Want to clear the tree view and bind the same database another once

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C#

ASP.NET

hi brothers and sisters i am beginner in this field so please help me i am already binded the database to the tree view but i Want to clear the tree view and bind the same database another once how can i do please help me
i use this but it doesn't work...

TreeView1.Attributes.Clear();


code is

public void loadtreeview(string connection)
        {
            FirstMiniProject.FirstMiniProject f = new FirstMiniProject.FirstMiniProject(connection);
            string sql = string.Format("SELECT name FROM sys.databases WHERE name NOT IN ('master', 'tempdb', 'model', 'msdb')");
            DataTable tab = new DataTable();
            tab = f.loadtable(sql);
            for (int i = 0; i < tab.Rows.Count; i++)
            {
                string root = tab.Rows[i]["name"].ToString();
                TreeView1.Nodes.Add(new TreeNode(root));
                string sql1 = string.Format("USE {0} SELECT name FROM sys.Tables", root);
                DataTable tab1 = new DataTable();
                tab1 = f.loadtable(sql1);
                for (int j = 0; j < tab1.Rows.Count; j++)
                {
                    string child = tab1.Rows[j]["name"].ToString();
                    TreeView1.Nodes[i].ChildNodes.Add(new TreeNode(child));
                }

            }
        }

i want to clear the tree view after that i will call this function once again to bind;;;;