在数据透视项中，ListBox绑定不显示值

Im创建集合以显示在ListBoxTransactions中，并绑定为描述。但结果是，我在ListBoxTransactions.ItemsSource中只有名称集合，但没有值。不能使用ListBox.ItemTemplate

XAML

<phone:PivotItem Header="Journal">
      <Grid>
         <ListBox Name="ListBoxTransactions">
            <StackPanel Orientation="Horizontal">
               <TextBlock Text="{Binding Description}" FontSize="35"/>                            
            </StackPanel>
         </ListBox>
      </Grid>
</phone:PivotItem>

C#

public class TransactHelper
    {
        public string Description { get; set; }        
    }

public void ShowTransactions()
        {
            ListBoxTransactions.Items.Clear();
            var transactFulls = _workerDb.GeTransactFull();
            var list = new List<TransactHelper>();
            foreach (var t in transactFulls)
            {                
                list.Add(new TransactHelper { Description = t.Description });
            }
            this.ListBoxTransactions.ItemsSource = list; // dont view collection. only name collection

<ListBox Name="ListBoxTransactions" ItemContainerStyle="{DynamicResource MyItemStyle}">
<ListBox.Resources>
    <Style x:Key="MyItemStyle" TargetType="{x:Type ListBoxItem}">
        <Setter Property="Template">
            <Setter.Value>
                 <ControlTemplate>
                     <StackPanel Orientation="Horizontal">
                            <TextBlock Text="{Binding Description}" FontSize="35"/>                            
                      </StackPanel>
                 </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ListBox.Resources>
</ListBox>

ListBoxTransactions.Items.Clear();
this.ListBoxTransactions.ItemsSource = list;

ListBoxTransactions.ItemsSource = null;
this.ListBoxTransactions.ItemsSource = list;