public void addNodeToShiftMutiList(TreeNode tn) { SelectedTreeNodeInfo tn1 = new SelectedTreeNodeInfo(); tn1.imgIndex = tn.ImageIndex; tn1.tn = tn; tn1.tn.ImageIndex = 3; bool flag = false; foreach (var item in treeNodeList) { if (item.tn == tn) { flag = true; } } if (!flag) { treeNodeList.Add(tn1); } }