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问WPF:当子DataGrid列中的值和发生变化时，更新主DataGrid行中的单元格值
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Stack Overflow用户

提问于 2020-02-13 21:59:44

回答 1查看 380关注 0票数 0

我有一个主DataGrid (绑定到ObservableCollection<MainItem>)，在RowDetailsTemplate中定义了另一个子DataGrid (绑定到ObservableCollection<SubItem>)。MainItem.Total属性只是返回SubItems.Sum(s => s.Amount)的派生值。这对显示网格非常有用。

但是，如果更改了SubItem.Amount列中的值并更新了MainItem.Total值，尽管MainItem.Total值是正确的(它只是一个派生值)，主网格不会刷新以显示新值。如果强制使用MainDataGrid.Items.Refresh() (例如，在MainDataGrid_SelectedCellsChanged中)，那么主网格就会在MainItem.Total中显示这个值。因此，这是可行的，但它闻起来很难闻，因为它是一种刷新主网格中所有可见行的蛮力方法。[注意:这种情况类似于文章Update single row in a WPF Datagrid，但我已经在使用ObservableCollection了。]

我认为这种行为是因为这种变化发生在ObservableCollection<SubItem>中，而不是在ObservableCollection<MainItem>中，所以它不知道吗？但是，我还没有找到一个可以通知主网格绑定MainItem.Total的内容已经更新的事件。

注意:下面的代码是一个独立的示例，以防有人想要构建并尝试它。这是基于相同的情况，在我的真实项目。

XAML：

<Window x:Class="WpfAppDataGrid.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfAppDataGrid"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="100" />
        </Grid.ColumnDefinitions>
        <DataGrid x:Name="MainDataGrid" Grid.Column="0"
                  ItemsSource="{Binding MainItems}"
                  RowDetailsVisibilityMode="VisibleWhenSelected"
                  SelectedCellsChanged="MainDataGrid_SelectedCellsChanged"
                  AutoGenerateColumns="False"
                  CanUserSortColumns="True"
                  CanUserAddRows="True"
                  CanUserDeleteRows="True"
                  RowBackground="AliceBlue"
                  HorizontalAlignment="Stretch"
                  VerticalAlignment="Stretch"
                  Margin="10,10,10,10">
            <DataGrid.RowDetailsTemplate>
                <DataTemplate>
                    <DataGrid x:Name="SubDataGrid" ItemsSource="{Binding SubItems}"
                              CellEditEnding="SubDataGrid_CellEditEnding"
                              AutoGenerateColumns="False"
                              CanUserAddRows="True"
                              CanUserDeleteRows="True"
                              RowBackground="Bisque">
                        <DataGrid.Columns>
                            <DataGridTextColumn Header="Candidate" Binding="{Binding Candidate}" />
                            <DataGridTextColumn Header="Primary" Binding="{Binding Primary}" />
                            <DataGridTextColumn Header="Amount" Binding="{Binding Amount, StringFormat=\{0:N2\}}" />
                            <DataGridTextColumn Header="Previous" Binding="{Binding Previous}" />
                            <DataGridTextColumn Header="Party" Binding="{Binding Party}" />
                        </DataGrid.Columns>
                    </DataGrid>
                </DataTemplate>
            </DataGrid.RowDetailsTemplate>
            <DataGrid.Columns>
                <DataGridTextColumn Header="Voter" Binding="{Binding Voter}" />
                <DataGridTemplateColumn Header="Date" Width="100" SortMemberPath="Date" >
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding RecordedDate, StringFormat=\{0:MM/dd/yyyy\}}" />
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                    <DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                            <DatePicker SelectedDate="{Binding RecordedDate}" />
                        </DataTemplate>
                    </DataGridTemplateColumn.CellEditingTemplate>
                </DataGridTemplateColumn>
                <DataGridTextColumn Header="Status" Binding="{Binding Status}" />
                <DataGridTextColumn Header="Auto" Binding="{Binding Total, StringFormat=\{0:N2\}}" IsReadOnly="True" >
                    <DataGridTextColumn.CellStyle>
                        <Style>
                            <Setter Property="TextBlock.TextAlignment" Value="Right" />
                        </Style>
                    </DataGridTextColumn.CellStyle>
                </DataGridTextColumn>
            </DataGrid.Columns>
        </DataGrid>
        <StackPanel Grid.Column="1" Margin="10,10,10,10">
            <Button Content="Refresh" Click="Button_Click" />
        </StackPanel>
    </Grid>
</Window>

