TreeView

WINFORM界面如下：


本文用了2张表,结构如下：
表province: province_id province_name
表city: city_id city_name province_id

完整代码如下：

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 test
{
public partial class TreeStruc:Form
{
public TreeStruc()
{
InitializeComponent();
}

SqlConnectionconn = new SqlConnection( " server=zhuzy;integratedsecurity=sspi;database=library " );
SqlDataAdapterda;
DataSetds = new DataSet();
SqlCommandcmd;
/// <summary>
/// 自定义节点类，继承于系统的TreeNode类，给节点增加一个IsFirstExpand属性
/// </summary>
public class InheritTreeNode:TreeNode
{
private bool isFirstExpand = true ;

public bool IsFirstExpand // 属性
{
get { return isFirstExpand;}
set {isFirstExpand = value;}
}

public InheritTreeNode(): base (){}
public InheritTreeNode( string text): base (text){}
}

string id = "" ;
private void TreeStruc_Load( object sender,EventArgse)
{
da = new SqlDataAdapter( " selectprovince_id,province_namefromprovince " ,conn);
da.Fill(ds, " province " );
for ( int i = 0 ;i < ds.Tables[ " province " ].Rows.Count;i ++ )
{
InheritTreeNoderoot = new InheritTreeNode(ds.Tables[ " province " ].Rows[i][ 1 ].ToString().Trim());
id = ds.Tables[ " province " ].Rows[i][ 0 ].ToString().Trim();
this .treeView1.Nodes.Add(root);
ReadChileNode(root);
id = "" ; //
}
this .treeView1.SelectedNode = treeView1.Nodes[ 0 ];
}

/// <summary>
/// 读取node的子节点
/// </summary>
private void ReadChileNode(TreeNodenode)
{
da = new SqlDataAdapter( " selectcity_namefromcitywhereprovince_id=' " + id + " ' " ,conn);
da.Fill(ds, " city " );
try
{
for ( int j = 0 ;j < ds.Tables[ " city " ].Rows.Count;j ++ )
{
node.Nodes.Add( new InheritTreeNode(ds.Tables[ " city " ].Rows[j][ 0 ].ToString().Trim()));
}
}
catch (Exceptionex)
{
MessageBox.Show(ex.Message);
}
ds.Tables[ " city " ].Clear(); //
}

/// <summary>
/// 节点展开之前事件
/// </summary>
private void treeView1_BeforeExpand( object sender,TreeViewCancelEventArgse)
{
InheritTreeNodenode = (InheritTreeNode)e.Node; // 获取要选中、展开、折叠或选择的树节点e.Node

if (node != null )
{
// 判断该节点是否首次被展开
if (node.IsFirstExpand)
{
for ( int i = 0 ;i < node.Nodes.Count;i ++ )
{
ReadChileNode(node.Nodes[i]); // 为e.Node下的每个子节点，添加子节点
}
}
}
node.IsFirstExpand = false ;
}

/// <summary>
/// 将文本框输入的内容添加为父节点
/// </summary>
private void btnAddParentNode_Click( object sender,EventArgse)
{
try
{
string strParentNode = this .textBox1.Text.ToString().Trim();
da = new SqlDataAdapter( " selectprovince_namefromprovincewhereprovince_name=' " + strParentNode + " ' " ,conn);
da.Fill(ds, " province_name " );
int nCount = ds.Tables[ " province_name " ].Rows.Count;
if (textBox1.Text.ToString().Trim() != "" )
{
if (nCount == 0 ) // 判断是否存在重复省份
{
da = new SqlDataAdapter( " selectmax(province_id)fromprovince " ,conn);
da.Fill(ds, " id " );

string _max_province_id = ds.Tables[ " id " ].Rows[ 0 ][ 0 ].ToString().Trim();
int nID = Convert.ToInt32(_max_province_id) + 1 ;
string strID = " 00 " + nID.ToString().Trim();

