TreeView Tree Menu Node

The basic operation of the 1 TreeView tree

Using system;using system.collections.generic;using system.componentmodel;using system.data;using System.Drawing;    Use of the Using system.linq;using system.text;using system.threading.tasks;using system.windows.forms;namespace TreeView {        Public partial class Form1:form {public Form1 () {InitializeComponent (); }//Add root node private void Button2_Click (object sender, EventArgs e) {string nodeName = Textb Ox1.            Text;            int LL = nodename.length; if (nodeName! = null && nodename.length > 0) {//treenode represents a node object, TREEVIEW1.NODES.ADD                The return value of (NodeName) is now the name we want to add to the NodeName node.            TreeNode node = TREEVIEW1.NODES.ADD (NodeName); } else {MessageBox.Show ("Please set the node name!            "); }}//Add child node private void Button3_Click (object sender, EventArgs e) {string Nodenam            e = TextBox1.Text; GetUser-selected nodes TreeNode node = Treeview1.selectednode; if (node! = null) {if (Nodename.length > 0) {node.                Nodes.Add (NodeName); } else {MessageBox.Show ("Please set the name of the child node!")                ");            }} else {MessageBox.Show ("Check the root node of the child node you want to add!"); }}//Clear all nodes private void button1_click (object sender, EventArgs e) {DialogResult D R= MessageBox.Show ("Are you sure you want to empty all nodes?"            "," Warning ", Messageboxbuttons.yesno); if (Dr.            ToString () = = "Yes") {treeView1.Nodes.Clear ();  }}//delete the selected node private void Button4_Click (object sender, EventArgs e) {TreeNode nodes            = Treeview1.selectednode;            if (node! = null) {treeView1.SelectedNode.Remove ();    } else {            MessageBox.Show ("Please select the node you want to delete!")            "); }}//Expand the selected node private void Button5_click (object sender, EventArgs e) {if (treeView1 . SelectedNode! = null) {TreeView1.SelectedNode.Expand ();//expand () Method: Expand the node tree//tree View1.SelectedNode.ExpandAll ();            ExpandAll () Method: Expands all descendant nodes} else {MessageBox.Show ("SELECT nodes to expand!"); }}//Close selected "Expand Node" private void Button6_click (object sender, EventArgs e) {if (t            Reeview1.selectednode! = null) {treeView1.SelectedNode.Collapse ();//Close the expanded selected node}            else {MessageBox.Show ("Please select the node you want to close!"); }        }    }}



TreeView Tree Menu Node