internal void RemoveAllInternal(bool saveRecycleQueue)
{
// Take _itemMap offline, to protect against reentrancy (bug 1285179)
ItemBlock itemMap = _itemMap;
_itemMap = null;
try
{
// de-initialize the containers that are being removed
if (itemMap != null)
{
for (ItemBlock block = itemMap.Next; block != itemMap; block = block.Next)
{
RealizedItemBlock rib = block as RealizedItemBlock;
if (rib != null)
{
for (int offset = 0; offset < rib.ContainerCount; ++offset)
{
UnlinkContainerFromItem(rib.ContainerAt(offset), rib.ItemAt(offset));
}
}
}
}
}
finally
{
PrepareGrouping();
// re-initialize the data structure
_itemMap = new ItemBlock();
_itemMap.Prev = _itemMap.Next = _itemMap;
UnrealizedItemBlock uib = new UnrealizedItemBlock();
uib.InsertAfter(_itemMap);
uib.ItemCount = ItemsInternal.Count;
if (!saveRecycleQueue)
{
ResetRecyclableContainers();
}
SetAlternationCount();
// tell generators what happened
if (MapChanged != null)
{
MapChanged(null, -1, 0, uib, 0, 0);
}
}
}
/// <summary>
/// Remove generated elements.
/// </summary>
private void Remove(GeneratorPosition position, int count, bool isRecycling)
{
if (position.Offset != 0)
throw new ArgumentException(SR.Get(SRID.RemoveRequiresOffsetZero, position.Index, position.Offset), "position");
if (count <= 0)
throw new ArgumentException(SR.Get(SRID.RemoveRequiresPositiveCount, count), "count");
if (_itemMap == null)
{
// ignore reentrant call (during RemoveAllInternal)
Debug.Assert(false, "Unexpected reentrant call to ICG.Remove");
return;
}
int index = position.Index;
ItemBlock block;
// find the leftmost item to remove
int offsetL = index;
for (block = _itemMap.Next; block != _itemMap; block = block.Next)
{
if (offsetL < block.ContainerCount)
break;
offsetL -= block.ContainerCount;
}
RealizedItemBlock blockL = block as RealizedItemBlock;
// find the rightmost item to remove
int offsetR = offsetL + count - 1;
for (; block != _itemMap; block = block.Next)
{
if (!(block is RealizedItemBlock))
throw new InvalidOperationException(SR.Get(SRID.CannotRemoveUnrealizedItems, index, count));
if (offsetR < block.ContainerCount)
break;
offsetR -= block.ContainerCount;
}
RealizedItemBlock blockR = block as RealizedItemBlock;
// de-initialize the containers that are being removed
RealizedItemBlock rblock = blockL;
int offset = offsetL;
while (rblock != blockR || offset <= offsetR)
{
DependencyObject container = rblock.ContainerAt(offset);
UnlinkContainerFromItem(container, rblock.ItemAt(offset));
// DataGrid generates non-GroupItem for NewItemPlaceHolder
// Dont recycle in this case.
bool isNewItemPlaceHolderWhenGrouping = _generatesGroupItems && !(container is GroupItem);
if (isRecycling && !isNewItemPlaceHolderWhenGrouping)
{
Debug.Assert(!_recyclableContainers.Contains(container), "trying to add a container to the collection twice");
if (_containerType == null)
{
_containerType = container.GetType();
}
else if (_containerType != container.GetType())
{
throw new InvalidOperationException(SR.Get(SRID.CannotRecyleHeterogeneousTypes));
}
_recyclableContainers.Enqueue(container);
}
if (++offset >= rblock.ContainerCount && rblock != blockR)
{
rblock = rblock.Next as RealizedItemBlock;
offset = 0;
}
}
// see whether the range hits the edge of a block on either side,
// and whether the a`butting block is an unrealized gap
bool edgeL = (offsetL == 0);
bool edgeR = (offsetR == blockR.ItemCount-1);
bool abutL = edgeL && (blockL.Prev is UnrealizedItemBlock);
bool abutR = edgeR && (blockR.Next is UnrealizedItemBlock);
// determine the target (unrealized) block,
// the offset within the target at which to insert items,
// and the intial change in cumulative item count
UnrealizedItemBlock blockT;
ItemBlock predecessor = null;
int offsetT;
int deltaCount;
if (abutL)
{
blockT = (UnrealizedItemBlock)blockL.Prev;
offsetT = blockT.ItemCount;
deltaCount = -blockT.ItemCount;
}
else if (abutR)
{
blockT = (UnrealizedItemBlock)blockR.Next;
offsetT = 0;
deltaCount = offsetL;
}
else
{
blockT = new UnrealizedItemBlock();
offsetT = 0;
deltaCount = offsetL;
// remember where the new block goes, so we can insert it later
predecessor = (edgeL) ? blockL.Prev : blockL;
}
// move items within the range to the target block
for (block = blockL; block != blockR; block = block.Next)
{
int itemCount = block.ItemCount;
MoveItems(block, offsetL, itemCount-offsetL,
blockT, offsetT, deltaCount);
offsetT += itemCount-offsetL;
offsetL = 0;
deltaCount -= itemCount;
if (block.ItemCount == 0)
block.Remove();
}
// the last block in the range is a little special...
