Question

我有这个Order类，我正在使用MVVM：

namespace drinksMVVM.Models
{
    public class Order : INotifyPropertyChanged
    {
    private Item _OrderItem;
    private ObservableCollection<Item> _Supplements;
    private double _OrderPrice;

    public Item OrderItem
    {
        get
        {
            return _OrderItem;
        }
        set
        {
            _OrderItem = value;
            OnPropertyChanged("OrderItem");
            _OrderPrice += _OrderItem.Price;
        }
    }

    public ObservableCollection<Item> Supplements
    {
        get
        {
            return _Supplements;
        }
        set
        {
            _Supplements = value;
            OnPropertyChanged("Supplements");
            foreach(var supplement in _Supplements)
            {
                _OrderPrice += supplement.Price;
            }
        }
    }

    public double OrderPrice
    {
        get
        {
            return _OrderPrice;
        }
        set
        {
            _OrderPrice = value;
            OnPropertyChanged("Price");
        }
    }

    public Order()
    {

    }

    public Order(Item item, ObservableCollection<Item> items)
    {
        _OrderItem = item;
        _Supplements = items;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(string property)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(property));
        }
    }
}
}

它包含Item类型的属性（属性Name和Price）和Item类型的ObservableCollection。 Order对象当然包含一个Item，它是一个单独的食物/饮料作为订单，但可以包含Item和ObservableCollection，这是一个带有额外补充剂的食物/饮料。

简单示例：我有咖啡加糖和奶油的订单，我想展示他们的东西：咖啡（OrderItem）糖+奶油（补品） 1,50（OrderPrice）在这种情况下，布局无关紧要

我的问题是如何在我的视图中显示数据。我有两个想法，不知道如何继续。

带有文本块的DataTemplate，每个文本块都绑定到Order类的属性，但不知道如何显示ObservableCollection中的每个项目名称。

<DataTemplate x:Key="OrderTemplate">
    <StackPanel Orientation="Vertical">
        <TextBlock x:Name="OrderName" Text="{Binding OrderItem.Name}"/>
        <TextBlock x:Name="OrderSupplements" 
         Text="{Binding Supplements[0].Name}"/> ///Can't solve this
         binding 
        <TextBlock x:Name="OrderPrce" Text="{Binding OrderPrice}"/>
    </StackPanel>
</DataTemplate>

2.Override Order类的ToString（）方法，以便在一个文本块中显示所有数据，但也无法找到如何显示所有补充名称的解决方案。

    public override string ToString()
    {
        return OrderItem.Name + " " +/*every single supplement name*/+" "
        +OrderPrice.ToString();
    }

和

    <DataTemplate x:Key="OrderTemplate1">
        <StackPanel Orientation="Vertical">
            <TextBlock x:Name="test" Text="{Binding}"/>
        </StackPanel>
    </DataTemplate>

Answer 1

就选项＃2而言......

public override string ToString()
{
    string orderStr = string.Empty;
    orderStr += _OrderItem.Name + " ";

    foreach(Item supplement in Supplements)
    {
        orderStr += supplement.Name + " ";
    }

    orderStr += OrderPrice.ToString();
    return orderStr;
}

Answer 2

我设法用IValueConverter

解决了选项＃1

[ValueConversion(typeof(List<Item>),typeof(string))]
public class MyConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        List<Item> items = (List<Item>)value;
        string supplementsString = string.Empty;
        if (items.Count >= 1)
        {
            foreach (var item in items)
            {
                supplementsString += item.Name + " " + item.Price.ToString() + " " + Environment.NewLine;
            }
        }
        return supplementsString;
    }

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

和XAML部分

<converters:MyConverter x:Key="MyConverterTest"/>

<TextBlock x:Name="OrderSupplements" 
     Text="{Binding Supplements, Converter={StaticResource MyConverter}}"/>

如何显示数据 - 绑定或覆盖ToString（）C＃WPF XAML

2 个答案: