treeview控件的运用问题 - 黑马程序员技术交流社区

using System;
using System.Linq;
using System.Windows.Forms;
namespace TreeviewSample
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
Load += Form1_Load;
treeView1.BeforeExpand += treeView1_BeforeExpand;
}
/// <summary>
/// 点击节点上的"+"号是触发，这个时机可以加载子节点(便于分级加载数据)(当然也可以在对treeview扩展重写BeforeExpand 并定义事件发出事件便于注册者主动添加节点)
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void treeView1_BeforeExpand(object sender, TreeViewCancelEventArgs e)
{
TreeNodeBase curNode= (TreeNodeBase)e.Node;
//加载节点前清除所有节点 (懒得控制实际可不这么做)
curNode.Nodes.Clear();
//加载子节点从数据库取当前节点的子(不含孙)同时也要取回是否有子信息便于设置Children属性这里不取了直接新建一个
var subode = new TreeNodeBase { NodeId = "01", Text = @"香港", Name = "subNode", Children=true };
curNode.Nodes.Add(subode);
}
void Form1_Load(object sender, EventArgs e)
{
//添加根节点
TreeNodeBase rootNode = new TreeNodeBase {NodeId = "01", Text = @"中国", Name = "rootNode", Children = true};
//添加根节点
treeView1.Nodes.Add(rootNode);
//选中根节点
treeView1.SelectedNode = rootNode;
}
}
/// <summary>
/// 树节点基类(简单扩展下)
/// </summary>
public class TreeNodeBase : TreeNode
{
/// <summary>
/// 节点是否有子
/// </summary>
public bool Children
{
get
{
if (Nodes.Count == 0)return false;
return true;
}
set
{
if (value)
{
if (Nodes.Count == 0)
{
var node = new TreeNodeBase()
{
Name = "muteNode",
};
Nodes.Add(node);
}
}
if (value == false)
{
Nodes.Clear();
}
}
}
/// <summary>
/// 节点对象的ID
/// </summary>
public string NodeId { get; set; }
/// <summary>
/// 父节点ID
/// </summary>
public string ParentNodeId
{
get
{
return ((TreeNodeBase)Parent).NodeId;
}
}
#region 节点基本操作 (完成数据库操作并同步界面显示)
/// <summary>
/// 新增节点
/// </summary>
public void AddSubNode()
{
//1数据库新增节点
//2界面新增节点;
}
/// <summary>
/// 移除节点
/// </summary>
public void RemoveNode()
{
//1数据库移除节点
//2界面移除节点
}
/// <summary>
/// 更新节点
/// </summary>
public void UpdateNode()
{
//1数据库更新节点
//2界面更新节点
}
#endregion
}
}

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