private void button1_MouseClick(object sender, MouseEventArgs e) { Form2 tempForm2=new Form2(); tempForm2.StartPosition = FormStartPosition.CenterParent; tempForm2.Show(); TreeNode temoNode = new TreeNode(); temoNode.Text = tempForm2.GetValue(); root.Nodes.Add(temoNode); treeView1.Nodes.Remove(root); treeView1.Nodes.Add(root); tempForm2.Dispose(); }