WPF MVVM中DataGrid单元格无法从绑定源实时更新的问题

我开发基于.NET 8.0的WPF MVVM应用，使用Binding实现数据绑定，简化代码如下：

XAML代码 #

<TabControl x:Name="tbcGeneral"
            DataContext="{Binding Path=AppCoreInstance, RelativeSource={RelativeSource AncestorType=local:FirstWindow}}">
    <Button x:Name="btnAssignPilot"
            Command="{Binding Path=JobManagingInstance.AssignPilotCommand}">
        <Label x:Name="lblAssignPilot"
               Content="_Assign pilot"/>
    </Button>

    <DataGrid x:Name="dgrMannedSpaceships"
              ItemsSource="{Binding Path=HRManagementInstance.AvailableSpaceships}"
              AutoGenerateColumns="False"
              IsReadOnly="True"
              SelectedItem="{Binding Path=HRManagementInstance.CurrentSpaceship}"
              IsSynchronizedWithCurrentItem="True">
        <DataGrid.Columns>
            <DataGridTextColumn Header="Spaceship number"
                                Binding="{Binding NumSpaceship}"/>
            <DataGridTextColumn Header="Name"
                                Binding="{Binding SpaceshipName}"
                                Width="*"/>
            <DataGridTextColumn Header="Pilot ID"
                                Binding="{Binding PilotId}">
            </DataGridTextColumn>
        </DataGrid.Columns>
    </DataGrid>
</TabControl>

ViewModel相关代码 #

ISpaceShip接口 #

public interface ISpaceShip : ISignalModifBase
// ISignalModifBase继承自INotifyPropertyChanged；其实现包含一个管理标准set方法逻辑的方法
{
    string NumSpaceship { get; set; }
    string SpaceshipName { get; set; }
    string PilotId { get; set; }
}

SpaceShip实现类 #

public class SpaceShip : SignalModifBase, ISpaceShip
{
    public string NumSpaceship { get; set; }

    public string SpaceshipName { get; set; }

    private string _strPilotId = "";
    public string PilotId
    {
        get => _strPilotId;
        set => ManagePropertyChange(ref _strPilotId, value); 
        // ManagePropertyChange是SignalModifBase中的方法，负责设置属性值并触发PropertyChanged事件，符合Binding要求
    }
}

IHRManagement接口 #

public interface IHRManagement : IBaseModule
// IBaseModule继承自ISignalModifBase，后者又继承自INotifyPropertyChanged
{
    ObservableCollection<ISpaceShip> AvailableSpaceships { get; set; }

    ISpaceShip CurrentSpaceship { get; set; }

    bool AssignPilots();
}

HRManagement实现类 #

public class HRManagement : BaseModule, IHRManagement
{
    private ObservableCollection<ISpaceShip> _obcAvailableSpaceships = new();
    public ObservableCollection<ISpaceShip> AvailableSpaceships
    {
        get => _obcAvailableSpaceships;
        set => ManagePropertyChange(ref _obcAvailableSpaceships, value);
    }

    private ISpaceShip? _objCurrentSpaceship = null;
    public ISpaceShip? CurrentSpaceship
    {
        get => _objCurrentSpaceship;
        set => ManagePropertyChange(ref _objCurrentSpaceship, value);
    }

    bool AssignPilots()
    {
        string z_strData;
        StreamReader z_sreData;

        // 初始化z_sreData

        foreach (ISpaceShip z_objShip in AvailableSpaceships)
        {
            CurrentSpaceship = z_objShip;
            string z_strPilotId;
            // 计算当前飞船对应的飞行员ID并赋值给z_strPilotId
            CurrentSpaceship.PilotId = z_strPilotId;
        }
        return true; // 补充原代码缺失的返回值
    }
}

注：省略了部分无关基础设施代码，另有方法可填充AvailableSpaceships集合。

点击btnAssignPilot按钮前，DataGrid的Pilot ID列为空；点击按钮后，该列未逐个更新单元格，仅在AssignPilots方法执行完毕（或调试时跳转到方法末尾）时才全部填充。我希望实现单元格逐个实时更新，已尝试为ItemsSource的Binding添加Mode=OneWay但无效，请问遗漏了什么？

核心原因 #

AssignPilots方法在UI线程同步执行，WPF的UI刷新机制会合并同一线程内的批量属性变更，直到当前任务执行完毕才统一刷新界面，因此无法看到逐个更新的效果。

具体解决步骤 #

1. 将AssignPilots改为异步方法 #

通过异步执行让UI线程在每次更新后有机会处理刷新请求：

// 先修改接口定义
public interface IHRManagement : IBaseModule
{
    // ...其他成员
    Task<bool> AssignPilotsAsync(); // 替换原有的bool AssignPilots()
}

// 实现类修改
public class HRManagement : BaseModule, IHRManagement
{
    // ...其他成员

    public async Task<bool> AssignPilotsAsync()
    {
        string z_strData;
        StreamReader z_sreData;

        // 初始化z_sreData

        foreach (ISpaceShip z_objShip in AvailableSpaceships)
        {
            CurrentSpaceship = z_objShip;
            string z_strPilotId;
            // 计算当前飞船对应的飞行员ID并赋值给z_strPilotId
            CurrentSpaceship.PilotId = z_strPilotId;

            // 让出UI线程，允许界面刷新
            await Task.Yield();
            // 如果需要更明显的逐个更新效果，可添加短延迟：
            // await Task.Delay(100);
        }
        return true;
    }
}

2. 确保命令支持异步执行 #

如果你的AssignPilotCommand基于ICommand实现，需要改成支持异步的版本，示例实现如下：

public class AsyncRelayCommand : ICommand
{
    private readonly Func<Task> _execute;
    private readonly Func<bool>? _canExecute;
    private bool _isExecuting;

    public event EventHandler? CanExecuteChanged;

    public AsyncRelayCommand(Func<Task> execute, Func<bool>? canExecute = null)
    {
        _execute = execute ?? throw new ArgumentNullException(nameof(execute));
        _canExecute = canExecute;
    }

    public bool CanExecute(object? parameter)
    {
        return !_isExecuting && (_canExecute?.Invoke() ?? true);
    }

    public async void Execute(object? parameter)
    {
        if (!CanExecute(parameter)) return;
        _isExecuting = true;
        RaiseCanExecuteChanged();
        try
        {
            await _execute();
        }
        finally
        {
            _isExecuting = false;
            RaiseCanExecuteChanged();
        }
    }

    private void RaiseCanExecuteChanged()
    {
        CanExecuteChanged?.Invoke(this, EventArgs.Empty);
    }
}

在JobManagingInstance中初始化命令时使用该异步版本：

public ICommand AssignPilotCommand { get; }

// 初始化逻辑
AssignPilotCommand = new AsyncRelayCommand(() => HRManagementInstance.AssignPilotsAsync());

3. 确认PropertyChanged事件正确触发 #

确保ManagePropertyChange方法在设置PilotId时，正确传递属性名称（如nameof(PilotId)）并触发PropertyChanged事件，这是WPF绑定实时更新的基础。

内容的提问来源于stack exchange，提问作者Jean-David Lanz