wpf - WPF 数据绑定(bind)是否会将更改编码到 UI 线程？

Question

我刚刚注意到在我的 ViewModel 中更改绑定(bind)属性时(MVVM)来自后台工作线程我没有得到任何异常并且 View 已正确更新。这是否意味着我可以安全地依赖 wpf 数据绑定(bind)编码 ViewModel 中的所有更改？到 UI 线程？我想我在某处读到应该确保(在 ViewModel 中)INotifyPropertyChanged.PropertyChanged在 UI 线程上触发。这在 3.5 中是否发生了变化？

Answer 1

是的标量，没有集合。对于集合，您需要一个专门的集合来为您编码，或者通过 Dispatcher 自己手动编码到 UI 线程。 .

你可能读过 INotifyCollectionChanged.CollectionChanged必须在 UI 线程上触发，因为 INotifyPropertyChanged.PropertyChanged 根本不正确.下面是一个非常简单的示例，它为您证明 WPF 编码属性更改。

Window1.xaml.cs:

using System.ComponentModel;
using System.Threading;
using System.Windows;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        private CustomerViewModel _customerViewModel;

        public Window1()
        {
            InitializeComponent();
            _customerViewModel = new CustomerViewModel();
            DataContext = _customerViewModel;

            var thread = new Thread((ThreadStart)delegate
            {
                while (true)
                {
                    Thread.Sleep(2000);
                    //look ma - no marshalling!
                    _customerViewModel.Name += "Appended";
                    _customerViewModel.Address.Line1 += "Appended";
                }
            });

            thread.Start();
        }
    }

    public abstract class ViewModel : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        protected void OnPropertyChanged(string propertyName)
        {
            var handler = PropertyChanged;

            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

    public class CustomerViewModel : ViewModel
    {
        private string _name;
        private AddressViewModel _address = new AddressViewModel();

        public string Name
        {
            get { return _name; }
            set
            {
                if (_name != value)
                {
                    _name = value;
                    OnPropertyChanged("Name");
                }
            }
        }

        public AddressViewModel Address
        {
            get { return _address; }
        }
    }

    public class AddressViewModel : ViewModel
    {
        private string _line1;

        public string Line1
        {
            get { return _line1; }
            set
            {
                if (_line1 != value)
                {
                    _line1 = value;
                    OnPropertyChanged("Line1");
                }
            }
        }
    }
}

Window1.xaml:

<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <StackPanel>
        <TextBox Text="{Binding Name}"/>
        <TextBox Text="{Binding Address.Line1}"/>
    </StackPanel>
</Window>