private static void RollbackOnLostFocus(object sender, KeyboardFocusChangedEventArgs e)
{
if (!(sender is ItemsControl senderItemsControl))
{
return;
}
if (!(Keyboard.FocusedElement is UIElement focusedElement))
{
return;
}
ItemsControl focusedDatagrid = ControlsHelper.FindParentWithItemPresenter <ItemsControl>(focusedElement); //let's see if the new focused element is inside a datagrid
if (focusedDatagrid == senderItemsControl)
{
return;
//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
}
//otherwise, the focus went outside the datagrid; in order to avoid exceptions like ("DeferRefresh' is not allowed during an AddNew or EditItem transaction")
//or ("CommitNew is not allowed for this view"), we undo the possible pending changes, if any
IEditableCollectionView collection = senderItemsControl.Items as IEditableCollectionView;
if (collection.CanCancelEdit)
{
if (collection.IsEditingItem)
{
collection.CancelEdit();
}
else if (collection.IsAddingNew)
{
collection.CancelNew();
}
}
}