Question

我有ListBox我显示所有订单位置。我需要显示价格。我创建了一个ValueConverter，它接受一个OrderPosition对象并将我的价格返回为double。公式：金额* Product.Price（Amount和Product是OrderPosition）中的属性

我的XAML不会显示任何内容：

<ListBox Grid.Row="1" Grid.Column="0" Margin="3" ItemsSource="{Binding SelectedOrder.OrderPositions}">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*" />
                        <ColumnDefinition Width="*" />
                    </Grid.ColumnDefinitions>
                    <TextBlock Grid.Column="0">
                        <TextBlock.Text>
                            <MultiBinding StringFormat="{}{0}x {1}">
                                <Binding Path="Amount" />
                                <Binding Path="Product.Label" />
                            </MultiBinding>
                        </TextBlock.Text>
                    </TextBlock>
                    <TextBlock Text="{Binding /, Converter={StaticResource PositionPriceConverter}, StringFormat={}{0:c}}" Grid.Column="1"
                                   TextAlignment="Right" />
                </Grid>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

这是我的转换器：

public class PositionPriceConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        var position = (OrderPosition)value;
        return position.Amount * position.Product.Price;
    }

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

Answer 1

目前您设置了Path=/，并将其绑定到CollectionView.CurrentItem

当源是集合视图时，可以使用斜杠（/）指定当前项。例如，子句Path = /设置绑定到视图中的当前项。当源是集合时，此语法指定默认集合视图的当前项。

您可以通过设置Path=.或完全设置Path来实现您所追求的目标。

<TextBlock Text="{Binding Path=., Converter=...}

或

<TextBlock Text="{Binding Converter=...}

但请注意，当Amount或Product.Price发生变化时，它不会触发更新，因此MultiBinding和IMultiValueConverter可能是更好的选择。

Answer 2

             <ListBox Grid.Row="1"
                     Grid.Column="0"
                     Margin="3"
                     ItemsSource="{Binding SelectedOrder.OrderPositions}">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="*" />
                                <ColumnDefinition Width="*" />
                            </Grid.ColumnDefinitions>
                            <TextBlock Grid.Column="0">
                                <TextBlock.Text>
                                    <MultiBinding StringFormat="{}{0}x {1}">
                                        <Binding Path="Amount" />
                                        <Binding Path="Product.Label" />
                                    </MultiBinding>
                                </TextBlock.Text>
                            </TextBlock>
                            <TextBlock Grid.Column="1">
                                <TextBlock.Text>
                                    <MultiBinding Converter="{StaticResource PositionPriceConverter}" StringFormat="{}{0}x {1}">
                                        <Binding Path="Amount" />
                                        <Binding Path="Product.Label" />
                                    </MultiBinding>
                                </TextBlock.Text>
                            </TextBlock>
                        </Grid>
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>

像这样更改转换器，

public class PositionPriceConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        var amt = (double)values[0];
        var price = (double) values[1];
        return amt * price;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Answer 3

我不确定您提供给绑定的路径是否合法（{Binding /, Converter....）。

尝试更改它：

<TextBlock Text="{Binding Converter={StaticResource PositionPriceConverter}, StringFormat={}{0:c}}" Grid.Column="1" TextAlignment="Right" />

或

<TextBlock Text="{Binding Path=., Converter={StaticResource PositionPriceConverter}, StringFormat={}{0:c}}" Grid.Column="1" TextAlignment="Right" />

将当前项传递给ValueConverter

3 个答案: