C#pictureBox的mousemove事件


        private void pictureBox2_MouseClick(object sender, MouseEventArgs e)
        {
            m_bOperatorLog = false;
            m_bUser = false;
            m_OpenDoor = false;
            m_FiDoor = false;
            Point pt = e.Location;
            
            TreeNode node = dlgSearchTree.treeSearch.GetNodeAt(pt);
            if(node == null)
            {
                return;
            }
            if (node != null)
            {
                dlgSearchTree.treeSearch.SelectedNode = node;
            }
            if (node.Text == "开门记录查询")
            {
                LoadOpenDoorRecord(1);
            }
            else if (node.Text == "识别记录查询")
            {
                LoadFiRecord(1);
            }
            else if (node.Text == "操作记录查询")
            {
                LoadOperateLogReport(1);
            }
            else if (node.Text == "员工查询")
            {
                LoadUser(1);
            }
        }进入程序，点击界面，mousemove事件有时候不触发，在这里下断点，有时候不进这个事件，这是为什么？