c# - ListView 未使用绑定(bind)列表更新

Question

我正在尝试实现一个简单的应用程序:我的 ViewModel 中有一个对象列表，我想在带有数据模板的 ListView 中显示。在我添加一个在列表中添加元素的按钮之前，一切都适用于绑定(bind)。当我这样做时， ListView 不会更新。但是，如果我尝试在列表中向下滚动，整个程序会停止并出现以下消息:

"The application is in break mode, Your app has entered a break state, but there is no code to show because all threads were executing external code (typically system or framework code)."

这是代码:
型号类:

namespace WpfTest
{
    class Model
    {
        public string Value1 { get; set; }
        public int Value2 { get; set; }
        public bool Value3 { get; set; }

        public Model()
        {
            Value1 = "abc";
            Value2 = 3;
            Value3 = true;
        }
    }
}

View 模型类:

namespace WpfTest
{
    class ViewModel : INotifyPropertyChanged
    {
        public List<Model> _model;
        private ICommand _addElement;

        public ViewModel()
        {
            _addElement = new RelayCommand(Add);
            _model = new List<Model>()
            {
                new Model(),
                new Model()
            };
        }

        public List<Model> ModelList
        {
            get => _model;
            set => _model = value;
        }

        public ICommand AddElement
        {
            get => _addElement;
            set => _addElement = value;
        }

        public void Add(object o)
        {
            _model.Add(new Model());
            OnPropertyChanged("ModelList");
        }

        public event PropertyChangedEventHandler PropertyChanged;

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

XAML View :

<Window x:Class="WpfTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfTest"
        xmlns:Mod="clr-namespace:WpfTest" 
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <DataTemplate DataType="{x:Type Mod:Model}">
            <StackPanel Orientation="Horizontal">
                <Label Content="{Binding Value1}"></Label>
                <Label Content="{Binding Value2}"></Label>
                <Label Content="{Binding Value3}"></Label>
            </StackPanel>
        </DataTemplate>
    </Window.Resources>
    <StackPanel>
        <Button Command="{Binding AddElement}">Add</Button>
        <ListView ItemsSource="{Binding ModelList}"></ListView>
    </StackPanel>
</Window>

我正在使用最新版本的 Visual Studio Community 2017

在此先感谢您的帮助

Answer 1

替换 List<Model>与 ObservableCollection<Model> .当列表的内容发生更改时，这将正确通知任何绑定(bind)的 UI 元素。

如果您希望在 UI 中反射(reflect)对单个模型对象的更新，则模型类必须实现 INotifyPropertyChanged ，并且相应地更新了属性定义。