c# - WPF:从 DataGrid.RowDetailsTemplate 获取指定控件的所有列表

Question

我有主要的 DataGrid 用于显示文档列表。 此 MainGrid 具有在 XAML 中指定的 DataGrid.RowDetailsTemplate。

此 DataGrid.RowDetailsTemplate 包含一个(内部或嵌套的)DataGrid。

所以 MainGrid 的每一行都包含 DataGrid.RowDetailsTemplate 和内部 DataGrid。

我需要获取仅具有 MainGrid 引用的所有内部(嵌套)DataGrid 的列表。 我试过 Visual/Logil Tree 助手，但两者都没有为 GetChildren 调用返回任何内容...

从DataGrid.RowDetails获取嵌套DataGrid的方法是什么？

复现步骤: 1) 在 Visual Studio 2013 或更高版本中创建 Windows 桌面 -> WPF 应用程序(空) 2) 使用下面的代码示例:

主窗口.xaml

<Window x:Class="ExampleNestedGrid.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>

        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <ToolBar Grid.Row="0" Header="Action:">
            <Button x:Name="RefreshBtn" Command="{Binding RefreshCommand}">Refresh</Button>
        </ToolBar>

        <DataGrid x:Name="MainGrid" ItemsSource="{Binding Documents}" AutoGenerateColumns="False" Grid.Row="1">
            <DataGrid.Columns>
                <DataGridTextColumn Binding="{Binding Name, Mode=OneWay}" Width="*"/>
                <DataGridTextColumn Binding="{Binding Number, Mode=OneWay}" Width="*"/>
            </DataGrid.Columns>

            <DataGrid.RowDetailsTemplate>
                <DataTemplate>
                    <Grid>
                        <DataGrid x:Name="NestedGrid" ItemsSource="{Binding LinkedEmployees}" AutoGenerateColumns="False">
                            <DataGrid.Columns>
                                <DataGridTextColumn Binding="{Binding Id, Mode=OneWay}" Width="150"/>
                                <DataGridTextColumn Binding="{Binding Name, Mode=OneWay}" Width="150"/>
                                <DataGridTextColumn Binding="{Binding Status, Mode=OneWay}" Width="150"/>
                            </DataGrid.Columns>
                        </DataGrid>
                    </Grid>
                </DataTemplate>
            </DataGrid.RowDetailsTemplate>
        </DataGrid>
    </Grid>
</Window>

主窗口.xaml.cs

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace ExampleNestedGrid
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            DataContext = new DisplayViewModel(MainGrid);
        }
    }

    public class DisplayViewModel : PropertyBase
    {
        private DataGrid MainGrid;

        public DisplayViewModel(DataGrid MainGrid) 
        {
            this.MainGrid = MainGrid;

            Documents = new ObservableCollection<Document>();
            LinkedEmployee empl1 = new LinkedEmployee("1", "Ben");
            LinkedEmployee empl2 = new LinkedEmployee("2", "John");

            Document doc = new Document("first", "111");
            doc.LinkedEmployees.Add(empl1);
            doc.LinkedEmployees.Add(empl2);

            Documents.Add(doc);

            RefreshCommand = new RefreshCommand(Documents, MainGrid);
        }

        public ObservableCollection<Document> Documents { get; set; }
        public ICommand RefreshCommand { get; set; }
    }

    public sealed class LinkedEmployee : PropertyBase
    {
        public LinkedEmployee(string id, string name)
        {
            _id = id;
            _name = name;
        }

        public void Update(string name)
        {
            Name = name;
        }

        private string _id;
        private string _name;
        private bool _status;

        public bool Status 
        {
            get { return _status; }
            set
            {
                _status = value;
                OnPropertyChanged();
            }
        }

        public string Id
        {
            get { return _id; }
            set
            {
                _id = value;
                OnPropertyChanged();
            }
        }

        public string Name
        {
            get { return _name; }
            set
            {
                _name = value;
                OnPropertyChanged();
            }
        }
    }

    public class Document : PropertyBase
    {
        public Document(string name, string number)
        {
            _name = name;
            _number = number;

