/// <summary>
/// Checks if a new item can be inserted at the focus.
/// </summary>
/// <param name="inner">Inner to use to insert the new item upon return.</param>
/// <param name="index">Index of the new item to insert upon return.</param>
/// <returns>True if a new item can be inserted at the focus.</returns>
public virtual bool IsNewItemInsertable(out IFocusCollectionInner inner, out IFocusInsertionCollectionNodeIndex index)
{
inner = null;
index = null;
bool Result = false;
IFocusNodeState State = Focus.CellView.StateView.State;
IFocusFrame Frame = Focus.CellView.Frame;
if (Frame is IFocusInsertFrame AsInsertFrame)
{
Result = IsNewItemInsertableAtInsertFrame(State, AsInsertFrame, out inner, out index);
}
else if (Focus.CellView is IFocusStringContentFocusableCellView AsStringContentFocusableCellView)
{
Result = IsNewItemInsertableAtStringContentCellView(State, AsStringContentFocusableCellView, out inner, out index);
}
return(Result);
}
private protected virtual bool IsNewItemInsertableAtStringContentCellView(IFocusNodeState state, IFocusStringContentFocusableCellView cellView, out IFocusCollectionInner inner, out IFocusInsertionCollectionNodeIndex index)
{
inner = null;
index = null;
bool Result = false;
if (CaretPosition == 0)
{
Result = IsListExtremumItem(state, cellView, IsFirstFocusableCellView, InsertAbove, out inner, out index);
}
else if (CaretPosition == MaxCaretPosition)
{
Result = IsListExtremumItem(state, cellView, IsLastFocusableCellView, InsertBelow, out inner, out index);
}
return(Result);
}
private protected virtual bool IsNewItemInsertableAtInsertFrame(IFocusNodeState state, IFocusInsertFrame frame, out IFocusCollectionInner inner, out IFocusInsertionCollectionNodeIndex index)
{
inner = null;
index = null;
bool Result = false;
Type InsertType = frame.InsertType;
Debug.Assert(InsertType != Type.Missing);
Debug.Assert(!InsertType.IsInterface);
Debug.Assert(!InsertType.IsAbstract);
// Type InterfaceType = NodeTreeHelper.NodeTypeToInterfaceType(InsertType);
//Node NewItem = NodeHelper.CreateDefaultFromInterface(InterfaceType);
Node NewItem = NodeHelper.CreateDefaultFromType(InsertType);
IFocusCollectionInner CollectionInner = null;
frame.CollectionNameToInner(ref state, ref CollectionInner);
Debug.Assert(CollectionInner != null);
if (CollectionInner is IFocusBlockListInner AsBlockListInner)
{
inner = AsBlockListInner;
if (AsBlockListInner.Count == 0)
{
Pattern NewPattern = NodeHelper.CreateEmptyPattern();
Identifier NewSource = NodeHelper.CreateEmptyIdentifier();
index = CreateNewBlockNodeIndex(state.Node, CollectionInner.PropertyName, NewItem, 0, NewPattern, NewSource);
}
else
{
index = CreateExistingBlockNodeIndex(state.Node, CollectionInner.PropertyName, NewItem, 0, 0);
}
Result = true;
}
else if (CollectionInner is IFocusListInner AsListInner)
{
inner = AsListInner;
index = CreateListNodeIndex(state.Node, AsListInner.PropertyName, NewItem, 0);
Result = true;
}
return(Result);
}
private protected virtual bool IsExtremumCheckParent(IFocusNodeState state, IFocusContentFocusableCellView cellView, System.Func <IFocusNodeState, IFocusContentFocusableCellView, bool> isGoodFocusableCellView, System.Func <int, int> getInsertPosition, out IFocusCollectionInner inner, out IFocusInsertionCollectionNodeIndex index)
{
inner = null;
index = null;
bool Result = false;
IFocusNodeState ParentState = state.ParentState;
if (ParentState != null && isGoodFocusableCellView(state, cellView))
{
Result = IsListExtremumItem(ParentState, cellView, isGoodFocusableCellView, getInsertPosition, out inner, out index);
}
return(Result);
}
private protected virtual bool IsListExtremumItem(IFocusNodeState state, IFocusContentFocusableCellView cellView, System.Func <IFocusNodeState, IFocusContentFocusableCellView, bool> isGoodFocusableCellView, System.Func <int, int> getInsertPosition, out IFocusCollectionInner inner, out IFocusInsertionCollectionNodeIndex index)
{
inner = null;
index = null;
IFocusInner ParentInner = state.ParentInner;
if (ParentInner == null)
{
return(false);
}
Node NewItem;
int BlockPosition;
int ItemPosition;
bool IsHandled = false;
bool Result = false;
switch (ParentInner)
{
case IFocusPlaceholderInner AsPlaceholderInner:
case IFocusOptionalInner AsOptionalInner:
Result = IsExtremumCheckParent(state, cellView, isGoodFocusableCellView, getInsertPosition, out inner, out index);
IsHandled = true;
break;
// Check the parent state if there is a deeper list (typically, for a qualified name, there would be one).
case IFocusListInner AsListInner:
if (IsDeepestList(state))
{
NewItem = NodeHelper.CreateDefaultFromType(AsListInner.InterfaceType);
ItemPosition = (state.ParentIndex as IFocusBrowsingListNodeIndex).Index;
inner = AsListInner;
index = CreateListNodeIndex(inner.Owner.Node, inner.PropertyName, NewItem, getInsertPosition(ItemPosition));
Result = true;
}
else
{
Result = IsExtremumCheckParent(state, cellView, isGoodFocusableCellView, getInsertPosition, out inner, out index);
}
IsHandled = true;
break;
case IFocusBlockListInner AsBlockListInner:
NewItem = NodeHelper.CreateDefaultFromType(AsBlockListInner.InterfaceType);
BlockPosition = (state.ParentIndex as IFocusBrowsingExistingBlockNodeIndex).BlockIndex;
ItemPosition = (state.ParentIndex as IFocusBrowsingExistingBlockNodeIndex).Index;
inner = AsBlockListInner;
index = CreateExistingBlockNodeIndex(inner.Owner.Node, inner.PropertyName, NewItem, BlockPosition, getInsertPosition(ItemPosition));
Result = true;
IsHandled = true;
break;
}
Debug.Assert(IsHandled);
return(Result);
}
