WPF 4 DataGrid：将行号获取到 RowHeader 中

Question

我希望将行号放入 WPF 4 DataGrid 的 RowHeader 中，以便它有一个类似于 Excel 的列用于显示 DataGrid 的行号。

我在网上看到的解决方案建议向业务对象添加索引字段。这并不是一个真正的选择，因为 DataGrid 将被频繁使用，并且我们不想不断跟踪这些索引字段的更改。

多谢

Answer 1

一种方法是将它们添加到 DataGrid 的 LoadingRow 事件中。

<DataGrid Name="DataGrid" LoadingRow="DataGrid_LoadingRow" ... />

void DataGrid_LoadingRow(object sender, DataGridRowEventArgs e)
{
    // Adding 1 to make the row count start at 1 instead of 0
    // as pointed out by daub815
    e.Row.Header = (e.Row.GetIndex() + 1).ToString(); 
}

更新
为了使其能够与 WPF Toolkit 中的 .NET 3.5 DataGrid 一起使用，需要进行一些修改。使用虚拟化时，索引仍然可以正确生成，但输出失败。对 RowHeaderTemplate 的以下修改修复了此

<toolkit:DataGrid LoadingRow="DataGrid_LoadingRow">
    <toolkit:DataGrid.RowHeaderTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding RelativeSource={RelativeSource AncestorType={x:Type toolkit:DataGridRow}},
                                      Path=Header}"/>
        </DataTemplate>
    </toolkit:DataGrid.RowHeaderTemplate>
</toolkit:DataGrid>

编辑 2012-07-05
如果从源列表中添加或删除项目，则数字会不同步，直到滚动列表，从而再次调用 LoadingRow 。解决这个问题有点复杂，我现在能想到的最佳解决方案是保留上面的 LoadingRow 解决方案，并

• 订阅 dataGrid.ItemContainerGenerator.ItemsChanged
• 中在事件处理程序中，找到可视化树中的所有子 DataGridRows
• 将 Header 设置为每个 DataGridRow 的索引

以下是执行此操作的附加行为。像这样使用它

<DataGrid ItemsSource="{Binding ...}"
          behaviors:DataGridBehavior.DisplayRowNumber="True">

DisplayRowNumber

public class DataGridBehavior
{
    #region DisplayRowNumber

    public static DependencyProperty DisplayRowNumberProperty =
        DependencyProperty.RegisterAttached("DisplayRowNumber",
                                            typeof(bool),
                                            typeof(DataGridBehavior),
                                            new FrameworkPropertyMetadata(false, OnDisplayRowNumberChanged));
    public static bool GetDisplayRowNumber(DependencyObject target)
    {
        return (bool)target.GetValue(DisplayRowNumberProperty);
    }
    public static void SetDisplayRowNumber(DependencyObject target, bool value)
    {
        target.SetValue(DisplayRowNumberProperty, value);
    }

    private static void OnDisplayRowNumberChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
    {
        DataGrid dataGrid = target as DataGrid;
        if ((bool)e.NewValue == true)
        {
            EventHandler<DataGridRowEventArgs> loadedRowHandler = null;
            loadedRowHandler = (object sender, DataGridRowEventArgs ea) =>
            {
                if (GetDisplayRowNumber(dataGrid) == false)
                {
                    dataGrid.LoadingRow -= loadedRowHandler;
                    return;
                }
                ea.Row.Header = ea.Row.GetIndex();
            };
            dataGrid.LoadingRow += loadedRowHandler;

            ItemsChangedEventHandler itemsChangedHandler = null;
            itemsChangedHandler = (object sender, ItemsChangedEventArgs ea) =>
            {
                if (GetDisplayRowNumber(dataGrid) == false)
                {
                    dataGrid.ItemContainerGenerator.ItemsChanged -= itemsChangedHandler;
                    return;
                }
                GetVisualChildCollection<DataGridRow>(dataGrid).
                    ForEach(d => d.Header = d.GetIndex());
            };
            dataGrid.ItemContainerGenerator.ItemsChanged += itemsChangedHandler;
        }
    }

    #endregion // DisplayRowNumber

    #region Get Visuals

    private static List<T> GetVisualChildCollection<T>(object parent) where T : Visual
    {
        List<T> visualCollection = new List<T>();
        GetVisualChildCollection(parent as DependencyObject, visualCollection);
        return visualCollection;
    }

    private static void GetVisualChildCollection<T>(DependencyObject parent, List<T> visualCollection) where T : Visual
    {
        int count = VisualTreeHelper.GetChildrenCount(parent);
        for (int i = 0; i < count; i++)
        {
            DependencyObject child = VisualTreeHelper.GetChild(parent, i);
            if (child is T)
            {
                visualCollection.Add(child as T);
            }
            if (child != null)
            {
                GetVisualChildCollection(child, visualCollection);
            }
        }
    }

    #endregion // Get Visuals
}

Answer 2

编辑：显然滚动会更改索引，因此绑定不会像那样工作......

