How to remove duplicate row from treeview ( treenode )?

Question

C++ / C#

how to remove duplicate row using loop

Answer 1

string x = " ";

for (int k = 0; k < node.Nodes[index].Nodes.Count; k++)
            {

                if ( x.Contains(node.Nodes[index].Nodes[k].Text)/*node.Nodes[index].Nodes[k].Text != x*/)
                {
                    node.Nodes[index].Nodes.Remove(node.Nodes[index].Nodes[k]);
                    k--;
                }
                else 
                {
                    
                    x += node.Nodes[index].Nodes[k].Text;

                }
            }

Answer 2

lst.GroupBy(x => x)
.Select(s =>s)