查看代码-隐藏：

using System.Linq;
using System.Windows;
using System.Windows.Controls;

namespace WpfAppDataGrid
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        enum SubDataGridColumn
        {
            Candidate,
            Primary,
            Amount,
            Previous,
            Party
        }

        private static MainViewModel vm = new MainViewModel();
        private static bool subAmountChanged = false;

        public MainWindow()
        {
            DataContext = vm;
            InitializeComponent();
        }

        private void SubVerifyEdit(SubItem sub, int column, string txt)
        {
            switch ((SubDataGridColumn)column)
            {
                case SubDataGridColumn.Candidate:
                    if (sub.Candidate != txt)
                        sub.Candidate = txt;
                    break;
                case SubDataGridColumn.Primary:
                    if (sub.Primary != txt)
                        sub.Primary = txt;
                    break;
                case SubDataGridColumn.Amount:
                    var amount = decimal.Parse(txt);
                    if (sub.Amount != amount)
                    {
                        sub.Amount = amount;
                        subAmountChanged = true;
                    }
                    break;
                case SubDataGridColumn.Party:
                    if (sub.Party != txt)
                        sub.Primary = txt;
                    break;
                case SubDataGridColumn.Previous:
                    if (sub.Previous != txt)
                        sub.Previous = txt;
                    break;
                default:
                    break;
            }
        }

        private void SubDataGrid_CellEditEnding(object sender, DataGridCellEditEndingEventArgs e)
        {
            var sub = (SubItem)e.Row.Item;
            var column = e.Column.DisplayIndex;
            var dep = (DependencyObject)e.EditingElement;
            if (dep is TextBox)
            {
                SubVerifyEdit(sub, column, ((TextBox)dep).Text);
            }
            else if (dep is ComboBox)
            {
                SubVerifyEdit(sub, column, ((ComboBox)dep).SelectedItem.ToString());
            }
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            MainDataGrid.Items.Refresh();
        }

        private void MainDataGrid_SelectedCellsChanged(object sender, SelectedCellsChangedEventArgs e)
        {
            if (subAmountChanged)
            {
                //var main = (MainItem)MainDataGrid.CurrentItem;  
                //var sum = main.SubItems.Sum(s => s.Amount);
                //var manual = main.ManualTotal;
                //var auto = main.AutoTotal;

                //var dep = (DependencyProperty)MainDataGrid.CurrentItem;
                //MainDataGrid.CoerceValue(dep);
                MainDataGrid.Items.Refresh();
                subAmountChanged = false;
            }
        }
    }
}

ViewModel：

using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;

namespace WpfAppDataGrid
{
    public class MainViewModel : INotifyPropertyChanged
    {

        public event PropertyChangedEventHandler PropertyChanged;

        public MainViewModel()
        {
            MainItems = new ObservableCollection<MainItem>();

            MainItems.Add(new MainItem("Thomas", DateTime.Now, "Unsure"));
            MainItems[0].SubItems.Add(new SubItem("Roberts", "NH", 27.46m, "Senator", "Republican"));

            MainItems.Add(new MainItem("Arthur", DateTime.Now, "No worries"));
            MainItems[1].SubItems.Add(new SubItem("Johnson", "IA", 47.5m, "Representative", "Republican"));
            MainItems[1].SubItems.Add(new SubItem("Butegieg", "CA", 76.42m, "Senator", "Democrat"));
            MainItems[1].SubItems.Add(new SubItem("Warren", "SC", 14.5m, "Governor", "Democrat"));

            MainItems.Add(new MainItem("Cathy", DateTime.Now, "What now"));
            MainItems[2].SubItems.Add(new SubItem("Biden", "WI", 1456.98m, "Mayor", "Democrat"));

