在Silverlight3中提供了NetworkChange，NetworkInterface这两个类（均为abstract型），其中实现了NetworkAddressChanged的事件处理器用来检测当前在线状态，而NetworkInterface类的 GetIsNetworkAvailable()方法(返回bool类型)，用来判断当前是否在线。有了这两个类，就可以很方便的实现动态检测当前应用是否连线了。
下面就是我写的一个DEMO，用于演示如何使用这两个方法，其中的XAML代码如下：
<UserControl x:Class="Off_Online.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Width="400" Height="300">
<Grid x:Name="LayoutRoot" Background="White">
<Grid.RowDefinitions>
<RowDefinition Height="150" />
<RowDefinition Height="150" />
</Grid.RowDefinitions>
<Image Width="100" Height="100" x:Name="StateIcon" Grid.Row="0" HorizontalAlignment="Center" />
<TextBlock Name="NetWorkState" Foreground="Red" FontSize="20" Grid.Row="1" FontWeight="Bold" HorizontalAlignment="Center" >当前状态未知</TextBlock>
</Grid>
</UserControl>
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Width="400" Height="300">
<Grid x:Name="LayoutRoot" Background="White">
<Grid.RowDefinitions>
<RowDefinition Height="150" />
<RowDefinition Height="150" />
</Grid.RowDefinitions>
<Image Width="100" Height="100" x:Name="StateIcon" Grid.Row="0" HorizontalAlignment="Center" />
<TextBlock Name="NetWorkState" Foreground="Red" FontSize="20" Grid.Row="1" FontWeight="Bold" HorizontalAlignment="Center" >当前状态未知</TextBlock>
</Grid>
</UserControl>
而相应的CS代码如下：
using System.Net.NetworkInformation;
namespace Off_Online
{
public partial class MainPage : UserControl
{
public MainPage()
{
InitializeComponent();
this.Loaded += new RoutedEventHandler(MainPage_Loaded);
}
void MainPage_Loaded(object sender, RoutedEventArgs e)
{
NetworkChange.NetworkAddressChanged += OnNetworkAddressChanged;
UpdateNetWorkState();
}
void UpdateNetWorkState()
{
string state = NetworkInterface.GetIsNetworkAvailable() ? "Online" : "Offline";
StateIcon.Source = new System.Windows.Media.Imaging.BitmapImage(new Uri("/Images/" + state + ".jpg", UriKind.Relative));
NetWorkState.Text = NetworkInterface.GetIsNetworkAvailable() ? "在线" : "离线";
}
void OnNetworkAddressChanged(object sender, EventArgs e)
{
UpdateNetWorkState();
}
}
}
namespace Off_Online
{
public partial class MainPage : UserControl
{
public MainPage()
{
InitializeComponent();
this.Loaded += new RoutedEventHandler(MainPage_Loaded);
}
void MainPage_Loaded(object sender, RoutedEventArgs e)
{
NetworkChange.NetworkAddressChanged += OnNetworkAddressChanged;
UpdateNetWorkState();
}
void UpdateNetWorkState()
{
string state = NetworkInterface.GetIsNetworkAvailable() ? "Online" : "Offline";
StateIcon.Source = new System.Windows.Media.Imaging.BitmapImage(new Uri("/Images/" + state + ".jpg", UriKind.Relative));
NetWorkState.Text = NetworkInterface.GetIsNetworkAvailable() ? "在线" : "离线";
}
void OnNetworkAddressChanged(object sender, EventArgs e)
{
UpdateNetWorkState();
}
}
}
下面就是其运行效果，首先是在线状态：
然后拔掉网线，就会显示离线状态了:
本文转自 daizhenjun 51CTO博客，原文链接：http://blog.51cto.com/daizhj/155510，如需转载请自行联系原作者