在wpf中，我设置了一个标签控件，它绑定到一个对象集合，每个对象都有一个数据模板，数据网格显示数据。如果我选择一个特定的单元格并将其置于编辑模式，通过转到另一个选项卡离开网格，这将导致返回数据网格时抛出以下异常：
在AddNew或EditItem事务期间，不允许使用“DeferRefresh”。看来该单元格从未离开编辑模式。是否有一种简单的方法可以将单元格从编辑模式中取出，或者是否还有其他功能？
更新：看起来如果我没有将标签控件绑定到数据源，而是显式定义每个标签，然后将数据源中的每个项目绑定到内容控件，此问题就出现了远。这不是一个很好的解决方案，所以我仍然想知道如何将集合直接绑定到选项卡控件。
更新：所以我实际为自己的解决方案所做的就是使用ListView和内容控件来代替选项卡控件。我使用样式使列表视图看起来像。视图模型公开一组子视图模型，并允许用户通过列表视图选择一个。然后，内容控件呈现所选择的视图模型，并且每个视图模型具有包含数据网格的关联数据模板。使用此设置在视图模型之间切换，而在网格上的编辑模式下，将正确结束编辑模式并保存数据。
以下是用于设置的xaml：
<ListView ItemTemplate="{StaticResource MakeItemsLookLikeTabs}"
ItemsSource="{Binding ViewModels}"
SelectedItem="{Binding Selected}"
Style="{StaticResource MakeItLookLikeATabControl}"/>
<ContentControl Content="{Binding Selected}">
我会接受Phil的答案，因为这也应该有效，但对我来说，上面的解决方案似乎在项目之间更容易移植。
答案 0 :(得分：10)
我基于this线程中找到的代码实现了DataGrid的行为。
用法：<DataGrid local:DataGridCommitEditBehavior.CommitOnLostFocus="True" />
代码：
using System.Collections.Generic;
using System.Reflection;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Input;
using System.Windows.Media;
/// <summary>
/// Provides an ugly hack to prevent a bug in the data grid.
/// https://connect.microsoft.com/VisualStudio/feedback/details/532494/wpf-datagrid-and-tabcontrol-deferrefresh-exception
/// </summary>
public class DataGridCommitEditBehavior
{
public static readonly DependencyProperty CommitOnLostFocusProperty =
DependencyProperty.RegisterAttached(
"CommitOnLostFocus",
typeof(bool),
typeof(DataGridCommitEditBehavior),
new UIPropertyMetadata(false, OnCommitOnLostFocusChanged));
/// <summary>
/// A hack to find the data grid in the event handler of the tab control.
/// </summary>
private static readonly Dictionary<TabPanel, DataGrid> ControlMap = new Dictionary<TabPanel, DataGrid>();
public static bool GetCommitOnLostFocus(DataGrid datagrid)
{
return (bool)datagrid.GetValue(CommitOnLostFocusProperty);
}
public static void SetCommitOnLostFocus(DataGrid datagrid, bool value)
{
datagrid.SetValue(CommitOnLostFocusProperty, value);
}
private static void CommitEdit(DataGrid dataGrid)
{
dataGrid.CommitEdit(DataGridEditingUnit.Cell, true);
dataGrid.CommitEdit(DataGridEditingUnit.Row, true);
}
private static DataGrid GetParentDatagrid(UIElement element)
{
UIElement childElement; // element from which to start the tree navigation, looking for a Datagrid parent
if (element is ComboBoxItem)
{
// Since ComboBoxItem.Parent is null, we must pass through ItemsPresenter in order to get the parent ComboBox
var parentItemsPresenter = VisualTreeFinder.FindParentControl<ItemsPresenter>(element as ComboBoxItem);
var combobox = parentItemsPresenter.TemplatedParent as ComboBox;
childElement = combobox;
}
else
{
childElement = element;
}
var parentDatagrid = VisualTreeFinder.FindParentControl<DataGrid>(childElement);
return parentDatagrid;
}
private static TabPanel GetTabPanel(TabControl tabControl)
{
return
(TabPanel)
tabControl.GetType().InvokeMember(
"ItemsHost",
BindingFlags.NonPublic | BindingFlags.GetProperty | BindingFlags.Instance,
null,
tabControl,
null);
}
private static void OnCommitOnLostFocusChanged(DependencyObject depObj, DependencyPropertyChangedEventArgs e)
{
var dataGrid = depObj as DataGrid;
if (dataGrid == null)
{
return;
}
if (e.NewValue is bool == false)
{
return;
}
var parentTabControl = VisualTreeFinder.FindParentControl<TabControl>(dataGrid);
var tabPanel = GetTabPanel(parentTabControl);
if (tabPanel != null)
{
ControlMap[tabPanel] = dataGrid;
}
if ((bool)e.NewValue)
{
// Attach event handlers
if (parentTabControl != null)
{
tabPanel.PreviewMouseLeftButtonDown += OnParentTabControlPreviewMouseLeftButtonDown;
}
dataGrid.LostKeyboardFocus += OnDataGridLostFocus;
dataGrid.DataContextChanged += OnDataGridDataContextChanged;
dataGrid.IsVisibleChanged += OnDataGridIsVisibleChanged;
}
else
{
// Detach event handlers
if (parentTabControl != null)
{
tabPanel.PreviewMouseLeftButtonDown -= OnParentTabControlPreviewMouseLeftButtonDown;
}
dataGrid.LostKeyboardFocus -= OnDataGridLostFocus;
dataGrid.DataContextChanged -= OnDataGridDataContextChanged;
dataGrid.IsVisibleChanged -= OnDataGridIsVisibleChanged;
}
}
private static void OnDataGridDataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
{
var dataGrid = (DataGrid)sender;
CommitEdit(dataGrid);
}
private static void OnDataGridIsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
var senderDatagrid = (DataGrid)sender;
if ((bool)e.NewValue == false)
{
CommitEdit(senderDatagrid);
}
}
private static void OnDataGridLostFocus(object sender, KeyboardFocusChangedEventArgs e)
{
var dataGrid = (DataGrid)sender;
var focusedElement = Keyboard.FocusedElement as UIElement;
if (focusedElement == null)
{
return;
}
var focusedDatagrid = GetParentDatagrid(focusedElement);
// Let's see if the new focused element is inside a datagrid
if (focusedDatagrid == dataGrid)
{
// If the new focused element is inside the same datagrid, then we don't need to do anything;
// this happens, for instance, when we enter in edit-mode: the DataGrid element loses keyboard-focus,
// which passes to the selected DataGridCell child
return;
}
CommitEdit(dataGrid);
}
private static void OnParentTabControlPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
var dataGrid = ControlMap[(TabPanel)sender];
CommitEdit(dataGrid);
}
}
public static class VisualTreeFinder
{
/// <summary>
/// Find a specific parent object type in the visual tree
/// </summary>
public static T FindParentControl<T>(DependencyObject outerDepObj) where T : DependencyObject
{
var dObj = VisualTreeHelper.GetParent(outerDepObj);
if (dObj == null)
{
return null;
}
if (dObj is T)
{
return dObj as T;
}
while ((dObj = VisualTreeHelper.GetParent(dObj)) != null)
{
if (dObj is T)
{
return dObj as T;
}
}
return null;
}
}
答案 1 :(得分：7)
通过检测用户何时点击TabItem然后对DataGrid中的可见TabControl进行修改，我设法解决了这个问题。我假设当用户点击回来时，用户会希望他们的更改仍然存在。
代码段：
// PreviewMouseDown event handler on the TabControl
private void TabControl_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
if (IsUnderTabHeader(e.OriginalSource as DependencyObject))
CommitTables(yourTabControl);
}
private bool IsUnderTabHeader(DependencyObject control)
{
if (control is TabItem)
return true;
DependencyObject parent = VisualTreeHelper.GetParent(control);
if (parent == null)
return false;
return IsUnderTabHeader(parent);
}
private void CommitTables(DependencyObject control)
{
if (control is DataGrid)
{
DataGrid grid = control as DataGrid;
grid.CommitEdit(DataGridEditingUnit.Row, true);
return;
}
int childrenCount = VisualTreeHelper.GetChildrenCount(control);
for (int childIndex = 0; childIndex < childrenCount; childIndex++)
CommitTables(VisualTreeHelper.GetChild(control, childIndex));
}
这是在背后的代码中。
答案 2 :(得分：0)
我认为你应该做的与@myermian所说的非常接近。 有一个名为CellEditEnding的事件结束此事件将允许您拦截并决定删除不需要的行。
private void dataGrid1_CellEditEnding(object sender, DataGridCellEditEndingEventArgs e)
{
DataGrid grid = (DataGrid)sender;
TextBox cell = (TextBox)e.EditingElement;
if(String.IsNullOrEmpty(cell.Text) && e.EditAction == DataGridEditAction.Commit)
{
grid.CancelEdit(DataGridEditingUnit.Row);
e.Cancel = true;
}
}
答案 3 :(得分：0)
我同意Phil Gan的回答，解决这个问题的方法应该是检测用户何时点击TabItem，然后在TabControl中对可见的DataGrid进行编辑。
您可以看到此链接的相似性问题...
Gridview not visible even after binding….
希望它可以帮助......
答案 4 :(得分：0)
此错误在.NET Framework 4.5中得到解决。您可以在this link下载。