在 mvvm wpf c# 中将属性从一个视图模型传递到另一个视图模型

Question

尝试将一个视图模型中的 wpf 数据网格中的选定行传递到另一个视图模型进行编辑。我可以选择该行并将其放入属性中。但无法将其传递给不同视图模型中的另一个属性。

这是选择行的视图模型中的代码：

using Checkbook8.Data;

using System.Collections.ObjectModel;

namespace Checkbook8.Views
{
    internal class ChkbkTransactionListViewModel : BindableBase
    {
        private ObservableCollection<ChkbkTransaction>? _ChkbkRecordCol;

        public ChkbkTransactionListViewModel()
        {
            GetData();
        }

        private void GetData()
        {
            using (var context = new ChkbkTransactionDbContext())
            {
                _ChkbkRecordCol = new ObservableCollection<ChkbkTransaction>   (context.ChkbkTransactions.ToList());
            }
        }

        public ObservableCollection<ChkbkTransaction>? ChkbkRecordCol
        {
            get => _ChkbkRecordCol;
            set => SetProperty(ref _ChkbkRecordCol, value);
        }

        private static ChkbkTransaction? _SelectedTransaction;
        public ChkbkTransaction? SelectedTransaction
        {
            get => _SelectedTransaction;
            set => SetProperty(ref _SelectedTransaction, value);
        }

        private static ChkbkTransactionListViewModel _Instance = new();
        public static ChkbkTransactionListViewModel Instance { get {  return _Instance; } }

    }
}

这是我尝试将 SelectedTransaction 属性传递给的代码：

using Checkbook8.Data;

namespace Checkbook8.Views
{
    internal class EditTransactionViewModel : BindableBase
    {
        private ChkbkTransaction _TransactionSelected;
        public ChkbkTransaction TransactionSelected
        {
            get => _TransactionSelected;
            set
            {
                value = ChkbkTransactionListViewModel.Instance.SelectedTransaction;
                SetProperty(ref _TransactionSelected, value);
            }
        }
    }
}

我做错了什么？

Answer 1

EditTransactionViewModel.TransactionSelected

的设置者有点不寻常。它似乎从未被调用过，并且忽略了传入的值，这确实很奇怪。因此，您可能只需删除 setter 并保留可编辑的

TransactionSelected

属性 与

ChkbkTransactionListViewModel

中的同步。
这是一种方法：

internal class EditTransactionViewModel : BindableBase
{
    public EditTransactionViewModel()
    {
        ChkbkTransactionListViewModel.Instance.PropertyChanged += (o, e) => 
        {
            if (e.PropertyName == nameof(ChkbkTransactionListViewModel.TransactionSelected)
            {
              SetProperty(ref _TransactionSelected,
                    ChkbkTransactionListViewModel.Instance.TransactionSelected);
            }
        }
    }

    private ChkbkTransaction _TransactionSelected;
    public ChkbkTransaction TransactionSelected => _TransactionSelected;
}