[英]WPF DataGrid SelectedItem binding stops working after item change
My problem/situation is very similar to Wpf DataGrid SelectedItem loses binding after cell edit but I'm not using any "custom" WPF framework. 我的问题/情况非常类似于Wpf DataGrid SelectedItem在单元格编辑后失去绑定但我没有使用任何“自定义”WPF框架。 I have a model that implements INotifyPropertyChanged
and IEditableObject
, and a grid bound to an ObservableCollection<T>
. 我有一个实现INotifyPropertyChanged
和IEditableObject
的模型,以及一个绑定到ObservableCollection<T>
的网格。 The grid's SelectedItem
property is bound to a property on the VM. 网格的SelectedItem
属性绑定到VM上的属性。
With a break point, I can see my ViewModel.SelectedItem
property change as I select different rows in the grid. 有了断点,我可以看到我的ViewModel.SelectedItem
属性发生变化,因为我选择了网格中的不同行。 The moment I change a value on a row, however, the ViewModel.SelectedItem
property is no longer set as I change focus on the rows. 但是,当我更改行上的值时,不再设置ViewModel.SelectedItem
属性,因为我将更改焦点放在行上。 The solution identified in the above link does not work since I'm not using a custom WPF framework, just naked WPF. 上面链接中标识的解决方案不起作用,因为我没有使用自定义WPF框架,只是裸WPF。
Any ideas? 有任何想法吗?
// View model area
public IPurchaseorderItem SelectedItem
{
get
{
return _selectedItem;
}
set
{
if (_selectedItem != value)
{
_selectedItem = value;
SelectItemCommand.NotifyCanExecuteChanged();
RemoveItemCommand.NotifyCanExecuteChanged();
}
}
}
// XAML SelectedItem binding
<views:NoBindingGroupDataGrid SelectedItem="{Binding SelectedItem, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
// Special Grid to clear binding groups (read on a similarly themed SO question/answer)
internal sealed class NoBindingGroupDataGrid : DataGrid
{
private bool _editing = false;
protected override System.Windows.Size MeasureOverride(System.Windows.Size availableSize)
{
var desiredSize = base.MeasureOverride(availableSize);
ClearBindingGroup();
return desiredSize;
}
protected override void OnCellEditEnding(DataGridCellEditEndingEventArgs e)
{
base.OnCellEditEnding(e);
if (!_editing)
{
_editing = true;
CommitEdit(DataGridEditingUnit.Row, true);
_editing = false;
}
}
private void ClearBindingGroup()
{
ItemBindingGroup = null;
foreach (var item in Items)
{
var row = ItemContainerGenerator.ContainerFromItem(item) as FrameworkElement;
if (row != null)
{
row.BindingGroup = null;
}
}
}
}
Apparently the SelectedItem dependency property on DataGrid is broken and not being used correctly. 显然,DataGrid上的SelectedItem依赖项属性已损坏且未正确使用。 After some debugging using OnPropertyChanged, I found that the grid is actually setting a "CurrentItem" property reliably. 在使用OnPropertyChanged进行一些调试之后,我发现网格实际上是可靠地设置了“CurrentItem”属性。 I changed to use CurrentItem instead and everything appears to work correctly... the user's "selected row" is being sent to the VM without incident. 我改为使用CurrentItem,一切似乎都正常工作......用户的“选定行”正在被发送到VM而没有发生任何事故。
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