResponse response = (WebResponse)request.EndGetResponse(asyncResult);
                XmlReader reader = XmlReader.Create(response.GetResponseStream());
                SyndicationFeed feed = SyndicationFeed.Load(reader);
                PostsList.ItemsSource = feed.Items;
                }
    显示详细信息:
    /// <summary>
                /// 查看详细信息
                /// </summary>
                /// <param name="sender"></param>
                /// <param name="e"></param>
                private void PostsList_SelectionChanged(object sender, SelectionChangedEventArgs e)
                {
                SyndicationItem item = PostsList.SelectedItem as SyndicationItem;
                Detail.DataContext = item;
                }
    实现全屏按钮的代码:
    /// <summary>
                /// 全屏显示
                /// </summary>
                /// <param name="sender"></param>
                /// <param name="e"></param>
                private void fullScreenButton_Click(object sender, RoutedEventArgs e)
                {
                Content contentObject = Application.Current.Host.Content;
                contentObject.IsFullScreen = !contentObject.IsFullScreen;
                }

    运行效果

    运行后界面如下:
     
    输入豆瓣的最新影评Feed:
     
    选择其中一项后,将显示出详细信息:
     

    结束语

    本文对前面十七篇内容做了一个小结,并开发出了一个简易RSS阅读器,你可以从这里下载本文示例代码。

    本文出自 “TerryLee技术专栏” 博客,请务必保留此出处http://terrylee.blog.51cto.com/342737/67256

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  • 原文地址:https://www.cnblogs.com/hdjjun/p/1361474.html
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