private void OnSelectionChangedAction(List <_Control> selectedList)
{
if (selectedList.Count == 0)
{
PropertyGrid.Browse(DesginControl, null);
MessageTextBlock.Text = "可以选择需要添加的元素，或者鼠标选取屏幕上元素删除、移动等操作";
}
else if (selectedList.Count == 1)
{
PropertyGrid.Browse(selectedList[0], selectedList[0].GetProperties());
MessageTextBlock.Text = string.Format("选择了一个{0}对象", selectedList[0].ToString());
}
else
{
PropertyGrid.Browse(null, null);
MessageTextBlock.Text = string.Format("选择了{0}个对象", selectedList.Count);
}
}