            LinkedEmployees = new ObservableCollection<LinkedEmployee>();
        }

        public void Update(string number)
        {
            Number = number;
        }

        private string _name;
        private string _number;

        public virtual string Name
        {
            get { return _name; }
            set
            {
                _name = value;
                OnPropertyChanged();
            }
        }

        public virtual string Number
        {
            get { return _number; }
            set
            {
                _number = value;
                OnPropertyChanged();
            }
        }

        public ObservableCollection<LinkedEmployee> LinkedEmployees { get; set; }
    }

    public abstract class PropertyBase : INotifyPropertyChanged
    {
        #region public properties
        public event PropertyChangedEventHandler PropertyChanged;
        #endregion

        #region protected methods
        protected void OnPropertyChanged([CallerMemberName]string caller = null)
        {
            if (PropertyChanged != null)
                PropertyChanged.Invoke(this, new PropertyChangedEventArgs(caller));
        }
        #endregion
    }
}

刷新命令.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Input;
using System.Windows.Media;

namespace ExampleNestedGrid
{
    public class RefreshCommand : ICommand
    {
        private ObservableCollection<Document> Documents;
        private System.Windows.Controls.DataGrid MainGrid;

        #region public methods
        public event EventHandler CanExecuteChanged
        {
            add { CommandManager.RequerySuggested += value; }
            remove { CommandManager.RequerySuggested -= value; }
        }
        #endregion

        #region public methods

        public RefreshCommand(ObservableCollection<Document> Documents, System.Windows.Controls.DataGrid MainGrid)
        {
            // TODO: Complete member initialization
            this.Documents = Documents;
            this.MainGrid = MainGrid;
        }

        public void Execute(object parameter)
        {
            Documents.First().LinkedEmployees.First().Status = !Documents.First().LinkedEmployees.First().Status;

            ICollectionView view = CollectionViewSource.GetDefaultView(Documents);
            view.Filter = (item) => item != null;

            MainGrid.ItemsSource = view;

            var childGrids = FindVisualChildren<DataGrid>(MainGrid);
            foreach (DataGrid childGrid in childGrids)
            {
                MessageBox.Show(childGrid.Name);
            }
        }

        public bool CanExecute(object parameter)
        {
            return Documents != null && MainGrid != null;
        }
        #endregion

        private static IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
        {
            if (depObj != null)
            {
                for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
                {
                    DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
                    if (child != null && child is T)
                    {
                        yield return (T)child;
                    }

                    foreach (T childOfChild in FindVisualChildren<T>(child))
                    {
                        yield return childOfChild;
                    }
                }
            }
        }
    }
}

3) 开始申请。单击第一行。行详细信息应展开。

4) 按第一列对主行进行排序

5) 按第二列对行详细信息进行排序

6) 点击刷新按钮

7) 检查排序指示器是否消失。

8) 检查没有出现应该触发有关找到的嵌套数据网格的消息框。

Answer 1

您只能获取对 RowDetailsTemplate 中当前可见元素的引用。试试这个:

private void Button_Click(object sender, RoutedEventArgs e)
{
    var childGrids = FindVisualChildren<DataGrid>(MainGrid);
    foreach (DataGrid childGrid in childGrids)
    {
        //...
    }
}

private static IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
{
    if (depObj != null)
    {
        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
        {
            DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
            if (child != null && child is T)
            {
                yield return (T)child;
            }

            foreach (T childOfChild in FindVisualChildren<T>(child))
            {
                yield return childOfChild;
            }
        }
    }
}

编辑:如果您重置其ItemsSource，则调用DataGrid 的UpdateLayout() 方法。如果我在父 DataGrid 中选择一行并单击“刷新”按钮，则该命令的 Execute 方法的实现对我有用:

public void Execute(object parameter)
{
    Documents.First().LinkedEmployees.First().Status = !Documents.First().LinkedEmployees.First().Status;

    ICollectionView view = CollectionViewSource.GetDefaultView(Documents);
    view.Filter = (item) => item != null;

    MainGrid.ItemsSource = view;
    MainGrid.UpdateLayout();

    List<DataGrid> childGrids = new List<DataGrid>();
    foreach (var item in MainGrid.Items)
    {
        var container = MainGrid.ItemContainerGenerator.ContainerFromItem(item) as DataGridRow;
        if (container != null)
        {
            childGrids.AddRange(FindVisualChildren<DataGrid>(container));
        }
    }
}