Question

关于如何在.Net 4 DataGrid中实现以下内容的任何想法：

private void grid_KeyDown(object sender, KeyEventArgs e)
{
    if (e.Key == Key.Delete)
    {
        DataGridCell cell = e.OriginalSource as DataGridCell;

        if (cell == null) { return; }

        if (!cell.IsReadOnly && cell.IsEnabled)
        {
            // Set the cell content (and the property of the object binded to it)
            // to null
        }
    }
}

此行为适用于任何单元格，因此我不想对列或属性名称进行硬编码。

编辑：解决方案我想出了：

if (e.Key == Key.Delete)
{
    DataGridCell cell = e.OriginalSource as DataGridCell;

     if (cell == null) { return; }

     if (!cell.IsReadOnly && cell.IsEnabled)
     {
          TextBlock tb = cell.Content as TextBlock;

          if (tb != null)
          {
               Binding binding = BindingOperations.GetBinding(tb, TextBlock.TextProperty);

               if (binding == null) { return; }

               BindingExpression exp = BindingOperations.GetBindingExpression(tb, TextBlock.TextProperty);

               PropertyInfo info = exp.DataItem.GetType().GetProperty(binding.Path.Path);

               if (info == null) { return; }

               info.SetValue(exp.DataItem, null, null);
          }
    }
}

Answer 1

我需要做几件事才能让它发挥作用：

在编辑时过滤掉删除键按下（找不到明显的方法来检测是否在编辑模式下）：

private bool _isEditing = false;
private void datagrid_BeginningEdit(object sender, DataGridBeginningEditEventArgs e)
{   _isEditing = true; }

private void datagrid_CellEditEnding(object sender, DataGridCellEditEndingEventArgs e)
{   _isEditing = false; }

处理KeyUp消息（Keygown消息由datagrid处理）：

private void dataGrid_KeyUp(object sender, KeyEventArgs e)
{
    if (!_isEditing && e.Key == Key.Delete && Keyboard.Modifiers == ModifierKeys.None)
    {
        foreach (var cellInfo in dataGrid.SelectedCells)
        {
           var column = cellInfo.Column as DataGridBoundColumn;
           if (column != null)
           {
              var binding = column.Binding as Binding;
              if (binding != null)
                  BindingHelper.SetSource(cellInfo.Item, binding, null);
           }
        }
    }
}

使用框架帮助程序类将value = null路由到基础视图模型

public class BindingHelper: FrameworkElement
{
   public static void SetSource(object source, Binding binding, object value)
   {
       var fe = new BindingHelper();
       var newBinding = new Binding(binding.Path.Path)
       {
           Mode = BindingMode.OneWayToSource,
           Source = source,
       };
       fe.SetBinding(ValueProperty, newBinding);
       fe.Value = value;
    }

    #region Value Dependency Property
    public object Value
    {
        get { return (object)GetValue(ValueProperty); }
        set { SetValue(ValueProperty, value); }
    }

    public static readonly DependencyProperty ValueProperty =
       DependencyProperty.Register("Value", typeof(object), typeof(BindingHelper));
    #endregion
}

Answer 2

这可能相当复杂，取决于单元格的模板等。

我想你必须使用各种BindingOperations方法（BindingOperations.GetBinding，BindingOperations.GetBindingExpression等）来破坏绑定值？

按下Delete键时删除WPF DataGrid中的单元格内容

2 个答案: