WPF Datagrid 的“按下删除键”事件是什么？

Question

我想让用户突出显示 WPF DataGrid 上的一行并按删除键删除该行。

• 该功能已经内置在网格的 UI 中，因此对于用户而言，该行消失了
• 我目前在 SelectionChanged 事件上处理这个问题（代码如下）
• 我遍历所有“e.RemovedItems”并使用 LINQ 删除它们

问题是：即使您只是选择一行并移开它，选择更改也会被触发并且该行位于 e.RemovedItems 中（这很奇怪，为什么要简单地选择一些东西把它放在 RemovedItems 容器中？）。

所以我正在寻找一个 DeleteKeyPressed 事件，以便我可以简单地处理它。那个事件叫什么？

我正在使用 2009 年 3 月的工具包。

XAML：

<Grid DockPanel.Dock="Bottom">
    <toolkit:DataGrid x:Name="TheDataGrid" 
                      SelectionChanged="TheDataGrid_SelectionChanged"
                      AutoGenerateColumns="True"
                      RowEditEnding="TheDataGrid_RowEditEnding"/>

代码隐藏：

private void TheDataGrid_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)
{
    if (e.RemovedItems.Count > 0)
    {
        Message.Text = "The following were removed: ";
        foreach (object obj in e.RemovedItems)
        {
            Customer customer = obj as Customer;
            Message.Text += customer.ContactName + ",";
            _db.Order_Details.DeleteAllOnSubmit(
                customer.Orders.SelectMany(o => o.Order_Details));
            _db.Orders.DeleteAllOnSubmit(customer.Orders);
            _db.Customers.DeleteOnSubmit(customer);
        } 
    }

    try
    {
        _db.SubmitChanges();
    }
    catch (Exception ex)
    {
        Message.Text = ex.Message;
    }
}

---

回答：

感谢 lnferis，这正是我要找的，这是我为数据网格完成的删除处理事件，请注意 KeyDown 事件由于某种原因不会触发。

XAML：

<toolkit:DataGrid x:Name="TheDataGrid" 
                  KeyDown="TheDataGrid_KeyDown"
                  PreviewKeyDown="TheDataGrid_PreviewKeyDown"
                  AutoGenerateColumns="True"
                  RowEditEnding="TheDataGrid_RowEditEnding"/>

代码隐藏

private void TheDataGrid_PreviewKeyDown(object sender, KeyEventArgs e)
{
    if (e.Key == Key.Delete)
    {
        var grid = (DataGrid)sender;

        if (grid.SelectedItems.Count > 0)
        {
            string checkMessage = "The following will be removed: ";

            foreach (var row in grid.SelectedItems)
            {
                Customer customer = row as Customer;
                checkMessage += customer.ContactName + ",";
            }
            checkMessage = Regex.Replace(checkMessage, ",$", "");

            var result = MessageBox.Show(checkMessage, "Delete", MessageBoxButton.OKCancel);
            if (result == MessageBoxResult.OK)
            {
                foreach (var row in grid.SelectedItems)
                {
                    Customer customer = row as Customer;
                    _db.Order_Details.DeleteAllOnSubmit(
                        customer.Orders.SelectMany(o => o.Order_Details));
                    _db.Orders.DeleteAllOnSubmit(customer.Orders);
                    _db.Customers.DeleteOnSubmit(customer);
                }
                _db.SubmitChanges();
            }
            else
            {
                foreach (var row in grid.SelectedItems)
                {
                    Customer customer = row as Customer;
                    LoadData();
                    _db.Refresh(System.Data.Linq.RefreshMode.OverwriteCurrentValues, customer); //TODO: this doesn't refresh the datagrid like the other instance in this code
                }
            }
        }
    }
}

private void TheDataGrid_KeyDown(object sender, KeyEventArgs e)
{
    Console.WriteLine("never gets here for some reason");
}

Answer 1

您要处理 KeyUp 或 KeyDown 事件并检查按下的键是否删除。

private void OnKeyDown(object sender, KeyEventArgs e) {
  if ( Key.Delete == e.Key ) {
    // Delete pressed
  }
}

Answer 2

RemovedItems 项目反映了从选择中删除的项目，而不是从网格中删除的项目。

处理PreviewKeyDown 事件，并使用SelectedItems 属性删除那里的选定行：

private void PreviewKeyDownHandler(object sender, KeyEventArgs e) {
    var grid = (DataGrid)sender;
    if ( Key.Delete == e.Key ) {
        foreach (var row in grid.SelectedItems) {
            ... // perform linq stuff to delete here
        }
    }
}

Answer 3

您要将 DataGrid 绑定到什么？ 理想情况下，您应该对要绑定的集合上的 CollectionChanged 事件做出反应。这样，您的逻辑（删除已删除项目）将与您的 UI 分离。

如果原始集合没有必要的事件，您可以构建一个包含对象的 Observable 集合并将其绑定到 ItemsSource。

它可能不适合您的特定设置，但我通常是这样做的。

Answer 4

请按照下面的代码。下面的代码我已经成功了。

如果需要更改，请告诉我。

 private void grdEmployee_PreviewKeyDown(object sender, KeyEventArgs e)
    {

        if (e.Device.Target.GetType().Name == "DataGridCell")
        {
            if (e.Key == Key.Delete)
            {
                MessageBoxResult res = MessageBox.Show("Are you sure want to delete?", "Confirmation!", MessageBoxButton.YesNo,MessageBoxImage.Question);
                e.Handled = (res == MessageBoxResult.No);
            }
        }
    }

Answer 5

XAML

<DataGrid ItemsSource="{Binding}" CommandManager.PreviewCanExecute="Grid_PreviewCanExecute" />

后面的代码

private void Grid_PreviewCanExecute(object sender, CanExecuteRoutedEventArgs e)
{
  DataGrid grid = (DataGrid)sender;
  if (e.Command == DataGrid.DeleteCommand)
  {
    if (MessageBox.Show(String.Format("Would you like to delete {0}", (grid.SelectedItem as Person).FirstName), "Confirm Delete", MessageBoxButton.OKCancel) != MessageBoxResult.OK)
      e.Handled = true;
  }
}

Answer 6

聚会有点晚了，但为了让 Inferis 的回答起作用：

Dim isEditing = False
AddHandler dg.BeginningEdit, Sub() isEditing = True
AddHandler dg.RowEditEnding, Sub() isEditing = False
AddHandler dg.PreviewKeyDown, Sub(obj, ev) 
  If e.Key = Key.Delete AndAlso Not isEditing Then ...

这修复了 epalms 注释：“如果您正在编辑单元格并使用删除键删除单元格中的某些字符，您最终会删除整行”

Answer 7

最干净的解决方案是使用 PreviewCanExecute，就像 flux 回答的那样，这是一个完整的解决方案，可以让任何像我一样忽略他的答案的人更清楚：

private void Grid_PreviewCanExecute(object sender, CanExecuteRoutedEventArgs e)
{
    if (e.Command == DataGrid.DeleteCommand)
    {
        if (MessageBox.Show($"Delete something from something else?", "Confirm removal of something", MessageBoxButton.YesNo) == MessageBoxResult.Yes)
        {
            // Do what ever needs to be done when someone deletes the row
        }
        else
        {
            e.Handled = true;   
            // Handled means.. no worries, I took care of it.. and it will not delete the row
        }
    }
}

此后无需连接到 CommandManager.Executed。