private void HandleSameLevelGroupMove( GeneratorNode node, NotifyCollectionChangedEventArgs e )
{
GroupGeneratorNode parentGroup = node.Parent as GroupGeneratorNode;
//Start a NodeHelper on the first child of the node where the move occured.
GeneratorNodeHelper nodeHelper = new GeneratorNodeHelper( node, 0, 0 );
nodeHelper.ReverseCalculateIndex(); //determine index of the node.
//Advance to the first "Group" node (skip the GroupHEaders)
while( !( nodeHelper.CurrentNode is GroupGeneratorNode ) )
{
if( !nodeHelper.MoveToNext() )
throw new DataGridInternalException();
}
//then move up to the removal start point.
if( !nodeHelper.MoveToNextBy( e.OldStartingIndex ) )
{
throw new DataGridInternalException();
}
//remember the current node as the start point of the move (will be used when "extracting the chain")
GeneratorNode startNode = nodeHelper.CurrentNode;
//also remember the index of the node, to calculate range of elements to remove (containers )
int startIndex = nodeHelper.Index;
//then, cumulate the total number of items in the groups concerned
int totalCountRemoved = 0;
node = this.ProcessGroupRemoval( startNode, e.OldItems.Count, false, out totalCountRemoved );
//send a message to the panel to remove the visual elements concerned
GeneratorPosition removeGenPos = this.GeneratorPositionFromIndex( startIndex );
List<DependencyObject> removedContainers = new List<DependencyObject>();
int genCountRemoved = this.RemoveGeneratedItems( startIndex, startIndex + totalCountRemoved - 1, removedContainers );
this.SendRemoveEvent( removeGenPos, startIndex, totalCountRemoved, genCountRemoved, removedContainers );
//reset the node parameter for the "re-addition"
node = ( parentGroup != null ) ? parentGroup.Child : m_firstItem;
if( node == null )
throw new DataGridInternalException();
//Once the chain was pulled out, re-insert it at the appropriate location.
nodeHelper = new GeneratorNodeHelper( node, 0, 0 ); //do not care about the index for what I need
//Advance to the first "Group" node (skip the GroupHEaders)
while( !( nodeHelper.CurrentNode is GroupGeneratorNode ) )
{
if( !nodeHelper.MoveToNext() )
throw new DataGridInternalException();
}
bool insertBefore = nodeHelper.MoveToNextBy( e.NewStartingIndex );
if( insertBefore )
{
if( nodeHelper.CurrentNode == m_firstItem )
{
if( m_startNode == m_firstItem )
{
m_startNode = startNode;
}
m_firstItem = startNode;
}
//reinsert the chain at the specified location.
nodeHelper.InsertBefore( startNode );
}
else
{
nodeHelper.InsertAfter( startNode );
}
//and finally, call to increment the generation count for the generator content
this.IncrementCurrentGenerationCount();
}
private GeneratorPosition HandleSameLevelGroupRemove( GeneratorNode firstChild, out int countRemoved, out int genCountRemoved, out int removeIndex, NotifyCollectionChangedEventArgs e, IList<DependencyObject> removedContainers )
{
GeneratorPosition retval;
countRemoved = 0;
genCountRemoved = 0;
GeneratorNodeHelper nodeHelper = new GeneratorNodeHelper( firstChild, 0, 0 );
nodeHelper.ReverseCalculateIndex();
//Advance to the first "Group" node (skip the GroupHEaders)
while( !( nodeHelper.CurrentNode is GroupGeneratorNode ) )
{
if( !nodeHelper.MoveToNext() )
throw new DataGridInternalException();
}
//then move up to the removal start point.
if( !nodeHelper.MoveToNextBy( e.OldStartingIndex ) )
{
throw new DataGridInternalException();
}
GroupGeneratorNode startNode = nodeHelper.CurrentNode as GroupGeneratorNode;
removeIndex = -1;
//Only fetch the index if the group itself is not "collapsed" or under a collapsed group already
if( ( startNode.IsExpanded == startNode.IsComputedExpanded ) && ( startNode.ItemCount > 0 ) )
{
removeIndex = nodeHelper.Index;
retval = this.GeneratorPositionFromIndex( removeIndex );
}
else
{
retval = new GeneratorPosition( -1, 1 );
}
//retrieve the generator position for the first item to remove.
this.ProcessGroupRemoval( startNode, e.OldItems.Count, true, out countRemoved );
//Clean the chain "isolated" previously
this.NodeFactory.CleanGeneratorNodeTree( startNode );
if( removeIndex != -1 )
{
//remove the appropriate
genCountRemoved = this.RemoveGeneratedItems( removeIndex, removeIndex + countRemoved - 1, removedContainers );
}
return retval;
}