使用重力感应器accelerometer，需要引用类库Microsoft.Devices.Sensors ，所以需要在WMAppManifest.xml
加上
<Capability Name="ID_CAP_SENSORS" />

1. 代码  
2.  
3.  
4. using System;  
5. using System.Security;  
6.  
7. namespace Microsoft.Devices.Sensors  
8. {  
9.     // Summary:  
10.     //     Provides Windows?Phone applications access to the device’s accelerometer  
11.     //     sensor.  
12.     public sealed class Accelerometer : IDisposable  
13.     {  
14.         // Summary:  
15.         //     Creates a new instance of the Microsoft.Devices.Sensors.Accelerometer object.  
16.         [SecuritySafeCritical]  
17.         public Accelerometer();  
18.  
19.         // Summary:  
20.         //     Gets the current state of the accelerometer. The value is a member of the  
21.         //     Microsoft.Devices.Sensors.SensorState enumeration.  
22.         //  
23.         // Returns:  
24.         //     Type Microsoft.Devices.Sensors.SensorState.  
25.         public SensorState State { get; }  
26.  
27.         // Summary:  
28.         //     Occurs when new data arrives from the accelerometer.  
29.         public event EventHandler<AccelerometerReadingEventArgs> ReadingChanged;  
30.  
31.         // Summary:  
32.         //     Releases the managed and unmanaged resources used by the Microsoft.Devices.Sensors.Accelerometer.  
33.         [SecuritySafeCritical]  
34.         public void Dispose();  
35.         //  
36.         // Summary:  
37.         //     Starts data acquisition from the accelerometer.  
38.         [SecuritySafeCritical]  
39.         public void Start();  
40.         //  
41.         // Summary:  
42.         //     Stops data acquisition from the accelerometer.  
43.         [SecuritySafeCritical]  
44.         public void Stop();  
45.     }  
46. } 

X轴表示左右方向的重力大小

Y轴表示上下方向的重力大小

Z轴表示屏幕正上方下面的的重力大小

实例

1. 代码  
2.  
3.  
4. MainPage.xaml  
5. <phone:PhoneApplicationPage   
6.     x:Class="SilverlightAccelerometer.MainPage" 
7.     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
8.     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
9.     xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone" 
10.     xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone" 
11.     xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
12.     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
13.     FontFamily="{StaticResource PhoneFontFamilyNormal}" 
14.     FontSize="{StaticResource PhoneFontSizeNormal}" 
15.     Foreground="{StaticResource PhoneForegroundBrush}" 
16.     SupportedOrientations="PortraitOrLandscape" Orientation="Portrait" 
17.     mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768" 
18.     shell:SystemTray.IsVisible="True"> 
19.  
20.     <!--LayoutRoot contains the root grid where all other page content is placed--> 
21.     <Grid x:Name="LayoutRoot" Background="Transparent"> 
22.         <Grid.RowDefinitions> 
23.             <RowDefinition Height="Auto"/> 
24.             <RowDefinition Height="*"/> 
25.         </Grid.RowDefinitions> 
26.  
27.         <!--TitlePanel contains the name of the application and page title--> 
28.         <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28"> 
29.             <TextBlock x:Name="ApplicationTitle" Text="SILVERLIGHT ACCELEROMETER" Style="{StaticResource PhoneTextNormalStyle}"/> 
30.             <TextBlock x:Name="PageTitle" Text="main page" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/> 
31.         </StackPanel> 
32.  
33.         <!--ContentPanel - place additional content here--> 
34.         <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0"> 
35.             <TextBlock Name="txtblk" 
36.                         HorizontalAlignment="Center" 
37.                         VerticalAlignment="Center" /> 
38.         </Grid> 
39.     </Grid> 
40. </phone:PhoneApplicationPage> 

1. 代码  
2.  
3.  
4. MainPage.xaml.cs  
5. using System;  
6. using System.Windows;  
7. using System.Windows.Controls;  
8. using Microsoft.Devices.Sensors;  
9. using Microsoft.Phone.Controls;  
10.  
11. namespace SilverlightAccelerometer  
12. {  
13.     public partial class MainPage : PhoneApplicationPage  
14.     {  
15.         public MainPage()  
16.         {  
17.             InitializeComponent();  
18.  
19.             Accelerometer acc = new Accelerometer();//初始化一个重力感应器的类  
20.             acc.ReadingChanged += OnAccelerometerReadingChanged;//触发重力感应的事件  
21.  
22.             try  
23.             {  
24.                 acc.Start();//开始加速计重力感应  
25.             }  
26.             catch (Exception exc)  
27.             {  
28.                 txtblk.Text = exc.Message;  
29.             }  
30.         }  
31.  
32.         void OnAccelerometerReadingChanged(object sender, AccelerometerReadingEventArgs args)  
33.         {  
34.             string str = String.Format("X = {0:F2}\n" +     //x轴表示屏幕的左右    
35.                                        "Y = {1:F2}\n" +      //y轴表示屏幕的上下   
36.                                        "Z = {2:F2}\n\n" +    //z轴表示屏幕正上方的上下   
37.                                        "Magnitude = {3:F2}\n\n" +  
38.                                        "{4}",   
39.                                        args.X, args.Y, args.Z,   
40.                                        Math.Sqrt(args.X * args.X + args.Y * args.Y +   //计算加速度  
41.                                                                    args.Z * args.Z),                                         
42.                                        args.Timestamp);  
43.  
44.             if (txtblk.CheckAccess())//判断线程是否允许访问  
45.             {  
46.                 SetTextBlockText(txtblk, str);  
47.             }  
48.             else  
49.             {  
50.                 //重新激活线程  
51.                 txtblk.Dispatcher.BeginInvoke(new SetTextBlockTextDelegate(SetTextBlockText),   
52.                                               txtblk, str);  
53.             }  
54.         }  
55.  
56.         delegate void SetTextBlockTextDelegate(TextBlock txtblk, string text);  
57.  
58.         void SetTextBlockText(TextBlock txtblk, string text)  
59.         {  
60.             txtblk.Text = text;  
61.         }  
62.     }  
63. } 

本文转自linzheng 51CTO博客，原文链接:http://blog.51cto.com/linzheng/1079232