private void SetCurrentExtendedMultiSelectIndex(
int newCaret, bool extendFromAnchor, bool preserveSelection, ModifySelectionAction selectCaretAction, bool select)
{
if (!GetStyleFlag(VTCStyleFlags.ExtendedMultiSelect) ||
!IsHandleCreated)
{
return;
}
// We fire off a lot of messages in this routine. Go ahead and use DefWindowProc to
// bypass all of the extra handling done in the various subclassing routines (WinForms and us)
var hWnd = Handle;
var itemCount = (int)NativeMethods.SendMessage(hWnd, NativeMethods.LB_GETCOUNT, 0, 0);
// Get the starting caret
var startCaret = CaretIndex;
var caretInitiallySelected = IsSelected(newCaret);
// Get the initial anchor position
var anchor = newCaret;
if (extendFromAnchor)
{
anchor = AnchorIndex;
if (anchor < 0)
{
extendFromAnchor = false;
anchor = newCaret;
}
}
if ((anchor == newCaret && !preserveSelection) ||
startCaret == newCaret)
{
SetSelected(newCaret, true);
}
else
{
// We're moving toward the anchor (the first two cases here), then the
// remaining items are generally cleared with the !preverseSelection code
// below, but we need to clear between the old and new carets even if we're
// preserving selection elsewhere or things look really weird.
if (newCaret >= anchor &&
startCaret > newCaret &&
startCaret > anchor)
{
if (preserveSelection && extendFromAnchor)
{
SetSelectionRange(newCaret + 1, startCaret, false);
}
}
else if (newCaret <= anchor &&
startCaret < newCaret &&
startCaret < anchor)
{
if (preserveSelection && extendFromAnchor)
{
SetSelectionRange(startCaret, newCaret - 1, false);
}
}
else
{
// Select all items between the old and the new carets, inclusive. Not all of these
// items will be selectable items for multicolumn trees with blank expansions. However,
// these items will be filtered when the selected items are enumerated. We have to handle
// this state regardless because blocking the listbox from reaching this state when the
// user selects items with the mouse is extremely difficult (basically impossible). We
// could block here, but it is not worth creating the ColumnItemEnumerator.
SetSelectionRange(Math.Min(newCaret, startCaret), Math.Max(newCaret, startCaret), select);
}
}
if (!preserveSelection)
{
var keepSelTop = Math.Min(anchor, newCaret);
var keepSelBottom = Math.Max(anchor, newCaret);
// Use selitemrangeex with the lowest number last to clear
if (keepSelTop > 0)
{
SetSelectionRange(0, keepSelTop - 1, false);
}
if (keepSelBottom < itemCount - 1)
{
SetSelectionRange(keepSelBottom + 1, itemCount - 1, false);
}
}
switch (selectCaretAction)
{
case ModifySelectionAction.Clear:
if (IsSelected(newCaret))
{
SetSelected(newCaret, false);
}
else if (!caretInitiallySelected)
{
selectCaretAction = ModifySelectionAction.None; // nothing happened to the caret
}
break;
case ModifySelectionAction.Select:
if (!IsSelected(newCaret))
{
SetSelected(newCaret, true);
}
else if (caretInitiallySelected)
{
selectCaretAction = ModifySelectionAction.None; // nothing happened to the caret
}
break;
case ModifySelectionAction.Toggle:
if (caretInitiallySelected)
{
goto case ModifySelectionAction.Clear;
}
else
{
goto case ModifySelectionAction.Select;
}
}
// Some of the calls above will move the anchor index. Back sure it's where we want it.
if (anchor != AnchorIndex)
{
AnchorIndex = anchor;
}
CaretIndex = newCaret;
DoSelectionChanged();
FireWinEventsForSelection(extendFromAnchor, preserveSelection, selectCaretAction);
}
/// <summary>
/// Fires WinEvents for given selection change.
/// </summary>
private void FireWinEventsForSelection(bool extendFromAnchor, bool preserveSelection, ModifySelectionAction caretAction)
{
if (GetStateFlag(VTCStateFlags.RestoringSelection))
{
return; // no events if we're restoring selection.
}
if (SelectionCount == 1)
{
// if there's currently only one thing selected, we know we should fire a regular selection event.
if (VirtualTreeAccEvents.ShouldNotify(VirtualTreeAccEvents.eventObjectSelection, this))
{
VirtualTreeAccEvents.Notify(
VirtualTreeAccEvents.eventObjectSelection, CurrentIndex,
CurrentColumn, this);
}
}
else if (extendFromAnchor)
{
if (VirtualTreeAccEvents.ShouldNotify(VirtualTreeAccEvents.eventObjectSelectionWithin, this))
{
// we extended selection from the anchor position, this constitutes a significant change in selection
// state, so we fire selection within from the tree control, and let clients query us for the result.
// UNDONE: querying currently won't work because we need a way to return an IEnumVariant from IAccessible::get_accSelection.
// We just fire selection for the caret instead.
// VirtualTreeAccEvents.Notify(VirtualTreeAccEvents.eventObjectSelectionWithin, VirtualTreeConstant.NullIndex,
// VirtualTreeConstant.NullIndex, this);
VirtualTreeAccEvents.Notify(
VirtualTreeAccEvents.eventObjectSelection, CurrentIndex,
CurrentColumn, this);
}
}
else if (preserveSelection)
{
// we're preserving an original selection, which means that we fire either an add or a remove,
// depending on what happened to the caret
switch (caretAction)
{
case ModifySelectionAction.Select:
if (VirtualTreeAccEvents.ShouldNotify(VirtualTreeAccEvents.eventObjectSelectionAdd, this))
{
VirtualTreeAccEvents.Notify(
VirtualTreeAccEvents.eventObjectSelectionAdd, CurrentIndex,
CurrentColumn, this);
}
break;
case ModifySelectionAction.Clear:
if (VirtualTreeAccEvents.ShouldNotify(VirtualTreeAccEvents.eventObjectSelectionRemove, this))
{
VirtualTreeAccEvents.Notify(
VirtualTreeAccEvents.eventObjectSelectionRemove, CurrentIndex,
CurrentColumn, this);
}
break;
case ModifySelectionAction.Toggle:
if (IsSelected(CaretIndex))
{
goto case ModifySelectionAction.Select;
}
else
{
goto case ModifySelectionAction.Clear;
}
case ModifySelectionAction.None:
// Caret position didn't change, but selection still changed overall. This happens, for instance,
// during cross-column selection transfer. We would ideally fire selection within here, for now
// we just fire selection at the caret position anyway.
if (VirtualTreeAccEvents.ShouldNotify(VirtualTreeAccEvents.eventObjectSelectionWithin, this))
{
//VirtualTreeAccEvents.Notify(VirtualTreeAccEvents.eventObjectSelectionWithin, VirtualTreeConstant.NullIndex,
// VirtualTreeConstant.NullIndex, this);
VirtualTreeAccEvents.Notify(
VirtualTreeAccEvents.eventObjectSelection, CurrentIndex,
CurrentColumn, this);
}
break;
}
}
}
/// <summary>
/// Set the multi select caret index on the given item. Calling this with false, false will
/// make the new caret the only selected item.
/// </summary>
/// <param name="newCaret">The new caret position</param>
/// <param name="extendFromAnchor">True to extend the selection from the current anchor position</param>
/// <param name="preserveSelection">True to maintain selected items outside the anchored range</param>
/// <param name="selectCaretAction">Specify how the selection state should be modified</param>
public void SetCurrentExtendedMultiSelectIndex(
int newCaret, bool extendFromAnchor, bool preserveSelection, ModifySelectionAction selectCaretAction)
{
SetCurrentExtendedMultiSelectIndex(newCaret, extendFromAnchor, preserveSelection, selectCaretAction, true);
}
/// <summary>
/// Locate and select an object in this control
/// </summary>
/// <param name="startingBranch">The branch to start the search from, or null for the root branch.</param>
/// <param name="target">The object to locate</param>
/// <param name="selectStyle">The object location style (sent to IBranch.LocateObject locateStyle parameter)</param>
/// <param name="selectData">The object location data (sent to IBranch.LocateObject locateOptions parameter)</param>
/// <param name="extendFromAnchor">Use when SelectionMode is ExtendedMultiSelect. True to extend the selection from the current anchor position</param>
/// <param name="preserveSelection">Use when SelectionMode is ExtendedMultiSelect. True to maintain selected items outside the anchored range</param>
/// <param name="selectCaretAction">Use when SelectionMode is ExtendedMultiSelect. Specify how the selection state should be modified</param>
/// <returns>true if the item was selected</returns>
public bool SelectObject(
IBranch startingBranch, object target, int selectStyle, int selectData, bool extendFromAnchor, bool preserveSelection,
ModifySelectionAction selectCaretAction)
{
if (myTree != null)
{
var locateTarget = myTree.LocateObject(startingBranch, target, selectStyle, selectData);
if (locateTarget.IsValid)
{
var selectionColumn = mySelectionColumn;
var targetColumn = locateTarget.Column;
if (myColumnPermutation != null)
{
targetColumn = myColumnPermutation.GetPermutedColumn(targetColumn);
if (targetColumn == -1)
{
// Item is not currently visible
return false;
}
}
if (GetStyleFlag(VTCStyleFlags.MultiSelect) && ExtendSelectionToAnchors)
{
// If the target column is in the same blank expansion as the
// current column then we leave the selection column alone.
if (myTree.GetBlankExpansion(locateTarget.Row, selectionColumn, myColumnPermutation).AnchorColumn == targetColumn)
{
// Block if condition below
selectionColumn = targetColumn;
}
}
if (selectionColumn != targetColumn)
{
SetSelectionColumn(locateTarget.Column, false);
}
if (GetStyleFlag(VTCStyleFlags.ExtendedMultiSelect))
{
SetCurrentExtendedMultiSelectIndex(locateTarget.Row, extendFromAnchor, preserveSelection, selectCaretAction);
}
else
{
CurrentIndex = locateTarget.Row;
}
return true;
}
}
return false;
}