// Move the last unrealized piece.
int remaining = block.ItemCount - 1 - offsetR;
MoveItems(block, offsetL, offsetR - offsetL + 1,
blockT, offsetT, deltaCount);
// Move the remaining realized items
RealizedItemBlock blockX = blockR;
if (!edgeR)
{
if (blockL == blockR && !edgeL)
{
blockX = new RealizedItemBlock();
}
MoveItems(block, offsetR+1, remaining,
blockX, 0, offsetR+1);
}
// if we created any new blocks, insert them in the list
if (predecessor != null)
blockT.InsertAfter(predecessor);
if (blockX != blockR)
blockX.InsertAfter(blockT);
RemoveAndCoalesceBlocksIfNeeded(block);
}
void OnItemMoved(object item, int oldIndex, int newIndex)
{
if (_itemMap == null)
{
// reentrant call (from RemoveAllInternal) shouldn't happen,
// but if it does, don't crash
Debug.Assert(false, "unexpected reentrant call to OnItemMoved");
return;
}
DependencyObject container = null; // the corresponding container
int containerCount = 0;
UnrealizedItemBlock uib;
// search for the moved item
GeneratorPosition position;
ItemBlock block;
int offsetFromBlockStart;
int correctIndex;
GetBlockAndPosition(item, oldIndex, true, out position, out block, out offsetFromBlockStart, out correctIndex);
GeneratorPosition oldPosition = position;
RealizedItemBlock rib = block as RealizedItemBlock;
if (rib != null)
{
containerCount = 1;
container = rib.ContainerAt(offsetFromBlockStart);
}
// remove the item, and remove the block if it's now empty
MoveItems(block, offsetFromBlockStart + 1, block.ItemCount - offsetFromBlockStart - 1, block, offsetFromBlockStart, 0);
--block.ItemCount;
RemoveAndCoalesceBlocksIfNeeded(block);
//
// now insert into the new spot.
//
position = new GeneratorPosition(-1,0);
block = _itemMap.Next;
offsetFromBlockStart = newIndex;
while (block != _itemMap && offsetFromBlockStart >= block.ItemCount)
{
offsetFromBlockStart -= block.ItemCount;
if (block.ContainerCount > 0)
{
position.Index += block.ContainerCount;
position.Offset = 0;
}
else
{
position.Offset += block.ItemCount;
}
block = block.Next;
}
position.Offset += offsetFromBlockStart + 1;
// if it's an unrealized block, add the item by bumping the count
uib = block as UnrealizedItemBlock;
if (uib != null)
{
MoveItems(uib, offsetFromBlockStart, 1, uib, offsetFromBlockStart+1, 0);
++ uib.ItemCount;
}
// if the item can be added to a previous unrealized block, do so
else if ((offsetFromBlockStart == 0 || block == _itemMap) &&
((uib = block.Prev as UnrealizedItemBlock) != null))
{
++ uib.ItemCount;
}
// otherwise, create a new unrealized block
else
{
uib = new UnrealizedItemBlock();
uib.ItemCount = 1;
// split the current realized block, if necessary
if (offsetFromBlockStart > 0 && (rib = block as RealizedItemBlock) != null)
{
RealizedItemBlock newBlock = new RealizedItemBlock();
MoveItems(rib, offsetFromBlockStart, rib.ItemCount - offsetFromBlockStart, newBlock, 0, offsetFromBlockStart);
newBlock.InsertAfter(rib);
position.Index += block.ContainerCount;
position.Offset = 1;
offsetFromBlockStart = 0;
block = newBlock;
}
uib.InsertBefore(block);
}
DependencyObject parent = VisualTreeHelper.GetParentInternal(container);
// tell layout what happened
if (ItemsChanged != null)
{
ItemsChanged(this, new ItemsChangedEventArgs(NotifyCollectionChangedAction.Move, position, oldPosition, 1, containerCount));
}
// unhook the container. Do this after layout has (presumably) removed it from
// the UI, so that it doesn't inherit DataContext falsely.
