Silverlight没有提供GroupBox控件，自己动手写了一个。
Generic.xaml文件：

1. <ResourceDictionary 
2.     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
3.     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
4.     xmlns:local="clr-namespace:Sample"  
5.     xmlns:sys="clr-namespace:System;assembly=mscorlib"> 
6.  
7.     <Style TargetType="local:GroupBox"> 
8.         <Setter Property="Background" Value="White"></Setter> 
9.         <Setter Property="BorderBrush" Value="#687B8B"></Setter> 
10.         <Setter Property="BorderThickness" Value="1"></Setter> 
11.         <Setter Property="Padding" Value="6,10,6,6"></Setter> 
12.         <Setter Property="Template"> 
13.             <Setter.Value> 
14.                 <ControlTemplate TargetType="local:GroupBox"> 
15.                     <Grid> 
16.                         <Border Margin="0,8,0,0" CornerRadius="5" 
17.                                 Background="{TemplateBinding Background}" 
18.                                 BorderBrush="{TemplateBinding BorderBrush}" 
19.                                 BorderThickness="{TemplateBinding BorderThickness}"> 
20.                             <ContentPresenter Margin="{TemplateBinding Padding}" ></ContentPresenter> 
21.                         </Border> 
22.                         <Border Margin="10,0,10,0" Grid.Column="0" HorizontalAlignment="Left" VerticalAlignment="Top" 
23.                                 Background="{TemplateBinding Background}" > 
24.                             <TextBlock Margin="5,0" Text="{TemplateBinding Title}" ></TextBlock> 
25.                         </Border> 
26.                     </Grid> 
27.                 </ControlTemplate> 
28.             </Setter.Value> 
29.         </Setter> 
30.     </Style> 
31. </ResourceDictionary> 

GroupBox.cs文件：

1. using System.Windows; 
2. using System.Windows.Controls; 
3.  
4. namespace Sample 
5. { 
6.     /// <summary> 
7.     /// 分组框。 
8.     /// </summary> 
9.     public class GroupBox : ContentControl 
10.     { 
11.         public GroupBox() 
12.         { 
13.             this.DefaultStyleKey = typeof(GroupBox); 
14.         } 
15.  
16.         public static readonly DependencyProperty TitleProperty = 
17.             DependencyProperty.Register("Title", typeof (string), typeof (GroupBox), null); 
18.  
19.         /// <summary> 
20.         /// 获取或设置标题。 
21.         /// </summary> 
22.         public string Title 
23.         { 
24.             get { return (string) GetValue(TitleProperty); } 
25.             set { SetValue(TitleProperty, value); } 
26.         } 
27.     } 
28. } 

使用示例代码：

1. <UserControl x:Class="AutoCompleteBoxSample.GroupBoxSample" 
2.     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
3.     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
4.     xmlns:local="clr-namespace:Sample" Width="400" Height="300"> 
5.     <Grid x:Name="LayoutRoot" Margin="30" Background="White"> 
6.         <local:GroupBox Title="GroupBox的标题" > 
7.             <Button Content="GroupBox的内容"></Button>                 
8.         </local:GroupBox> 
9.     </Grid> 
10. </UserControl> 

示例效果图：