标签：div 调用 线程 ui线程 oid this protected tor end
当ObservableCollection列表被UI线程占用时，如果在异步线程中调用ObservableCollection，会弹出以下异常：
我们使用一个viewModel，在ViewModel中添加ObservableCollection类型的ItemsSource列表。
在列表使用ListBox绑定ItemsSource列表。再由界面触发对ItemsSource的修改。
1 public class ViewModel : INotifyPropertyChanged 2 { 3 private ObservableCollection<string> _itemsSource = new ObservableCollection<string>(); 4 5 public ObservableCollection<string> ItemsSource 6 { 7 get => _itemsSource; 8 set 9 { 10 _itemsSource = value; 11 OnPropertyChanged(); 12 } 13 } 14 15 public event PropertyChangedEventHandler PropertyChanged; 16 17 [NotifyPropertyChangedInvocator] 18 protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null) 19 { 20 PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)); 21 } 22 }
1. 直接在异步线程下修改ObservableCollection--报错
1 private void ButtonBase_OnClick(object sender, RoutedEventArgs e) 2 { 3 var viewModel = this.DataContext as ViewModel; 4 Task.Run(() => 5 { 6 //此段调用异常 7 viewModel.ItemsSource.Add("test1"); 8 }); 9 }
2. 在异步线程下，赋值ObservableCollection--正常
1 private void ButtonBase_OnClick(object sender, RoutedEventArgs e) 2 { 3 var viewModel = this.DataContext as ViewModel; 4 Task.Run(() => 5 { 6 //此段不会报错 7 var list = viewModel.ItemsSource.ToList(); 8 list.Add("test0"); 9 viewModel.ItemsSource = new ObservableCollection<string>(list); 10 }); 11 }
3. 在异步线程下，赋值ObservableCollection后，再修改ObservableCollection--正常
1 private void Button1_OnClick(object sender, RoutedEventArgs e) 2 { 3 var viewModel = this.DataContext as ViewModel; 4 Task.Run(() => 5 { 6 //此段不会报错 7 viewModel.ItemsSource = new ObservableCollection<string>(new List<string>() { "test3", "test2" }); 8 //此段不会报错 9 viewModel.ItemsSource.Add("test4"); 10 }); 11 }
在异步线程下设置的ItemsSource，可以被当前异步线程调用。
4. 异步线程下赋值ObservableCollection，然后在UI线程修改ObservableCollection--正常
1 private void Button1_OnClick(object sender, RoutedEventArgs e) 2 { 3 var viewModel = this.DataContext as ViewModel; 4 Task.Run(() => 5 { 6 //此段不会报错 7 viewModel.ItemsSource = new ObservableCollection<string>(new List<string>() { "test0" }); 8 }); 9 } 10 11 12 private void Button2_OnClick(object sender, RoutedEventArgs e) 13 { 14 var viewModel = this.DataContext as ViewModel; 15 //此段不会报错 16 viewModel.ItemsSource.Add("test2"); 17 }
在异步线程下设置的ItemsSource，可以被UI线程调用。此处可以理解为，赋值时，框架默默转到UI线程处理了？
但是上面4流程，为何正常，so weird~
5. 异步线程下，回到UI线程中，修改ObservableCollection--正常
1 private void Button1_OnClick(object sender, RoutedEventArgs e) 2 { 3 var viewModel = this.DataContext as ViewModel; 4 Task.Run(() => 5 { 6 Application.Current.Dispatcher.Invoke(() => 7 { 8 //此段不会报错 9 viewModel.ItemsSource.Add("test"); 10 }); 11 }); 12 }
WPF ObservableCollection 异步调用问题
标签：div 调用 线程 ui线程 oid this protected tor end
原文地址：https://www.cnblogs.com/kybs0/p/10785489.html
