数据库表结构：
create table tree(
nd_id integer primary key not null,
nd_parent integer,
nd_text varchar(20)
)
代码文件
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace 数据库_树结构
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
//加载目录树
gettreeview();
}
/// <summary>
/// 向数据库传输数据
/// </summary>
/// <param name="str"></param>
private void connect(string str)
{
string sqlcon = "Data Source = (local);Database = treedb; User ID =sa; PWD = ''";
SqlConnection sqlconn = new SqlConnection(sqlcon);
sqlconn.Open();
SqlCommand com = new SqlCommand(str, sqlconn);
com.ExecuteNonQuery();
sqlconn.Close();
}
/// <summary>
/// 目录树加载
/// </summary>
private void gettreeview()
{
string constr = " Data Source = (local); DataBase = treedb; User ID =sa; PWD = ''";
SqlConnection con = new SqlConnection(constr);
con.Open();
string sqlstr = " select * from tree";
SqlDataAdapter sqldataadapter = new SqlDataAdapter(sqlstr, con);
DataSet ds = new DataSet();
sqldataadapter.Fill(ds, "tree");
con.Close();
// 加载根结点
TreeNode tn = new TreeNode();
tn.Text = "系统文件夹";
tn.Name = "0";
tn.Tag = "0";
treeView1.Nodes.Add(tn);
treeView1.SelectedNode = tn;
// 加载子结点
if (ds != null)
{
foreach (DataRow dr in ds.Tables[0].Rows)
{
tn = new TreeNode();
tn.Text = dr["nd_text"].ToString();
tn.Name = dr["nd_id"].ToString();
tn.Tag = dr["nd_parent"].ToString();
if (treeView1.SelectedNode != tn.Tag)
{
TreeNode[] tn_temp = treeView1.Nodes.Find(dr["nd_parent"].ToString(), true);
if (tn_temp.Length > 0)
{
treeView1.SelectedNode = tn_temp[0];
}
}
treeView1.SelectedNode.Nodes.Add(tn);
}
}
//展开所有结点并且光标返回根结点
treeView1.ExpandAll();
treeView1.SelectedNode = treeView1.TopNode;
}
/// <summary>
/// 添加结点
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void newToolStripMenuItem_Click(object sender, EventArgs e)
{
TreeNode tn = new TreeNode();
tn.Text = "新建文件夹";
int i = Convert.ToInt32(treeView1.SelectedNode.Name);
treeView1.SelectedNode.Nodes.Add(tn);
string str1, str2;
str1 = "declare @a integer,@b integer set @a =(select max(nd_id)+1 from tree) set @b = " + i + "";
str2 = "insert into tree(nd_id,nd_parent,nd_text) values (@a,@b,'新建文件夹') ";
connect(str1 + str2);
treeView1.Nodes.Clear();
gettreeview();
}
/// <summary>
/// 删除结点
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void deleteToolStripMenuItem_Click(object sender, EventArgs e)
{
if (treeView1.SelectedNode.IsExpanded == false)
{
int i = Convert.ToInt32(treeView1.SelectedNode.Name);
treeView1.SelectedNode.Remove();
string str1, str2;
str1 = "declare @a integer set @a = " + i + "";
str2 = "delete from tree where nd_id = @a";
connect(str1 + str2);
}
else
{
MessageBox.Show("此文件夹非空，不能删除", "错误提示！", MessageBoxButtons.OK, MessageBoxIcon.Information);
return;
}
}
/// <summary>
/// 重命名结点
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void renameToolStripMenuItem_Click(object sender, EventArgs e)
{
treeView1.LabelEdit = true;
treeView1.SelectedNode.BeginEdit();
}
/// <summary>
/// 结点重命名后触发的事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void treeView1_AfterLabelEdit(object sender, NodeLabelEditEventArgs e)
{
treeView1.SelectedNode.EndEdit(true);
treeView1.LabelEdit = false;
string nodename = e.Label;
int i = Convert.ToInt32(treeView1.SelectedNode.Name);
string str1, str2;
str1 = "declare @a varchar(20) set @a = '" + nodename + "'";
str2 = " update tree set nd_text = @a where nd_id = " + i + "";
connect(str1 + str2);
}
}
}
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版权声明：本文为CSDN博主「未知数007」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/kinwa007/article/details/2801199