我试图在C# WPF MVVM中单击DataGrid中的按钮后添加另一行。问题是，只要我单击其他位置（例如在TextBox中），该行就会被添加。这意味着DataGrid在单击“添加行”按钮后不会立即更新。

NewDocumentView.xaml

<DataGrid x:Name="DataGrid"
          AutoGenerateColumns="False"
          HorizontalAlignment="Left"
          VerticalAlignment="Top"
          Grid.Row="1"
          Margin="20,350,0,0"
          ItemsSource="{Binding Items}">
    <DataGrid.Columns>
        <DataGridTextColumn Header="Description" Binding="{Binding Description}" Width="500"/>
        <DataGridTextColumn Header="Unit" Binding="{Binding Unit}" Width="100"/>
        <DataGridTextColumn Header="Price" Binding="{Binding Price}" Width="100"/>
        <DataGridTextColumn Header="Total" Binding="{Binding Total}" Width="100"/>
        <DataGridTemplateColumn Header="Actions">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <Button Content="Add Row" Command="{Binding AddItemCommand}" Width="100"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

字符串

NewDocumentViewModel.cs

namespace App.MVVM.ViewModel
{
    internal class NewDocumentViewModel : ObservableObject
    {
        public ObservableCollection<Item> Items { get; set; } = new ObservableCollection<Item>();

        public RelayCommand AddItemCommand { get; set; }

        public NewDocumentViewModel()
        {
            Items = new ObservableCollection<Item>();

            AddItemCommand = new RelayCommand(o => { AddNewItem(); });
        }

        private void AddNewItem()
        {
            Items.Add(new Item());
        }
    }
}

型

NewDocumentView.xaml.cs

namespace App.MVVM.View
{
    public partial class NewDocumentView : UserControl
    {
        public NewDocumentView()
        {
            InitializeComponent();
            DataContext = new NewDocumentViewModel();
        }
    }
}

型

Item.cs

namespace App.MVVM.Model
{
    class Item : ObservableObject
    {
        private string _description;
        public string Description
        {
            get { return _description; }
            set
            {
                if (_description != value)
                {
                    _description = value;
                    OnPropertyChanged(nameof(Description));
                }
            }
        }

        private string _unit;
        public string Unit
        {
            get { return _unit; }
            set
            {
                if (_unit != value)
                {
                    _unit = value;
                    OnPropertyChanged(nameof(Unit));
                }
            }
        }

        private int _price;
        public int Price
        {
            get { return _price; }
            set
            {
                if (_price != value)
                {
                    _price = value;
                    OnPropertyChanged(nameof(Price));
                }
            }
        }

        private int _total;
        public int Total
        {
            get { return _total; }
            set
            {
                if (_total != value)
                {
                    _total = value;
                    OnPropertyChanged(nameof(Total));
                }
            }
        }
    }
}

型

ObservableObject.cs

namespace App.Core
{
    internal class ObservableObject : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler? PropertyChanged;

        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

型

RelayCommand.cs

namespace App.Core
{
    internal class RelayCommand : ICommand
    {
        private readonly Action<object> execute;
        private readonly Func<object, bool> canExecute;

        public RelayCommand(Action<object> execute, Func<object, bool> canExecute = null)
        {
            this.execute = execute;
            this.canExecute = canExecute;
        }

        public event EventHandler CanExecuteChanged
        {
            add => CommandManager.RequerySuggested += value;
            remove => CommandManager.RequerySuggested -= value;
        }

        public bool CanExecute(object parameter)
        {
            return canExecute == null || canExecute(parameter);
        }

        public void Execute(object parameter)
        {
            execute(parameter);
        }
    }
}

型
我做错了什么？我如何使用按钮立即更新DataGrid向DataGrid添加新行？