Windows phone 7 如何在LongListSelector中隐藏组标题？

如果列表中的项目数较少（如WP中的应用程序列表，如果应用程序少于30个），我想在

LongListSelector

中隐藏组标题

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

LongListSelector.ItemsSource=myList；
如果（myList.Count<10）
{
//隐藏组标题
}

这可能吗

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

更新

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

因此，我尝试：

LongListSelector.ItemsSource = myList; 
     if (myList.Count < 10) 
     {
        LongListSelector.GroupHeaderTemplate = null;
     }

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

LongListSelector.ItemsSource=myList；
如果（myList.Count<10）
{
LongListSelector.GroupHeaderTemplate=null；
}

它是有效的，但我仍然在等待更美好的建议。谢谢！：）

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

编辑

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

我的长列表选择器：

<phone:LongListSelector 
                          Name="UsersListGroup"
                          IsGroupingEnabled="True" 
                          LayoutMode="List"
                          HideEmptyGroups="False"      
                          ItemTemplate="{StaticResource usersItemTemplate}"
                          GroupHeaderTemplate="{StaticResource groupHeaderTemplate}"
                          JumpListStyle="{StaticResource LongListSelectorJumpListStyle}"                          
                          Margin="1,36,-1,10"
                          VirtualizingStackPanel.VirtualizationMode="Recycling"/>

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

模板：

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

政务司司长：

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

私有静态ObservableCollection GetItemGroups（IEnumerable itemList，Func getKeyFunc）
{
IEnumerable groupList=来自itemList中的项
按getKeyFunc（项）将项分组为g
orderby g.Key
选择新组（Convert.ToString（g.Key.ToLower（）[0]），g）；
var groupObservable=新的ObservableCollection（groupList）；
可观察的回报率；
}
私有ObservableCollection GetUserGroups（ObservableCollection collectionFriends）
{                                       
返回GetItemGroups（collectionFriends，c=>Convert.ToString（c.Name.ToLower（）[0]）；
}
Friends=GetUserGroups（新的ObservableCollection（response.Result.Friends））；
UsersListGroup.ItemsSource=朋友；

是否使用WP8内置的LongListSelector？如果是，请尝试将IsGroupingEnabled设置为false

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

---

如果您使用的是控件中的WP7版本，请尝试在页面资源中定义两个数据模板，其中一个具有宽度和高度为0的网格，如果项目数<10，请将GroupHeaderTemplate交换到该数据模板。

谢谢您的回答。我使用WP8并尝试使用启用分组，但如果我将属性设置为false，则列表为空：（我可能需要更仔细地看一下您的代码……您能把它放在这里吗？看看……从我的头顶上，您能试着从这个语句中删除orderby并通过getKeyFunc（item）选中？IEnumerable groupList=from item-in-itemList-group-item-in-item-in-itemList-group-item）进入g orderby g.Key选择新组（Convert.ToString（g.Key.ToLower（）[0]），g）；我检查了它，再次得到了空列表。嘿……对我来说，最简单的方法似乎是在页面中定义一个空数据模板，并将其设置为GroupHeaderTemplate

<DataTemplate x:Key="usersItemTemplate">
    <Grid x:Name="FriendsPanel" Grid.Row="1" Margin="12,0,12,0">            
        <StackPanel Name="FriendPanel" Orientation="Horizontal" Margin="0,0,0,17" Tag="{Binding Id}" Tap="FriendPanel_Tap" >
            <Image Height="75" 
                   Width="75" 
                   HorizontalAlignment="Left" 
                   Margin="6,0,9,0" 
                   Name="Avatar" 
                   Stretch="Fill" 
                   VerticalAlignment="Top" 
                   Source="{Binding Avatar, StringFormat=http://myurl.com/\{0\}}"/>
            <TextBlock Text="offline" 
                       TextWrapping="Wrap"
                       Margin="-75,78,0,0" 
                       Style="{StaticResource PhoneTextSmallStyle}" >
                 <i:Interaction.Triggers>     
                         <ec:DataTrigger Binding="{Binding IsOnline}" Value="1">
                              <ec:ChangePropertyAction PropertyName="Text" Value="online"/>
                         </ec:DataTrigger>
                 </i:Interaction.Triggers>
            </TextBlock>
            <StackPanel >
                <TextBlock
                           Text="{Binding Name}" 
                           TextWrapping="Wrap" 
                           Style="{StaticResource PhoneTextExtraLargeStyle}">
                </TextBlock>
                <TextBlock Text="{Binding Aboutself}" 
                           TextWrapping="Wrap" 
                           Margin="12,-6,12,0" 
                           Style="{StaticResource PhoneTextSubtleStyle}"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</DataTemplate>

<Style x:Key="LongListSelectorJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="Purple" 
                        Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Title}"
                               FontFamily="{StaticResource PhoneFontFamilySemiBold}"  
                               FontSize="48" Padding="6" 
                               Foreground="White"
                               VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>