if (container != null)
{
if (parent == null || VisualTreeHelper.GetParentInternal(container) != parent)
{
UnlinkContainerFromItem(container, item);
}
else
{
// If the container has the same visual parent as before then that means that
// the container was just repositioned within the parent's VisualCollection.
// we don't need to unlink the container, but we do need to re-realize the block.
Realize(uib, offsetFromBlockStart, item, container);
}
}
// fix up the AlternationIndex on containers affected by the move
if (_alternationCount > 0)
{
// start with the smaller of the two positions, and proceed forward.
// This tends to preserve the AlternatonIndex on containers at the
// front of the list, as users expect
int index = Math.Min(oldIndex, newIndex);
GetBlockAndPosition(index, out position, out block, out offsetFromBlockStart);
SetAlternationIndex(block, offsetFromBlockStart, GeneratorDirection.Forward);
}
}
// Called when an item is added to the items collection
void OnItemAdded(object item, int index)
{
if (_itemMap == null)
{
// reentrant call (from RemoveAllInternal) shouldn't happen,
// but if it does, don't crash
Debug.Assert(false, "unexpected reentrant call to OnItemAdded");
return;
}
ValidateAndCorrectIndex(item, ref index);
GeneratorPosition position = new GeneratorPosition(-1,0);
// find the block containing the new item
ItemBlock block = _itemMap.Next;
int offset = index;
while (block != _itemMap && offset >= block.ItemCount)
{
offset -= block.ItemCount;
position.Index += block.ContainerCount;
block = block.Next;
}
position.Offset = offset + 1;
// if it's an unrealized block, add the item by bumping the count
UnrealizedItemBlock uib = block as UnrealizedItemBlock;
if (uib != null)
{
MoveItems(uib, offset, 1, uib, offset+1, 0);
++ uib.ItemCount;
}
// if the item can be added to a previous unrealized block, do so
else if ((offset == 0 || block == _itemMap) &&
((uib = block.Prev as UnrealizedItemBlock) != null))
{
++ uib.ItemCount;
}
// otherwise, create a new unrealized block
else
{
uib = new UnrealizedItemBlock();
uib.ItemCount = 1;
// split the current realized block, if necessary
RealizedItemBlock rib;
if (offset > 0 && (rib = block as RealizedItemBlock) != null)
{
RealizedItemBlock newBlock = new RealizedItemBlock();
MoveItems(rib, offset, rib.ItemCount - offset, newBlock, 0, offset);
newBlock.InsertAfter(rib);
position.Index += block.ContainerCount;
position.Offset = 1;
block = newBlock;
}
uib.InsertBefore(block);
}
// tell generators what happened
if (MapChanged != null)
{
MapChanged(null, index, +1, uib, 0, 0);
}
// tell layout what happened
if (ItemsChanged != null)
{
ItemsChanged(this, new ItemsChangedEventArgs(NotifyCollectionChangedAction.Add, position, 1, 0));
}
}
// "Realize" the item in a block at the given offset, to be
// the given item with corresponding container. This means updating
// the item map data structure so that the item belongs to a Realized block.
// It also requires updating the state of every generator to track the
// changes we make here.
void Realize(UnrealizedItemBlock block, int offset, object item, DependencyObject container)
{
RealizedItemBlock prevR, nextR;
RealizedItemBlock newBlock; // new location of the target item
int newOffset; // its offset within the new block
int deltaCount; // diff between cumulative item count of block and newBlock
// if we're realizing the leftmost item and there's room in the
// previous block, move it there
if (offset == 0 &&
(prevR = block.Prev as RealizedItemBlock) != null &&
prevR.ItemCount < ItemBlock.BlockSize)
{
newBlock = prevR;
newOffset = prevR.ItemCount;
MoveItems(block, offset, 1, newBlock, newOffset, -prevR.ItemCount);
MoveItems(block, 1, block.ItemCount, block, 0, +1);
}
// if we're realizing the rightmost item and there's room in the
// next block, move it there
else if (offset == block.ItemCount - 1 &&
(nextR = block.Next as RealizedItemBlock) != null &&
nextR.ItemCount < ItemBlock.BlockSize)
{
newBlock = nextR;
newOffset = 0;
MoveItems(newBlock, 0, newBlock.ItemCount, newBlock, 1, -1);
MoveItems(block, offset, 1, newBlock, newOffset, offset);
}
// otherwise we need a new block for the target item
else
{
newBlock = new RealizedItemBlock();
newOffset = 0;
deltaCount = offset;
// if target is leftmost item, insert it before remaining items
if (offset == 0)
{
newBlock.InsertBefore(block);
MoveItems(block, offset, 1, newBlock, newOffset, 0);
MoveItems(block, 1, block.ItemCount, block, 0, +1);
}
// if target is rightmost item, insert it after remaining items
else if (offset == block.ItemCount - 1)
{
newBlock.InsertAfter(block);
MoveItems(block, offset, 1, newBlock, newOffset, offset);
}
// otherwise split the block into two, with the target in the middle
else
{
UnrealizedItemBlock newUBlock = new UnrealizedItemBlock();
newUBlock.InsertAfter(block);
newBlock.InsertAfter(block);
MoveItems(block, offset+1, block.ItemCount-offset-1, newUBlock, 0, offset+1);
MoveItems(block, offset, 1, newBlock, 0, offset);
}
}
RemoveAndCoalesceBlocksIfNeeded(block);
// add the new target to the map
newBlock.RealizeItem(newOffset, item, container);
}
// Called when an item is added to the items collection
void OnItemAdded(object item, int index)
{
ValidateAndCorrectIndex(item, ref index);
GeneratorPosition position = new GeneratorPosition(-1,0);
// find the block containing the new item
ItemBlock block = _itemMap.Next;
int offset = index;
while (block != _itemMap && offset >= block.ItemCount)
{
offset -= block.ItemCount;
position.Index += block.ContainerCount;
block = block.Next;
}
position.Offset = offset + 1;
// if it's an unrealized block, add the item by bumping the count
UnrealizedItemBlock uib = block as UnrealizedItemBlock;
if (uib != null)
{
MoveItems(uib, offset, 1, uib, offset+1, 0);
++ uib.ItemCount;
}
// if the item can be added to a previous unrealized block, do so
else if ((offset == 0 || block == _itemMap) &&
((uib = block.Prev as UnrealizedItemBlock) != null))
{
++ uib.ItemCount;
}
// otherwise, create a new unrealized block
else
{
uib = new UnrealizedItemBlock();
uib.ItemCount = 1;
// split the current realized block, if necessary
RealizedItemBlock rib;
if (offset > 0 && (rib = block as RealizedItemBlock) != null)
{
RealizedItemBlock newBlock = new RealizedItemBlock();
MoveItems(rib, offset, rib.ItemCount - offset, newBlock, 0, offset);
newBlock.InsertAfter(rib);
position.Index += block.ContainerCount;
position.Offset = 1;
block = newBlock;
}
uib.InsertBefore(block);
}
if (_traceLog != null)
_traceLog.Add("OnItemAdded {0} index = {1}", TraceLog.IdFor(item), index);
// tell generators what happened
if (MapChanged != null)
{
MapChanged(null, index, +1, null, 0, 0);
}
// tell layout what happened
if (ItemsChanged != null)
{
ItemsChanged(this, new ItemsChangedEventArgs(NotifyCollectionChangedAction.Add, position, 1, 0));
}
}
