Question

我有一个列表视图，其中的数据模板具有文本块，其文本值与数据绑定。

 <ListView ItemsSource="{Binding Items}"
              Grid.Row="2" 
              HorizontalAlignment="Left"
              Margin="10,70"


              Foreground="Red" >
        <ListView.ItemTemplate >

            <DataTemplate>

                 <TextBlock x:Name="TextBlock_PlayerOneBid"
                                   TextWrapping="Wrap"  
                                   Text="{Binding PlayerOneBid}" 
                                   FontSize="20"
                                   FontFamily="ArialBlack"
                                   Height="25"
                                   Width="23"
                                     TextAlignment="Center"
                                   />

                <TextBlock x:Name="TextBlock_PlayerTwoBid"
                                   TextWrapping="Wrap"                                  
                                   Text="{Binding PlayerTwoBid}" 
                                   FontSize="20"
                                   FontFamily="ArialBlack"
                                   Height="25"
                                   Width="23"
                                     TextAlignment="Center"
                                   />

              </DataTemplate>


        </ListView.ItemTemplate>



    </ListView>

我在这里遇到的问题是这个数据模板打印了两次。有4个文本块而不是2个。有没有办法从打印中重新定义模板，直到设置了所有值？

设置值的代码。

PlayerOneBid = 1 ;
PlayerTwoBid = 2 ;

Answer 1

创建一个可见性转换器，当字符串为空或空时返回Collapsed，否则返回Visible。

    public sealed class EmptyToVisibilityConverter : IValueConverter
{
  public object Convert(object value, Type targetType, object parameter, string language)
  {
    if (value == null) return Visibility.Collapsed;
    var str = value.ToString();
    return String.IsNullOrEmpty(str) ? Visibility.Collapsed : Visibility.Visible;
  }

  public object ConvertBack(object value, Type targetType, object parameter, string language)
  {
    throw new NotImplementedException();
  }
}

然后在您的页面上声明资源：

然后在每个TextBlock添加使用转换器：

 <ListView ItemsSource="{Binding Items}"
              Grid.Row="2" 
              HorizontalAlignment="Left"
              Margin="10,70"


              Foreground="Red" >
        <ListView.ItemTemplate >

            <DataTemplate>

                 <TextBlock x:Name="TextBlock_PlayerOneBid"
                                   TextWrapping="Wrap"  
                                   Text="{Binding PlayerOneBid}" 
                                   Visibility="{Binding PlayerOneBid, Converter={StaticResource EmptyToVisibilityConverter}}"
                                   FontSize="20"
                                   FontFamily="ArialBlack"
                                   Height="25"
                                   Width="23"
                                     TextAlignment="Center"
                                   />

                <TextBlock x:Name="TextBlock_PlayerTwoBid"
                                   TextWrapping="Wrap"                                  
                                   Text="{Binding PlayerTwoBid}" 
                                   Visibility="{Binding PlayerTwoBid, Converter={StaticResource EmptyToVisibilityConverter}}"
                                   FontSize="20"
                                   FontFamily="ArialBlack"
                                   Height="25"
                                   Width="23"
                                     TextAlignment="Center"
                                   />

              </DataTemplate>


        </ListView.ItemTemplate>



</ListView>

如何在更新所有绑定后重新打印xaml中的<datatemplate>（Windows Phone 8.1）

1 个答案: