Question

集合中的绑定项目工作正常，但是当我尝试绑定变量时Count不起作用，有人可以帮我吗？

<Label Text="{Binding Count}" TextColor="#4F4F4F" FontSize="10" FontAttributes="Bold"/>

我做了一个测试，将Label移出ListView并且它工作得很好，但我需要它在Listview中工作。

视图模型：

 class ListViewModel : INotifyPropertyChanged
        {
            public ObservableCollection<Item> Items { get; }

            public ListViewModel()
            {
                Items = new ObservableCollection<Item>(new[]
                {
                    new Item { Text = "Test 1", Detail = "Detail 1", Foto = "computer2.png" },
                    new Item { Text = "Test 2", Detail = "Detail 2", Foto = "computer4.png" },

                });          


            private int count = 1;
            public int Count
            {
                get { return count; }
                set
                {
                    count = value;
                    OnPropertyChanged();
                }
            }

XAML：

 <ListView  
            ItemsSource="{Binding Items}" 

            <ListView.Header>
                <StackLayout>

                  <Label Text="{Binding Count}"     
                  TextColor="#4F4F4F" FontSize="10" 
                  FontAttributes="Bold"/>  

                </StackLayout>
            </ListView.Header>

        </ListView>

Answer 1

尝试以下内容。此外，我假设您发布的内容不是您的完整代码，因为我们无法看到您的OnPropertyChanged实现或您如何设置计数。

<ContentPage
//BlahBlah Headings
x:Name="PageName">
    <ListView ItemsSource="{Binding Items}">
        <ListView.Header>
            <StackLayout>
            <Label Text="{Binding Source={x:Reference PageName}, Path=BindingContext.Count}"     
              TextColor="#4F4F4F" FontSize="10" 
              FontAttributes="Bold"/>
        </StackLayout>
        </ListView.Header>
    </ListView>
</ContentPage>

Answer 2

我已经完成了这个小回购，它没有特殊的绑定工作

ViewModel + Model

namespace TestRelativeLayout.ViewModels
{
    [ImplementPropertyChanged]
    public class MyPage4ViewModel
    {
        public ObservableCollection<Item> Items { get; set; }
        public int Counter { get; set; } = 111;
        public string MyCounterFooter { get; set; } = "888";

        public MyPage4ViewModel() {
            Items = new ObservableCollection<Item>(new[]
        {
                        new Item { Text = "Test 1", Detail = "Detail 1", Foto = "computer2.png" },
                        new Item { Text = "Test 2", Detail = "Detail 2", Foto = "computer4.png" },

                    });
        }

        public class Item
        {
            public string Detail { get; set; }
            public string Foto { get; set; }
            public string Text { get; set; }
        }
    }
}

的Xaml

namespace TestRelativeLayout.ViewModels
{
    [ImplementPropertyChanged]
    public class MyPage4ViewModel
    {
        public ObservableCollection<Item> Items { get; set; }
        public int Counter { get; set; } = 111;
        public string MyCounterFooter { get; set; } = "888";

        public MyPage4ViewModel() {
            Items = new ObservableCollection<Item>(new[]
        {
                        new Item { Text = "Test 1", Detail = "Detail 1", Foto = "computer2.png" },
                        new Item { Text = "Test 2", Detail = "Detail 2", Foto = "computer4.png" },

                    });
        }

        public class Item
        {
            public string Detail { get; set; }
            public string Foto { get; set; }
            public string Text { get; set; }
        }
    }
}

绑定不起作用，我做错了什么？

2 个答案: