//Code by Kiran Reddy
//TreeViewNodes
//First add one parent node to the Tree View control in its properties, select the parent node, to add child nodes to the Tree view add following code to button click events
TreeNode tvnode = new TreeNode("your_Node_Name");
treeView1.SelectedNode.Nodes.Add(tvnode);
treeView1.ExpandAll();
if(treeView1.SelectedNode.Nodes.Count > 1 && treeView1.SelectedNode.ForeColor != Color.Blue)
treeView1.SelectedNode.ForeColor = Color.Green;
//Add siblings to treeview
TreeNode tvnode = new TreeNode("your_Node_Name");
tvnode.ForeColor = Color.Brown;
treeView1.SelectedNode.Parent.Nodes.Add(tvnode);
//Delete selected node
treeView1.SelectedNode.Remove();