在 DataTable 中显示已删除的行

Question

所以我有一个 DataTable 绑定到 XAML 中的 DataGrid。 允许用户添加、修改和删除表的行。我想用特定颜色标记行，具体取决于用户所做的操作。例如，如果用户添加一行，该行将被标记为绿色。如果用户修改了一行，则该行将被标记为橙色。如果用户删除该行，该行将被标记为红色。 我遇到的问题是，一旦我从视图模型中调用row.Delete();，删除的行就不再可见。

有没有办法让DataRow 在DataGrid 中显示为要删除？我知道如何实现行背景效果，具体取决于用户操作。唯一的问题是我不知道如何保持已删除的行可见。这个想法是用户可以恢复更改或应用它们，这就是应该实际删除待删除行的时候。

编辑（添加了关于如何更新行背景颜色的示例）：

<MultiDataTrigger>
    <MultiDataTrigger.Conditions>
        <Condition Binding="{Binding Path=Row.RowState}" Value="{x:Static data:DataRowState.Deleted}" />
        <Condition Binding="{Binding RelativeSource={RelativeSource Mode=Self}, Path=IsSelected}" Value="False" />
    </MultiDataTrigger.Conditions>
    <MultiDataTrigger.Setters>
        <Setter Property="Background" Value="IndianRed" TargetName="DGR_Border"/>
        <Setter Property="Foreground" Value="Black"/>
        <Setter Property="FontWeight" Value="Bold"/>
    </MultiDataTrigger.Setters>
</MultiDataTrigger>

Answer 1

我认为，当用户标记要删除的行时 - 您应该将其保存在某处的索引（例如int[] 数组或List<int>），然后在用户完成使用表时为该集合中的每个元素调用yourDataGridView.Rows.RemoveAt(index)。

可能是这样的：

//Collection for rows indexes which will be deleted later
List<int> rowsToDelete = new List<int>();

//Call this when user want to delete element
private void MarkElementsToRemove()
{
   if (yourDataGrid.SelectedItems.Count > 0)
   {
       //Get selected by user rows
       for (int i = 0; i < yourDataGrid.SelectedItems.Count; ++i)
       {
           DataGridRow row = (DataGridRow)yourDataGrid.SelectedItems[i];

           //Fill rows background with some color to mark them visually as "deleted"
           row.Background = new SolidColorBrush(Color.FromRgb(255, 0, 0));

           //Get row index to remove it later and add it to collection
           rowsToDelete.Add(row.GetIndex());                        
        }
    }
}

// Call this when user finished work with DataGrid and items may be removed
private void RemoveMarkedElements()
{
   foreach (int index in rowsToDelete)
   {
      yourDataGrid.Items.RemoveAt(index);
   }
   
   rowsToDelete.Clear();
}

您可以保存整个 DataGridRow 并调用 yourDataGrid.Remove(wholeRow);，而不是索引。 而对于反向删除，您只需通过删除颜色并从集合中删除行索引或整行来取消标记。

Answer 2

如果我理解正确，您需要使用 Delete 键，而不是删除行，而是在它们上放置一个标记。 在 DataGrid 中，您需要突出显示用此标记标记的行的颜色。 你没有展示你的桌子，所以我将在我的简单调解中展示。

示例使用BaseInpc and RelayCommand classes。

除此之外，使用命令扩展方式：

using System.Windows.Input;

namespace Simplified
{
    public static class CommandExtensionMethods
    {
        public static bool TryExecute(this ICommand command, object parameter)
        {
            bool can = command.CanExecute(parameter);
            if (can)
                command.Execute(parameter);
            return can;
        }
        public static bool TryExecute(this ICommand command)
          => TryExecute(command, null);
  }

}

视图模型：

using Simplified;
using System.Data;
using System.Windows.Input;

namespace DeferredRowDeletion
{
    public class DrdViewModel : BaseInpc
    {
        public DataTable Table { get; } = new DataTable();
        public DrdViewModel()
        {
            Table.Columns.Add("Name", typeof(string));
            Table.Columns.Add("Value", typeof(int));
            Table.Columns.Add("Marked for deletion", typeof(bool));
            foreach (var name in new string[] { "First", "Second", "Third", "Fourth", "Fifth" })
            {
                var row = Table.NewRow();
                row[0] = name;
                row[1] = Table.Rows.Count;
                row[2] = Table.Rows.Count % 2 == 1;
                Table.Rows.Add(row);
            }
        }

        private ICommand _markRemoveChangeCommand;
        private bool _isRemoveRowsImmediately;

        public ICommand MarkRemoveChangeCommand => _markRemoveChangeCommand
            ?? (_markRemoveChangeCommand = new RelayCommand<DataRow>(
                row => row[2] = !(bool)(row[2] ?? false),
                row => !IsRemoveRowsImmediately
                ));

        public bool IsRemoveRowsImmediately
        {
            get => _isRemoveRowsImmediately;
            set => Set(ref _isRemoveRowsImmediately, value);
        }
    }
}

窗口 XAML：

<Window x:Class="DeferredRowDeletion.DrdWindow"
        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:DeferredRowDeletion"
        mc:Ignorable="d"
        Title="DrdWindow" Height="450" Width="800">
    <FrameworkElement.DataContext>
        <local:DrdViewModel/>
    </FrameworkElement.DataContext>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <CheckBox Content="Removw Rows Immediately"
                  IsChecked="{Binding IsRemoveRowsImmediately}"
                  Margin="5"/>
        <DataGrid x:Name="dataGrid" Grid.Row="1"
                  ItemsSource="{Binding Table, Mode=OneWay}"
                  AutoGeneratingColumn="OnAutoGeneratingColumn"
                  CanUserDeleteRows="{Binding IsRemoveRowsImmediately}"
                  PreviewKeyDown="OnPreviewKeyDown">
            <DataGrid.RowStyle>
                <Style TargetType="DataGridRow">
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding [Marked for deletion]}" Value="true">
                            <Setter Property="Background" Value="HotPink"/>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </DataGrid.RowStyle>
        </DataGrid>
    </Grid>
</Window>

窗口后面的代码：

using Simplified;
using System.Data;
using System.Windows;
using System.Windows.Input;

namespace DeferredRowDeletion
{
    public partial class DrdWindow : Window
    {
        public DrdWindow()
        {
            InitializeComponent();
        }
        private void OnAutoGeneratingColumn(object sender, System.Windows.Controls.DataGridAutoGeneratingColumnEventArgs e)
        {
            if (e.PropertyName == "Marked for deletion")
                e.Cancel = true;
        }

        private void OnPreviewKeyDown(object sender, System.Windows.Input.KeyEventArgs e)
        {
            if (e.Key == Key.Delete)
            {
                DrdViewModel viewModel = (DrdViewModel)DataContext;
                var rowView = dataGrid.CurrentItem as DataRowView;
                if (rowView != null && !rowView.IsEdit)
                    viewModel.MarkRemoveChangeCommand.TryExecute(rowView.Row);
            }
        }
    }
}

如果您无法使用此示例，请写下原因并在问题解释中添加详细信息。

答案由补充细节的说明补充：

我想我应该提到我使用绑定到 DataTrigger 的 DataRow 的 RowState 属性来更新行背景颜色。为问题添加了详细信息。

要控制行的可见性，您需要更改DataTable.DefaultView.RowStateFilter 属性的值。 这在 ViewModel 中并不难做到。

但另一个问题是RowState 属性没有通知其更改。 所以触发器绑定不会像那样工作。 在我的示例中，我通过调用Items.Refresh () 解决了这个问题。 也许您正在使用不同的解决方案，因为您没有写过任何与此相关的问题。

using Simplified;
using System.Data;
using System.Windows.Input;

namespace DeferredRowDeletion
{
    public class ShowDeletedRowsViewModel : BaseInpc
    {
        public DataTable Table { get; } = new DataTable();
        public ShowDeletedRowsViewModel()
        {
            Table.Columns.Add("Name", typeof(string));
            Table.Columns.Add("Value", typeof(int));
            foreach (var name in new string[] { "First", "Second", "Third", "Fourth", "Fifth" })
            {
                var row = Table.NewRow();
                row[0] = name;
                row[1] = Table.Rows.Count;
                Table.Rows.Add(row);
            }
            // Commits all the changes 
            Table.AcceptChanges();

            Table.Rows[1].Delete();
            Table.Rows[3].Delete();

            // Show Deleded Rows
            IsVisibilityDelededRows = true;
        }

        private ICommand _markRemoveChangeCommand;
        private bool _isVisibilityDelededRows;

        public ICommand MarkRemoveChangeCommand => _markRemoveChangeCommand
            ?? (_markRemoveChangeCommand = new RelayCommand<DataRow>(
                row => IsVisibilityDelededRows ^= true,
                row => !IsVisibilityDelededRows
                ));

        public bool IsVisibilityDelededRows
        {
            get => _isVisibilityDelededRows;
            set => Set(ref _isVisibilityDelededRows, value);
        }

        protected override void OnPropertyChanged(string propertyName, object oldValue, object newValue)
        {
            base.OnPropertyChanged(propertyName, oldValue, newValue);

            if (propertyName == nameof(IsVisibilityDelededRows))
            {
                // Change the row filter if the associated property has changed
                if (IsVisibilityDelededRows)
                {
                    Table.DefaultView.RowStateFilter |= DataViewRowState.Deleted;
                }
                else
                {
                    Table.DefaultView.RowStateFilter &= ~DataViewRowState.Deleted;
                }
            }
        }
    }
}

<Window x:Class="DeferredRowDeletion.SdrWindow"
        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:DeferredRowDeletion" xmlns:data="clr-namespace:System.Data;assembly=System.Data"
        mc:Ignorable="d"
        Title="SdrWindow" Height="450" Width="800">
    <FrameworkElement.DataContext>
        <local:ShowDeletedRowsViewModel/>
    </FrameworkElement.DataContext>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <StackPanel>
            <CheckBox x:Name="cbAutoRefresh" Content="Auto Items.Refresh()" IsChecked="True" Margin="5"/>
            <CheckBox Content="Visibility Deleded Rows"
                  IsChecked="{Binding IsVisibilityDelededRows}"
                  Margin="5"/>
        </StackPanel>
        <DataGrid x:Name="dataGrid" Grid.Row="1"
                  ItemsSource="{Binding Table, Mode=OneWay}"
                  PreviewKeyUp="OnPreviewKeyUp">
            <DataGrid.Columns>
                <DataGridTextColumn Binding="{Binding Path=Row.RowState, Mode=OneWay}"
                                    Header="RowState"/>
            </DataGrid.Columns>
            <DataGrid.RowStyle>
                <Style TargetType="DataGridRow">
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding Path=Row.RowState}" Value="{x:Static data:DataRowState.Deleted}">
                            <Setter Property="Background" Value="HotPink"/>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </DataGrid.RowStyle>
        </DataGrid>
    </Grid>
</Window>

        private void OnPreviewKeyUp(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Delete && cbAutoRefresh.IsChecked == true)
                dataGrid.Items.Refresh();
        }