private void control_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
Keys keyData = e.KeyData;
Keys modifiers = keyData & Keys.Modifiers;
keyData &= ~Keys.Modifiers;
if (keyData == Keys.Up ||
keyData == Keys.Right ||
keyData == Keys.Down ||
keyData == Keys.Left)
{
TNode startElement = Adapters.As <TNode>(m_selectionContext.LastSelected);
if (startElement != null)
{
Rectangle nearestRect;
TNode nearest = FindNearestElement(startElement, keyData, out nearestRect);
if (nearest != null)
{
var selection = new List <TNode>(m_selectionContext.SelectionCount);
selection.AddRange(m_selectionContext.GetSelection <TNode>());
KeysUtil.Select <TNode>(selection, nearest, modifiers);
m_selectionContext.Selection = selection.Cast <object>();
var transformAdapter = AdaptedControl.As <ITransformAdapter>();
if (transformAdapter != null)
{
transformAdapter.PanToRect(nearestRect);
}
}
}
}
}
/// <summary>
/// Handles the PreviewKeyDown event on AdaptedControl, and changes the selection
/// if the user navigates using the keyboard</summary>
/// <param name="sender">Sender</param>
/// <param name="e">Event args</param>
protected virtual void PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
Keys keyData = e.KeyData;
Keys modifiers = keyData & Keys.Modifiers;
keyData &= ~Keys.Modifiers;
if (IsNavigationKey(keyData))
{
List <TNode> oldSelection;
// If the user is reversing direction of a past shift+selection, and they didn't
// overshoot the beginning (i.e., the stack isn't empty), then don't search for
// nodes and instead restore a past selection.
if (modifiers == Keys.Shift &&
OppositeNavigationKeys(m_lastKeyWithShift, keyData) &&
m_shiftKeySelectionStack.Count > 0)
{
oldSelection = m_shiftKeySelectionStack.Pop();
ChangeSelection(oldSelection);
return;
}
// We need to know the current selection now.
oldSelection = new List <TNode>(m_selectionContext.SelectionCount);
oldSelection.AddRange(m_selectionContext.GetSelection <TNode>());
// If the user is doing a shift+selection, then push the current selection on to the
// stack. But if the user chose a new direction, clear the stack first.
bool pushOldSelectionIfSelectionChanges = false;
if (modifiers == Keys.Shift)
{
if (m_lastKeyWithShift != Keys.None && m_lastKeyWithShift != keyData)
{
m_lastKeyWithShift = Keys.None;
m_shiftKeySelectionStack.Clear();
}
pushOldSelectionIfSelectionChanges = true;
}
else
{
m_lastKeyWithShift = Keys.None;
m_shiftKeySelectionStack.Clear();
}
// Do a search from the existing selected nodes, looking only along wires.
var connectedNodes = new HashSet <TNode>();
foreach (TNode startElement in m_selectionContext.GetSelection <TNode>())
{
foreach (TNode connectedNode in FindConnectedNodes(startElement, keyData, modifiers))
{
connectedNodes.Add(connectedNode);
}
}
// If no connected nodes were found, then look for the nearest nodes.
if (connectedNodes.Count == 0)
{
foreach (TNode startElement in m_selectionContext.GetSelection <TNode>())
{
TNode nearestNode = FindNearestNode(startElement, keyData, modifiers);
if (nearestNode != null)
{
connectedNodes.Add(nearestNode);
}
}
}
// If we have new connected nodes then change the selection.
if (connectedNodes.Count > 0)
{
// With this keyboard navigation, the Control key doesn't seem to make sense
// for toggling nodes in the selection.
modifiers &= ~Keys.Control;
var newSelection = new HashSet <TNode>(oldSelection);
KeysUtil.Select(newSelection, connectedNodes, modifiers);
if (!newSelection.SetEquals(oldSelection))
{
ChangeSelection(newSelection);
if (pushOldSelectionIfSelectionChanges)
{
m_lastKeyWithShift = keyData;
m_shiftKeySelectionStack.Push(new List <TNode>(oldSelection));
}
// Attempt to pan, to make sure the newly selected nodes are visible
if (m_transformAdapter != null)
{
Rectangle boundingRect = m_pickingAdapter.GetBounds(newSelection.OfType <object>());
m_transformAdapter.PanToRect(boundingRect);
}
}
}
}
}