（看似）干净的模板解决方案：
Xaml：

<Window
    ...
    xmlns:local="clr-namespace:Test"
    DataContext="{Binding RelativeSource={RelativeSource Mode=Self}}">
    <Window.Resources>
        <local:RowToIndexConv x:Key="RowToIndexConv"/>
    </Window.Resources>
        <DataGrid ItemsSource="{Binding GridData}">
            <DataGrid.RowHeaderTemplate>
                <DataTemplate>
                    <TextBlock Margin="2" Text="{Binding RelativeSource={RelativeSource AncestorType=DataGridRow}, Converter={StaticResource RowToIndexConv}}"/>
                </DataTemplate>
            </DataGrid.RowHeaderTemplate>
        </DataGrid>
</Window>

转换器：

public class RowToIndexConv : IValueConverter
{

    #region IValueConverter Members

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        DataGridRow row = value as DataGridRow;
        return row.GetIndex() + 1;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }

    #endregion
}

Answer 3

如果添加或删除行，所有这些方法都将不起作用。在这种情况下，您应该刷新行索引。看看这个行为：

public static class DataGridBehavior
{
    #region RowNumbers property

    public static readonly DependencyProperty RowNumbersProperty =
        DependencyProperty.RegisterAttached("RowNumbers", typeof (bool), typeof (DataGridBehavior), 
        new FrameworkPropertyMetadata(false, OnRowNumbersChanged));

    private static void OnRowNumbersChanged(DependencyObject source, DependencyPropertyChangedEventArgs args)
    {
        DataGrid grid = source as DataGrid;
        if (grid == null)
            return;
        if ((bool)args.NewValue)
        {
            grid.LoadingRow += onGridLoadingRow;
            grid.UnloadingRow += onGridUnloadingRow;
        }
        else
        {
            grid.LoadingRow -= onGridLoadingRow;
            grid.UnloadingRow -= onGridUnloadingRow;
        }
    }

    private static void refreshDataGridRowNumbers(object sender)
    {
        DataGrid grid = sender as DataGrid;
        if (grid == null)
            return;

        foreach (var item in grid.Items)
        {
            var row = (DataGridRow)grid.ItemContainerGenerator.ContainerFromItem(item);
            if (row != null)
                row.Header = row.GetIndex() + 1;
        }
    }

    private static void onGridUnloadingRow(object sender, DataGridRowEventArgs e)
    {
        refreshDataGridRowNumbers(sender);
    }

    private static void onGridLoadingRow(object sender, DataGridRowEventArgs e)
    {
        refreshDataGridRowNumbers(sender);
    }

    [AttachedPropertyBrowsableForType(typeof(DataGrid))]
    public static void SetRowNumbers(DependencyObject element, bool value)
    {
        element.SetValue(RowNumbersProperty, value);
    }

    public static bool GetRowNumbers(DependencyObject element)
    {
        return (bool) element.GetValue(RowNumbersProperty);
    }

    #endregion
}

Answer 4

@Fredrik Hedblad 的答案对我有用。谢谢！

我添加了另一个属性来获取“偏移”值，以便 DataGrid 可以从 0 或 1（或任何设置的值）开始。

要使用该行为，（注意“b”是命名空间）

<DataGrid ItemsSource="{Binding ...}"
      b:DataGridBehavior.DisplayRowNumberOffset="1"
      b:DataGridBehavior.DisplayRowNumber="True">

修改后的类：

/// <summary>
/// Collection of DataGrid behavior
/// </summary>
public static class DataGridBehavior
{
    #region DisplayRowNumberOffset

