Question

我已将ReactiveList Orders绑定到wpf中的datagrid。我通过遵循语法

成功获得了一个选定的订单

private Order _selectedOrder;
public Order SelectedOrder
{
    get { return _selectedOrder; }
    set { this.RaiseAndSetIfChanged(ref _selectedOrder, value); }
}
this.WhenAnyValue(x => x.Orders.ItemChanged).Select(x => _selectedOrder = ((Order)x));

但是，如果我在datagrid中多选择订单，我该如何获取所选项目？

Answer 1

您的代码似乎无法执行您想要的操作，因为您似乎正在侦听ReactiveList ItemChanged observable（当数据源发生更改时将触发），当您要监视的是网格选择时。

虽然未经过测试，但以下代码似乎更符合您的目标（使用reactiveui-events助手）：

// in the VM
public IList<Order> SelectedOrders { /* regular RxUI property as usual */ }

// in the view
this.Grid.Events().SelectionChanged
    .Select(_ => this.Grid.SelectedItems.Cast<Order>().ToList())
    .Subscribe(list => ViewModel.SelectedOrders = list);

我是否掌握了你想要达到的目标？

Answer 2

根据Gluck提供的提示，我发现了一种通过在视图中为datagrid添加选择更改事件处理程序来获取所选订单集合的方法，如下所示

在ViewModel中添加反应属性

private IList<Order> selectedOrders;
public IList<Order> SelectedOrders
{
    get
    {
        return selectedOrders;
    }
    set { this.RaiseAndSetIfChanged(ref selectedOrders, value); }
}

并在视图的代码隐藏

中

private void OrdersGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    ViewModel.SelectedOrders = OrdersGrid.SelectedItems.Cast<Order>().ToList();
}

Answer 3

首先，您需要将EventPattern转换为IObservable。您可以使用以下方法进行此操作：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reactive.Linq;
using System.Windows.Controls;

namespace System.Windows.Controls.Extensions
{
    public static class ListBoxExtensions
    {
        public static IObservable<List<T>> SelectionChanged<T>(this ListBox listBox)
        {
            return Observable.FromEventPattern<SelectionChangedEventHandler, SelectionChangedEventArgs>(
                eh => listBox.SelectionChanged += eh,
                eh => listBox.SelectionChanged -= eh)
                .Select(_ => listBox.SelectedItems.Cast<T>().ToList());
        }
    }
}

然后在您的Control中，将结果绑定到ViewModel上，如下所示：

    public partial class MyControl : UserControl, IViewFor<MyViewModel>
    {
        public MyControl()
        {
            InitializeComponent();

            this.WhenActivated(d =>
            {
                MyListView.SelectionChanged<MyItemViewModel>()
                    .Do(list => ViewModel.SelectedItems = list)
                    .SubscribeOn(RxApp.MainThreadScheduler)
                    .ObserveOn(RxApp.MainThreadScheduler)
                    .Subscribe()
                    .DisposeWith(d);
            });
        }

        object IViewFor.ViewModel
        {
            get => ViewModel;
            set => ViewModel = value as MyViewModel;
        }

        public MyViewModel ViewModel
        {
            get => DataContext as MyViewModel;
            set => DataContext = value;
        }
    }

使用ReactiveUI从ReactiveList获取Selected Items集合

3 个答案: