Question

我正在创建一个Windows Phone 8应用程序我在应用程序中为玩家做了一个LongListSelector

LongListSelector

 <phone:LongListSelector x:Name="playersLongList" LayoutMode="List" IsGroupingEnabled="False" HorizontalAlignment="Left" Height="653" Margin="15,190,0,0" VerticalAlignment="Top" Width="412" SelectionChanged="playersLongList_SelectionChanged">
            <phone:LongListSelector.ItemTemplate>
                <DataTemplate>
                    <StackPanel x:Name="s1">
                        <TextBlock x:Name="playerName" Text="{Binding FirstName}" FontFamily="/Assets/Fonts/Moire Light.ttf#Moire Light" FontSize="48" />
                    </StackPanel>
                </DataTemplate>
            </phone:LongListSelector.ItemTemplate>
        </phone:LongListSelector>

现在，我需要的是当玩家点击某个项目时，该应用会显示一个MessageBox，显示所选项目的玩家名称，这就是我在EventHandler中的表现方式

 private void playersLongList_SelectionChanged(object sender, SelectionChangedEventArgs e)
 {
     var tb = sender as TextBlock;
     string fname = tb.Text;
     MessageBox.Show("hello"+fname);
 }

调试在NullReferenceException

显示string fname = tb.Text;

我做错了什么？

Answer 1

试试这个。

private void playersLongList_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    if (e.AddedItems.Count > 0)
    {
        Player p = e.AddedItems[0] as Player;
        string fname = p.FirstName;
        MessageBox.Show("hello"+fname);
    }
}

访问LongListSelector项时出现NullReferenceException

1 个答案: