private void CommonPreviewMouseMove(MouseEventArgs e, TreeView treeView)
{
if (_startPoint == null) {
return;
}
if (e.LeftButton == MouseButtonState.Pressed && !_IsDragging) {
Point position = e.GetPosition(treeView);
if (Math.Abs(position.X - _startPoint.X) > SystemParameters.MinimumHorizontalDragDistance || Math.Abs(position.Y - _startPoint.Y) > SystemParameters.MinimumVerticalDragDistance) {
if (treeView.SelectedItem != null) {
IInputElement hitelement = treeView.InputHitTest(_startPoint);
TreeViewItem item = treeView.GetTreeViewItemClicked((FrameworkElement)hitelement);
if (item != null) {
StartDrag(e, treeView, item);
}
}
}
}
}