            MainItems.Add(new MainItem("Jonathan", DateTime.Now, "Got this"));
            MainItems[3].SubItems.Add(new SubItem("Foobar", "MI", 5672.3m, "None", "Republican"));
            MainItems[3].SubItems.Add(new SubItem("Sanders", "ME", 1.45m, "Senator", "Democrat"));

            MainItems.Add(new MainItem("Roger", DateTime.Now, "Still undecided"));
            MainItems[4].SubItems.Add(new SubItem("Wakemeyer", "AK", 56m, "Police Chief", "Democrat"));
            MainItems[4].SubItems.Add(new SubItem("Trump", "FL", 982.34m, "Businessman", "Republican"));
        }

        private void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        private ObservableCollection<MainItem> mainItems;
        public ObservableCollection<MainItem> MainItems
        {
            get { return mainItems; }
            set
            {
                mainItems = value;
                NotifyPropertyChanged();
            }
        }
    }
}

MainItem类：

using System;
using System.Collections.ObjectModel;
using System.Linq;

namespace WpfAppDataGrid
{
    public class MainItem
    {
        public MainItem() { }

        public MainItem(string voter, DateTime date, string status)
        {
            Voter = voter;
            RecordedDate = date;
            Status = status;
        }

        public string Voter { get; set; }
        public DateTime RecordedDate { get; set; }
        public string Status { get; set; }
        public decimal Total { get { return SubItems.Sum(s => s.Amount); } }
        public ObservableCollection<SubItem> SubItems { get; set; } = new ObservableCollection<SubItem>();
    }
}

SubItem类：

namespace WpfAppDataGrid
{
    public class SubItem
    {
        public SubItem() { }

        public SubItem(string candidate, string primary, decimal amount, string previous, string party)
        {
            Candidate = candidate;
            Primary = primary;
            Amount = amount;
            Previous = previous;
            Party = party;
        }

        public string Candidate { get; set; }
        public string Primary { get; set; }
        public decimal Amount { get; set; }
        public string Previous { get; set; }
        public string Party { get; set; }
    }
}

datagrid

wpf

回答 1

Stack Overflow用户

回答已采纳

发布于 2020-02-14 13:36:42

MainItem和SubItem都应该实现INotifyPropertyChanged。

当更改PropertyChanged属性时，后者应引发Amount事件，而MainItem类则需要为SubItems中的所有SubItem对象订阅PropertyChanged事件，并在更改其中任何一个SubItem对象时为Total属性引发PropertyChanged事件：

public class MainItem : INotifyPropertyChanged
{
    public MainItem()
    {
        SubItems.CollectionChanged += SubItems_CollectionChanged;
    }

    public MainItem(string voter, DateTime date, string status)
    {
        Voter = voter;
        RecordedDate = date;
        Status = status;
        SubItems.CollectionChanged += SubItems_CollectionChanged;
    }

    private void SubItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
        if (e.NewItems != null)
        {
            foreach (object subItem in e.NewItems)
            {
                (subItem as INotifyPropertyChanged).PropertyChanged
                    += new PropertyChangedEventHandler(item_PropertyChanged);
                item_PropertyChanged(sub, new PropertyChangedEventArgs(nameof(Total)));
            }
        }

        if (e.OldItems != null)
        {
            foreach (object country in e.OldItems)
            {
                item_PropertyChanged(sub, new PropertyChangedEventArgs(nameof(Total)));
                (subItem as INotifyPropertyChanged).PropertyChanged
                    -= new PropertyChangedEventHandler(item_PropertyChanged);
            }
        }
    }

    private void item_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        NotifyPropertyChanged(e.PropertyName);
    }

    public string Voter { get; set; }
    public DateTime RecordedDate { get; set; }
    public string Status { get; set; }
    public decimal Total { get { return SubItems.Sum(s => s.Amount); } }
    public ObservableCollection<SubItem> SubItems { get; set; } = new ObservableCollection<SubItem>();


    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

票数 1

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/60217101

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