/// <summary>
/// Updates contents of the ItemsSource when FeatureDataGrid's associated graphic collection changes.
/// </summary>
/// <param name="sender">Observable collection of Graphic.</param>
/// <param name="e">Collection changed event arguments.</param>
private void UpdateItemsSource(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
IList newItems = e.NewItems;
IList oldItems = e.OldItems;
if (ItemsSource == null)
{
SetItemsSource(sender as ObservableCollection <Graphic>);
}
else
{
if ((ItemsSource as PagedCollectionView) != null)
{
object currentItem = (ItemsSource as PagedCollectionView).CurrentItem;
if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Reset)
{
var features = (from object a in ItemsSource select DataSourceCreator.GetGraphicSibling(a));
newItems = (sender as ObservableCollection <Graphic>).Except(features).ToList();
oldItems = features.Except(sender as ObservableCollection <Graphic>).ToList();
}
if (newItems != null && newItems.Count > 0) // New item(s) added
{
bool shouldResetItemsSource = false;
IEnumerator enumItemsSource = ItemsSource.GetEnumerator();
if (enumItemsSource != null)
{
if (enumItemsSource.MoveNext())
{
if (!AllAttributesMatch(enumItemsSource.Current.GetType().GetProperties(), (newItems[0] as Graphic).Attributes))
{
shouldResetItemsSource = true;
}
}
else
{
shouldResetItemsSource = true;
}
}
if (shouldResetItemsSource)
{
UnregisterGraphicCollectionEventHandlers();
SetItemsSource(sender as ObservableCollection <Graphic>);
IEnumerator enumAddedGraphics = newItems.GetEnumerator();
while (enumAddedGraphics.MoveNext())
{
Graphic graphic = enumAddedGraphics.Current as Graphic;
if (graphic != null)
{
graphic.AttributeValueChanged += Graphic_AttributeValueChanged;
}
}
}
else
{
IEnumerator enumAddedGraphics = newItems.GetEnumerator();
List <Graphic> selected = GraphicsLayer.SelectedGraphics.ToList();
while (enumAddedGraphics.MoveNext())
{
Graphic graphic = enumAddedGraphics.Current as Graphic;
if (graphic != null)
{
if (graphic.Selected)
{
selected.Add(graphic);
}
ItemsSource.AddToDataSource(featureLayerInfo, graphic, objectType);
graphic.AttributeValueChanged += Graphic_AttributeValueChanged;
}
}
RestorePreviousSelection(selected);
}
}
if (oldItems != null && oldItems.Count > 0) // Item(s) removed
{
int selCount = SelectedItems.Count;
// In Silverlight removing a graphic from the GraphicsCollection causes to lose current
// selection in both GraphicsLayer and the FeatureDataGrid.
// Preserving selected items in the FeatureDataGrid:
List <Graphic> selItems = new List <Graphic>(selCount);
for (int i = 0; i < selCount; i++)
{
var row = SelectedItems[i];
var graphic = DataSourceCreator.GetGraphicSibling(row);
selItems.Add(graphic);
}
IEnumerator enumRemovedGraphics = oldItems.GetEnumerator();
while (enumRemovedGraphics.MoveNext())
{
Graphic graphic = enumRemovedGraphics.Current as Graphic;
int idxInItemsSource = GetRowIndexInItemsSource(graphic);
if (graphic != null && idxInItemsSource > -1)
{
if (graphic != null)
{
selItems.Remove(graphic);
}
ItemsSource.RemoveFromDataSource(idxInItemsSource, objectType);
// RemoveFromDataSource() method causes first item in the ItemsSource to be selected when there were no
// items selected in the data grid. We should avoid this selection by removing it from the selection:
if (selCount == 0 && SelectedItems.Count == 1)
{
SelectedItems.Clear();
}
graphic.AttributeValueChanged -= Graphic_AttributeValueChanged;
SelectedGraphics.Remove(graphic);
}
}
RestorePreviousSelection(selItems);
}
}
else
{
// If exiting ItemsSource is not a PagedCollectionView then it was empty before
// just populate it with everything in GraphicsLayer.
SetItemsSource((GraphicsLayer != null && GraphicsLayer.Graphics != null) ? (IList <Graphic>)GraphicsLayer.Graphics : new List <Graphic>());
}
}
ShowNumberOfRecords();
}
