Windows窗体资源管理器Treeview运用

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace prjtest
{
public partial class frmMain : Form
{
public frmMain()
{
InitializeComponent();
}

private void btnAddroot_Click(object sender, EventArgs e)
{
TreeNode node = new TreeNode();
node.Text = "根节点";
tvleft.Nodes.Add(node);
}

private void btnAddchildnode_Click(object sender, EventArgs e)
{
TreeNode TN = tvleft.SelectedNode;
if (TN == null)
{
MessageBox.Show("必须选择一个根节点");
return;
}
TreeNode node = new TreeNode();
node.Text = "子节点";
TN.Nodes.Add(node);
}

private void btnAddbrotherNode_Click(object sender, EventArgs e)
{
TreeNode tn = tvleft.SelectedNode;
if (tn == null)
{
MessageBox.Show("请选择一个节点");
return;
}
TreeNode node= new TreeNode();
node.Text = "兄弟节点";
TreeNode parent = tn.Parent;
if (parent == null)
{
this.tvleft.Nodes.Add(node);
}
else
{
parent.Nodes.Add(node);
}

}

private void btnAddDelectNode_Click(object sender, EventArgs e)
{
TreeNode TN = this.tvleft.SelectedNode;
if (TN == null)
{
MessageBox.Show("请选择一个节点");
}
TreeNode node = new TreeNode();
node.Nodes.Remove(node);
}

}
}