protected override void StartDrag(UIElement dragObj, MouseButtonEventArgs e)
{
mContainedNodes.Clear();
base.StartDrag(dragObj, e);
// 计算所有在范围内的节点
int deepestZIndex = -10;
var lt = ContentGrid.TranslatePoint(new Point(0, 0), ParentDrawCanvas);
var rb = ContentGrid.TranslatePoint(new Point(ContentGrid.ActualWidth, ContentGrid.ActualHeight), ParentDrawCanvas);
var nodes = HostNodesContainer.CtrlNodeList;
for (int i = 0; i < nodes.Count; i++)
{
var checkNode = nodes[i];
var loc = checkNode.GetLocation();
var nRight = loc.X + checkNode.GetWidth();
var nBottom = loc.Y + checkNode.GetHeight();
if (lt.X <= loc.X && rb.X >= nRight && lt.Y <= loc.Y && rb.Y >= nBottom)
{
var zIndex = Canvas.GetZIndex(checkNode);
if (deepestZIndex > zIndex)
{
deepestZIndex = zIndex;
}
mContainedNodes.Add(checkNode);
checkNode.CalculateDeltaPt(e);
}
}
Canvas.SetZIndex(this, deepestZIndex - 1);
}