    /// <summary>
    /// Sets the starting value of the row header if enabled
    /// </summary>
    public static DependencyProperty DisplayRowNumberOffsetProperty =
        DependencyProperty.RegisterAttached("DisplayRowNumberOffset",
                                            typeof(int),
                                            typeof(DataGridBehavior),
                                            new FrameworkPropertyMetadata(0, OnDisplayRowNumberOffsetChanged));

    public static int GetDisplayRowNumberOffset(DependencyObject target)
    {
        return (int)target.GetValue(DisplayRowNumberOffsetProperty);
    }

    public static void SetDisplayRowNumberOffset(DependencyObject target, int value)
    {
        target.SetValue(DisplayRowNumberOffsetProperty, value);
    }

    private static void OnDisplayRowNumberOffsetChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
    {
        DataGrid dataGrid = target as DataGrid;
        int offset = (int)e.NewValue;

        if (GetDisplayRowNumber(target))
        {
            WPFUtil.GetVisualChildCollection<DataGridRow>(dataGrid).
                    ForEach(d => d.Header = d.GetIndex() + offset);
        }
    }

    #endregion

    #region DisplayRowNumber

    /// <summary>
    /// Enable display of row header automatically
    /// </summary>
    /// <remarks>
    /// Source: 
    /// </remarks>
    public static DependencyProperty DisplayRowNumberProperty =
        DependencyProperty.RegisterAttached("DisplayRowNumber",
                                            typeof(bool),
                                            typeof(DataGridBehavior),
                                            new FrameworkPropertyMetadata(false, OnDisplayRowNumberChanged));

    public static bool GetDisplayRowNumber(DependencyObject target)
    {
        return (bool)target.GetValue(DisplayRowNumberProperty);
    }

    public static void SetDisplayRowNumber(DependencyObject target, bool value)
    {
        target.SetValue(DisplayRowNumberProperty, value);
    }

    private static void OnDisplayRowNumberChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
    {
        DataGrid dataGrid = target as DataGrid;
        if ((bool)e.NewValue == true)
        {
            int offset = GetDisplayRowNumberOffset(target);

            EventHandler<DataGridRowEventArgs> loadedRowHandler = null;
            loadedRowHandler = (object sender, DataGridRowEventArgs ea) =>
            {
                if (GetDisplayRowNumber(dataGrid) == false)
                {
                    dataGrid.LoadingRow -= loadedRowHandler;
                    return;
                }
                ea.Row.Header = ea.Row.GetIndex() + offset;
            };
            dataGrid.LoadingRow += loadedRowHandler;

            ItemsChangedEventHandler itemsChangedHandler = null;
            itemsChangedHandler = (object sender, ItemsChangedEventArgs ea) =>
            {
                if (GetDisplayRowNumber(dataGrid) == false)
                {
                    dataGrid.ItemContainerGenerator.ItemsChanged -= itemsChangedHandler;
                    return;
                }
                WPFUtil.GetVisualChildCollection<DataGridRow>(dataGrid).
                    ForEach(d => d.Header = d.GetIndex() + offset);
            };
            dataGrid.ItemContainerGenerator.ItemsChanged += itemsChangedHandler;
        }
    }

    #endregion // DisplayRowNumber
}

Answer 5

LoadingRowEvent 是这样触发的：

ICollectionView view = CollectionViewSource.GetDefaultView(_dataGrid.ItemsSource);
view.Refresh();

Answer 6

另一个解决方案与上面的 IValueConverter 答案有些相似，但限制很少，但具有巨大的优势。

1. ItemsSource 必须绑定到实现 IList 的集合，因为需要 IndexOf 方法来查找项目的索引。 ObservableCollection 在这里很好。
2. 集合项与 IndexOf 的比较方法不同。

该解决方案的优点是独立于DataGrid 的虚拟化类型。特别是默认虚拟化设置有效。因此它可以在相当大的虚拟化网格中正常工作。

首先，我们需要一个多值转换器：

public class RowIndexConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        if (values.Length == 2 && values[1] is IList items)
        {
            int index = items.IndexOf(values[0]);
            if (index >= 0)
            {
                return $"{index + 1}";
            }
        }
        return string.Empty;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotSupportedException();
    }
}

然后在 XAML 资源中注册它：

<Window.Resources>
    <local:RowIndexConverter x:Key="RowIndexConverter"/>
</Window.Resources>

然后在 DataGrid 的行标题模板中使用该转换器：

<DataGrid.RowHeaderTemplate>
    <ItemContainerTemplate>
        <TextBlock>
            <TextBlock.Text>
                <MultiBinding Converter="{StaticResource RowIndexConverter}">
                    <Binding Path="DataContext" RelativeSource="{RelativeSource AncestorType=DataGridRow}"/>
                    <Binding Path="ItemsSource" RelativeSource="{RelativeSource AncestorType=DataGrid}"/>
                </MultiBinding>
            </TextBlock.Text>
        </TextBlock>
    </ItemContainerTemplate>
</DataGrid.RowHeaderTemplate>

就是这样。