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我创建了一个要在列表视图中使用的自定义控件。viewProgress除了根据我的订单状态返回布尔值的自定义属性外，它几乎可以正常工作。尽管状态正确地获取了他的值，但布尔值永远不会被重新读取，因此绑定永远不会收到真值。我尝试使用断点来检测是否OnPropertyChanged正在运行，但它似乎永远不会到达那里。Item即使数据已绑定，该属性似乎也永远不会设置。我究竟做错了什么？

内容视图：

<?xml version="1.0" encoding="UTF-8"?>
<ContentView xmlns="http://xamarin.com/schemas/2014/forms" 
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:HandTerminal"
             x:Class="HandTerminal.OrderItem">
  <ContentView.Content>
        <StackLayout>
            <Frame
                Margin="10,6,10,6"
                Padding="10"
                CornerRadius="10">
                <StackLayout>

                    <StackLayout
                        Padding="0"
                        HorizontalOptions="Fill"
                        Orientation="Horizontal">
                        <Label
                            FontAttributes="Bold"
                            FontSize="Medium"
                            Text="Ordernumber"
                            TextColor="{DynamicResource TitleTextColor}" />

                        <Label
                            FontSize="Medium"
                            HorizontalOptions="FillAndExpand"
                            HorizontalTextAlignment="End"
                            Text="{Binding Item.Ordernumber}"
                            TextColor="{DynamicResource SubtleTextColor}" />
                    </StackLayout>

                    <StackLayout
                        IsVisible="{Binding viewProgress}"
                        Orientation="Horizontal"
                        HorizontalOptions="FillAndExpand">
                        
                        <Label
                            HorizontalOptions="Start"
                            Text="Picked"
                            TextColor="{DynamicResource HighlightTextColor}" />

                        <ProgressBar 
                            HorizontalOptions="FillAndExpand"
                            Progress="{Binding Item.PickedProgress}" />

                        <StackLayout
                            HorizontalOptions="End"
                            Orientation="Horizontal"> 

                            <Label
                                Text="{Binding Item.TotalPicked}"
                                TextColor="{DynamicResource HighlightTextColor}" />
                            <Label
                                Text="/"
                                TextColor="{DynamicResource HighlightTextColor}" />
                            <Label
                                Text="{Binding Item.TotalAmount}"
                                TextColor="{DynamicResource HighlightTextColor}" />
                        </StackLayout>
                    </StackLayout>

                </StackLayout>
            </Frame>
        </StackLayout>
    </ContentView.Content>
</ContentView>

代码隐藏：

using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace HandTerminal
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class OrderItem : ContentView
    {
        public OrderItem()
        {
            InitializeComponent();
            Content.BindingContext = this;
        }

        public static BindableProperty ItemProperty = BindableProperty.Create(
            propertyName: "Item",
            returnType: typeof(Order),
            declaringType: typeof(OrderItem),
            defaultValue: new Order(),
            defaultBindingMode: BindingMode.OneWay);

        public Order Item
        {
            get
            {
                return (Order)GetValue(ItemProperty);
            }
            set
            {
                SetValue(ItemProperty, value);
                OnPropertyChanged("Item");
                OnPropertyChanged("viewProgress");
            }
        }
        
        public static BindableProperty viewProgressProperty = BindableProperty.Create(
            propertyName: "viewProgress",
            returnType: typeof(bool),
            declaringType: typeof(OrderItem),
            defaultValue: false,
            defaultBindingMode: BindingMode.OneWay);

        public bool viewProgress
        {
            get
            {
                if (Item.Status == OrderStatus.Picking)
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
        }
    }
}

使用自定义控件的 ContentPage：

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="HandTerminal.Orders"
             xmlns:controls="clr-namespace:HandTerminal"
    xmlns:d="clr-namespace:HandTerminal;assembly=HandTerminal">
    <ContentPage.Content>
        <StackLayout
            Orientation="Vertical"
            VerticalOptions="CenterAndExpand">

            <ListView
                HasUnevenRows="True"
                ItemsSource="{Binding Orders}"
                VerticalOptions="StartAndExpand">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                            <controls:OrderItem Item="{Binding .}" />
                        </ViewCell>
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
            
        </StackLayout>
    </ContentPage.Content>
</ContentPage>
4

1 回答 1

1

我试过你的代码，我的建议是：

  1. 创建一个 viewProgressConverter

     public class viewProgressConverter : IValueConverter{

 public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
 {
     OrderStatus myOrder =(OrderStatus) value ;
     if (myOrder == OrderStatus.Picking)
         return true;
     else return false;
 }

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

您必须将其添加到 App.Xaml 中的 AppResources

2.修改您的OrderItem View，删除所有“项目”。直接绑定到您的订单

<StackLayout
                    HorizontalOptions="FillAndExpand"
                    IsVisible="{Binding Status, Converter={StaticResource progressConverter}}"
                    Orientation="Horizontal">
  1. 您可以删除Content.BindingContext = this;和注释/删除所有可绑定的属性
于 2021-09-27T14:45:29.560 回答