ObservableCollection<Entity>。属性在更改后不更新UI

我有这个 DataGrid

<DataGrid ItemsSource="{Binding Consignments}" 
            SelectedItem="{Binding SelectedConsignment}"
            x:Name="dataGridConsignments" 
            Margin="10,47,10,9.6"
            IsReadOnly="True" ColumnWidth="*" AutoGenerateColumns="False"
            clr:Commands.DataGridDoubleClickCommand="{Binding DataGridDoubleClick}">

    <DataGrid.Columns>
        <DataGridTextColumn Header="Name" Binding="{Binding ConsignmentId,UpdateSourceTrigger=PropertyChanged}"></DataGridTextColumn>
        <DataGridTextColumn Header="Created" Binding="{Binding CreatedDate}"></DataGridTextColumn>
        <DataGridTextColumn Header="Weight" Binding="{Binding TotalWeight, StringFormat=N2}"></DataGridTextColumn>
    </DataGrid.Columns>

在我的心里 ViewModel :

private ObservableCollection<Consignment> consignments;
public ObservableCollection<Consignment> Consignments { get { return consignments; } set { consignments = value; OnPropertyChanged("Consignments"); } }

数据网格 并更新这些项目的ID,以便没有间隙(ID应为1,2,3,4…),因此我有以下命令:

private ICommand removeConsignment;
public ICommand RemoveConsignment
{
    get
    {
        return removeConsignment
            ?? (removeConsignment = new ActionCommand(() =>
            {
                var c = SelectedConsignment;
                StandardDatabase.Commands.RemoveConsignment(c.Id);
                Consignments = new ObservableCollection<Consignment>(db.Consignments.ToList());
            }));
    }
}

Commands.RemoveConsignment 更新db中的所有内容,但UI保持不变(例如,如果删除项2,则ID为1、3、4…)。

• 如你所见,我试着添加 INotifyPropertyChanged 到 ObersvableCollection 但这不起作用。

• 我想我可以把这个加到 ConsignmentId 属性,但我不认为这是可取的?

• 我甚至直接从数据库重新创建了这个集合,但不知怎么的,它仍然不起作用。。即使在浏览到不同的页面并返回

• 另一种选择是包装 Consignment 在一个 ConsignmentViewModel 对象—我以前在这方面已经取得了一些成功—但我的理解是,遵循MVVM之后,我应该只操纵 托运 PageConsignmentsViewModel

如果有人能提供建议,我将不胜感激

public static void RemoveConsignment(int id)
{
    using (var db = new ApplicationDbContext())
    {
        var consignment = db.Consignments.SingleOrDefault(p => p.Id == id);

        db.Consignments.Remove(consignment);

        // Reset consignmentIds
        for (int i = consignment.ConsignmentId ; i < db.Consignments.Count(); i++)
        {
            var c = db.Consignments.SingleOrDefault(x => x.ConsignmentId == i + 1);
            c.ConsignmentId = c.ConsignmentId - 1;
            db.Entry(c).CurrentValues.SetValues(c);
        }

        db.SaveChanges();
    }
}

public class Consignment : EntityBase
{
    public virtual Order Order { get; set; }

    public virtual ICollection<Package> Packages { get; set; }
    public virtual int ConsignmentId { get; set; }

    public Consignment()
    {
        Packages = new HashSet<Package>();
    }

    [NotMapped]
    public double TotalWeight
    {
        get
        {
            return Packages.ToList().Sum(p => p.PartQuantities.Sum(pq => pq.UnitWeight * pq.Quantity));
        }
    }
}