Use instances of the TreeView control in WinForm

Create a new form that requires the following buttons on the form interface

(a TreeView a TextBox three button buttons)

The background code is as follows:

usingSystem;usingSystem.Collections.Generic;usingSystem.ComponentModel;usingSystem.Data;usingSystem.Drawing;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;usingSystem.Windows.Forms;namespacewindowsformsapplication1{ Public Partial classForm1:form { PublicForm1 () {InitializeComponent (); }        Private voidForm1_Load (Objectsender, EventArgs e)            {treeView1.Nodes.Clear (); TreeNode Tree=NewTreeNode ("root node");        TREEVIEW1.NODES.ADD (tree); }        /// <summary>        ///ways to add child nodes/// </summary>         Public voidAddchildcode () {//first determine if the position in the node is selected            if(Treeview1.selectednode = =NULL) {MessageBox.Show ("Please select a node! ","Prompt Information", MessageBoxButtons.OK, messageboxicon.information); }            Else            {                if(TextBox1.Text! ="")                {                    //creates a Node object and initializesTreeNode tmp =NewTreeNode (TextBox1.Text); //to join a child node in the TreeView componentTREEVIEW1.SELECTEDNODE.NODES.ADD (TMP); Treeview1.selectednode=tmp;                Treeview1.expandall (); }                Else{MessageBox.Show ("The textbox component must fill in the node name! ","Prompt Information", MessageBoxButtons.OK, messageboxicon.information); return; }            }        }        /// <summary>        ///ways to add sibling nodes/// </summary>         Public voidaddparent () {Try            {                if(Treeview1.selectednode = =NULL) {MessageBox.Show ("Please select a node! ","Prompt Information", MessageBoxButtons.OK, messageboxicon.information); }                Else                {                    if(TextBox1.Text! =NULL)                    {                        //creates a Node object and initializesTreeNode tmp =NewTreeNode (TextBox1.Text); //to join a sibling node in the TreeView componentTREEVIEW1.SELECTEDNODE.PARENT.NODES.ADD (TMP);                    Treeview1.expandall (); }                    Else{MessageBox.Show ("The textbox component must fill in the node name! ","Prompt Information", MessageBoxButtons.OK, messageboxicon.information); return; }                }            }            Catch{TreeNode RMP=NewTreeNode ("root node");            TREEVIEW1.NODES.ADD (RMP); }        }        /// <summary>        ///Judging mouse click events/// </summary>        /// <param name= "Sender" ></param>        /// <param name= "E" ></param>        Private voidTreeview1_mousedown (Objectsender, MouseEventArgs e) {            //gets whether the right mouse button is clicked            if(E.button = =mousebuttons.right) {contextmenustrip1.show ( This,NewPoint (e.x, e.y)); }        }        /// <summary>        ///Expand Next Node/// </summary>        /// <param name= "Sender" ></param>        /// <param name= "E" ></param>        Private voidButton1_Click (Objectsender, EventArgs e)        {TreeView1.SelectedNode.Expand (); }        /// <summary>        ///Expand All Nodes/// </summary>        /// <param name= "Sender" ></param>        /// <param name= "E" ></param>        Private voidButton2_Click (Objectsender, EventArgs e) {            //locating the root nodeTreeview1.selectednode = treeview1.nodes[0]; //Expand all nodes in the componentTreeView1.SelectedNode.ExpandAll (); }        /// <summary>        ///Collapse All nodes/// </summary>        /// <param name= "Sender" ></param>        /// <param name= "E" ></param>        Private voidButton3_Click (Objectsender, EventArgs e) {            //locating the root nodeTreeview1.selectednode = treeview1.nodes[0]; //shrink all nodes in a componentTreeView1.SelectedNode.Collapse (); }        /// <summary>        ///When you click the "Join child Nodes" menu item on the shortcut menu, the user-defined Addchildcode () method is called/// </summary>        /// <param name= "Sender" ></param>        /// <param name= "E" ></param>        Private voidJoin child node Toolstripmenuitem_click_1 (Objectsender, EventArgs e)        {Addchildcode (); }        /// <summary>        ///Click the "Join Sibling node" menu item on the shortcut menu to invoke the user-defined Addparent () method/// </summary>        /// <param name= "Sender" ></param>        /// <param name= "E" ></param>        Private voidJoin the sibling node Toolstripmenuitem_click_1 (Objectsender, EventArgs e)        {addparent (); }        /// <summary>        ///Click the Delete node menu item on the shortcut menu to delete the node/// </summary>        /// <param name= "Sender" ></param>        /// <param name= "E" ></param>        Private voidDelete Node Toolstripmenuitem_click (Objectsender, EventArgs e) {            if(TreeView1.SelectedNode.Nodes.Count = =0) {treeView1.SelectedNode.Remove (); }            Else{MessageBox.Show ("Please delete the child nodes in this node first! ","Prompt Information", MessageBoxButtons.OK, messageboxicon.information); }        }            }}

Use instances of the TreeView control in WinForm