在分页

Question

我正在使用Telerik的RadgridView和RadDataPager进行分页。附加行为以获取网格的所有选定记录。但是在分页时不保留选定的记录（移动到下一页时清除选定的记录）。

要解决此问题，请处理radgridview.Items.PageIndexChanging事件以检查分页是否已完成。订阅此事件会影响gridview的标题行选择。选中标题行复选框（选择所有选项）将选择所有网格行，但不选择标题行。第二次复选框选择选择标题行。

如何解决此问题？

   <telerik:RadGridView Grid.Row="1"
                                  Grid.Column="0"
                                  GroupRenderMode="Flat"
                                  ColumnWidth="*"
                                  Margin="5"
                                  x:Name="radGridViewSupportingDocument"
                                  IsSynchronizedWithCurrentItem="False"
                                  ItemsSource="{Binding PagedSource, ElementName=radDataPagerSupportingDocument}"
                                  common:CustomFilterBehavior.TextBox="{Binding ElementName=radAutoCompleteBoxSearch}"
                                  Style="{StaticResource radGridViewStyle}"
                                  SelectionMode="Extended"
                                  IsReadOnly="True"
                                  >



 <telerik:RadDataPager PageSize="30"
                                   x:Name="radDataPagerSupportingDocument"
                                   Margin="5"
                                   Source="{Binding Documents}"
                                   IsTotalItemCountFixed="True"
                                   DisplayMode="FirstLastPreviousNextNumeric, Text"
                                   Grid.ColumnSpan="2"
                                   Grid.Row="2"
                                   Grid.Column="2"
                                   />




 public class MultiSelectBehavior : Behavior<RadGridView>
    {
        bool _collectionChangedSuspended = false;

        private bool _isPageIndexChanged;
        private ICollection removedItems = null;
        protected override void OnAttached()
        {

            AssociatedObject.SelectedItems.CollectionChanged += GridSelectedItems_CollectionChanged;
            AssociatedObject.SelectionChanging += AssociatedObject_SelectionChanging;
            AssociatedObject.SelectionChanged += AssociatedObject_SelectionChanged;
            AssociatedObject.Items.PageChanging += Items_PageChanging;
            AssociatedObject.Loaded += AssociatedObject_Loaded;
            base.OnAttached();
        }

        void AssociatedObject_Loaded(object sender, RoutedEventArgs e)
        {
            (sender as RadGridView).Focus();
        }

        void AssociatedObject_SelectionChanged(object sender, SelectionChangeEventArgs e)
        {
            if (_isPageIndexChanged)
            {
                foreach (var item in removedItems)
                {
                    if (!AssociatedObject.Items.Contains(item))
                    {
                        AssociatedObject.SelectedItems.Add(item);
                    }
                }
                removedItems = null;
                _isPageIndexChanged = false;
            }
        }

        void AssociatedObject_SelectionChanging(object sender, SelectionChangingEventArgs e)
        {
            if (_isPageIndexChanged)
            {
                removedItems = e.RemovedItems;
            }
        }

        void Items_PageChanging(object sender, Telerik.Windows.Data.PageChangingEventArgs e)
        {
            _isPageIndexChanged = true;
        }

        protected override void OnDetaching()
        {
            AssociatedObject.SelectedItems.CollectionChanged -= GridSelectedItems_CollectionChanged;
            AssociatedObject.SelectionChanging -= AssociatedObject_SelectionChanging;
            AssociatedObject.Items.PageChanging -= Items_PageChanging;
            AssociatedObject.SelectionChanged -= AssociatedObject_SelectionChanged;
            base.OnDetaching();
        }


         /// <summary>
        /// Getter/Setter for DependencyProperty, bound to the DataContext's SelectedItems ObservableCollection
        /// </summary>
        public INotifyCollectionChanged SelectedItems
        {
            get { return (INotifyCollectionChanged)GetValue(SelectedItemsProperty); }
            set { SetValue(SelectedItemsProperty, value); }
        }

        /// <summary>
        /// Dependency Property "SelectedItems" is target of binding to DataContext's SelectedItems
        /// </summary>
        public static readonly DependencyProperty SelectedItemsProperty =
            DependencyProperty.Register("SelectedItems", typeof(INotifyCollectionChanged), typeof(MultiSelectBehavior), new PropertyMetadata(OnSelectedItemsPropertyChanged));

        /// <summary>
        /// PropertyChanged handler for DependencyProperty "SelectedItems"
        /// </summary>
        private static void OnSelectedItemsPropertyChanged(DependencyObject target, DependencyPropertyChangedEventArgs args)
        {
            INotifyCollectionChanged collection = args.NewValue as INotifyCollectionChanged;
            if (collection != null)
            {
                // Hook to the Network's SelectedItems
                collection.CollectionChanged += (target as MultiSelectBehavior).ContextSelectedItems_CollectionChanged;
            }
        }

        /// <summary>
        /// Will be called, when the Network's SelectedItems collection changes
        /// </summary>
        void ContextSelectedItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
        {
            if (_collectionChangedSuspended) return;    // Don't react recursively to CollectionChanged events

            _collectionChangedSuspended = true;

            // Select and unselect items in the grid
            if (e.NewItems != null)
                foreach (object item in e.NewItems)
                    AssociatedObject.SelectedItems.Add(item);

            if (e.OldItems != null)
                foreach (object item in e.OldItems)
                    AssociatedObject.SelectedItems.Remove(item);

            _collectionChangedSuspended = false;
        }

        /// <summary>
        /// Will be called when the GridView's SelectedItems collection changes
        /// </summary>
        void GridSelectedItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
        {
            if (_collectionChangedSuspended) return;    // Don't react recursively to CollectionChanged events

            _collectionChangedSuspended = true;

            // Select and unselect items in the DataContext
            if (e.NewItems != null)
                foreach (object item in e.NewItems)
                    (SelectedItems as IList).Add(item);

            if (e.OldItems != null)
                foreach (object item in e.OldItems)
                    (SelectedItems as IList).Remove(item);

            _collectionChangedSuspended = false;
        }
    }