//Xóa từ và nghĩa
        private void removeWordMeaning()
        {
            uDict_list.Clear();

            string fileName = tList.Text + ".txt";
            string filePath = Path.Combine(Environment.CurrentDirectory, @"Topics\", fileName);

            List <string> lines = File.ReadAllLines(filePath).ToList();

            foreach (var line in lines)
            {
                string[]  entries   = line.Split('\t');
                User_Dict new_uDict = new User_Dict();
                new_uDict.Word    = entries[0];
                new_uDict.Meaning = entries[1];
                uDict_list.Add(new_uDict);
            }

            for (int i = 1; i <= lines.Count; i++)
            {
                User_Dict ud = new User_Dict();
                ud.Word = uDict_list[i - 1].Word;
                if (tWrdList.SelectedNode.Text == ud.Word)
                {
                    tWrdList.SelectedNode.Remove();
                    lines.RemoveAt(i - 1);
                    File.WriteAllLines(filePath, lines, Encoding.UTF8);
                }
            }
        }
        //Hàm chỉnh sửa cho từ và nghĩa
        private void editWordMeaning(User_Dict o_UD, string n_word, string n_meaning)
        {
            uDict_list.Clear();
            breakNewLine(n_meaning);

            string linetowrite = string.Format("{0}\t{1}", n_word, n_meaning);
            string fileName    = tList.Text + ".txt";
            string filePath    = Path.Combine(Environment.CurrentDirectory, @"Topics\", fileName);

            List <string> lines = File.ReadAllLines(filePath).ToList();

            string[] arrLine = File.ReadAllLines(filePath);

            foreach (var line in lines)
            {
                string[]  entries   = line.Split('\t');
                User_Dict new_uDict = new User_Dict();
                new_uDict.Word    = entries[0];
                new_uDict.Meaning = entries[1];
                uDict_list.Add(new_uDict);
            }

            if (!checkExistedWord())
            {
                for (int i = 1; i <= uDict_list.Count; i++)
                {
                    if (o_UD.Word == uDict_list[i - 1].Word && o_UD.Meaning == uDict_list[i - 1].Meaning)
                    {
                        arrLine[i - 1] = linetowrite;
                        File.WriteAllLines(filePath, arrLine, Encoding.UTF8);
                    }
                }
            }
            else
            {
                const string message = "Từ này đã tồn tại";
                const string caption = "Thông báo";
                MessageBox.Show(message, caption, MessageBoxButtons.OK, MessageBoxIcon.Information);
                tWord_Box.Focus();
                return;
            }
        }
        //Hàm cập nhật TreeView sau khi chỉnh sửa
        private void editTreeView()
        {
            tWrdList.Nodes.Clear();
            uDict_list.Clear();

            string fileName = tName_Update.Text + ".txt";
            string filePath = Path.Combine(Environment.CurrentDirectory, @"Topics\", fileName);
            //Thêm Root
            TreeNode root = new TreeNode()
            {
                Text = tName_Update.Text
            };

            tWrdList.Nodes.Add(root);

            List <string> lines = File.ReadAllLines(filePath).ToList();

            foreach (var line in lines)
            {
                string[]  entries   = line.Split('\t');
                User_Dict new_uDict = new User_Dict();
                new_uDict.Word    = entries[0];
                new_uDict.Meaning = entries[1];
                uDict_list.Add(new_uDict);
            }
            //Thêm nodes cho root
            for (int i = 0; i < uDict_list.Count; i++)
            {
                TreeNode node = new TreeNode {
                    Text = uDict_list[i].Word
                };
                root.Nodes.Add(node);
            }
            //TreeView tự động sổ ra
            tWrdList.ExpandAll();
        }