string _insertSQL = " insertintoprovincevalues(' " + strID + " ',' " + strParentNode + " ') " ;
cmd = new SqlCommand(_insertSQL,conn);
conn.Open();
cmd.ExecuteNonQuery();
conn.Close();

this .treeView1.Nodes.Add(strParentNode); // 使新增的节点在TreeView里显示
textBox1.Clear();
textBox1.Focus();
}
else
{
MessageBox.Show( " 当前新增的省份已经存在,请重新输入! " , " 提示 " ,MessageBoxButtons.OK,MessageBoxIcon.Information);
textBox1.Clear();
textBox1.Focus();
}
}
}
catch (Exceptionex)
{
MessageBox.Show(ex.Message);
}
}

/// <summary>
/// 在选择了父节点后，将文本框中的内容添加为其子节点
/// </summary>
string str_insert_province_id = "" ;
string str_insert_city_id = "" ;
private void btnAddChildNode_Click( object sender,EventArgse)
{
try
{
TreeNodenode = this .treeView1.SelectedNode;
string strProvinceName = node.Text;
if (node != null )
{
retunParentNode_ID(strProvinceName);
insertChildNode(node);
textBox1.Clear();
textBox1.Focus();
}
else
{
MessageBox.Show( " 请先选择需要新增城市信息的省份! " , " 提示 " ,MessageBoxButtons.OK,MessageBoxIcon.Information);
textBox1.Clear();
textBox1.Focus();
}
}
catch (Exceptionex)
{
MessageBox.Show(ex.Message);
}
}

/// <summary>
/// 返回当前选择的父节点的province_id
/// </summary>
/// <returns></returns>
private string retunParentNode_ID( string strName)
{
da = new SqlDataAdapter( " selectprovince_idfromprovincewhereprovince_name=' " + strName + " ' " ,conn);
da.Fill(ds, " province_id " );
str_insert_province_id = ds.Tables[ " province_id " ].Rows[ 0 ][ 0 ].ToString().Trim(); // 即将新增的子节点的province_id
return str_insert_province_id;
}
/// <summary>
/// 在当前选择的父节点下新增子节点
/// </summary>
private void insertChildNode(TreeNodeCurrentParentNode)
{
string strChildNode = this .textBox1.Text.ToString().Trim();
try
{
if (textBox1.Text.ToString().Trim() != "" )
{
string strsql = " select*fromcitywhereprovince_id=' " + str_insert_province_id + " ' " ;
da = new SqlDataAdapter(strsql,conn);
da.Fill(ds, " tb " );
int nCount1 = ds.Tables[ " tb " ].Rows.Count;
if (nCount1 == 0 ) // 父节点下没有子节点
{
string _city_id = " 0 " + " 1 " ;
string _insertSQL = " insertintocityvalues(' " + _city_id + " ',' " + strChildNode + " ',' " + str_insert_province_id + " ') " ;

cmd = new SqlCommand(_insertSQL,conn);
conn.Open();
cmd.ExecuteNonQuery();
conn.Close();

CurrentParentNode.Nodes.Add(strChildNode);
textBox1.Clear();
textBox1.Focus();
}
if (nCount1 != 0 ) // 父节点下有子节点
{
da = new SqlDataAdapter( " selectcity_namefromcitywherecity_name=' " + strChildNode + " ' " ,conn);
da.Fill(ds, " city_name " );
int nCount2 = ds.Tables[ " city_name " ].Rows.Count;
if (nCount2 == 0 ) // 不存在相同的子节点
{
string _max_city_id = " selectmax(city_id)fromcitywhereprovince_id=' " + str_insert_province_id + " ' " ;
da = new SqlDataAdapter(_max_city_id,conn);
da.Fill(ds, " city_id " );
str_insert_city_id = ds.Tables[ " city_id " ].Rows[ 0 ][ 0 ].ToString().Trim();
int nID = Convert.ToInt32(str_insert_city_id) + 1 ;
str_insert_city_id = " 0 " + nID.ToString().Trim();

string _insertSQL = " insertintocityvalues(' " + str_insert_city_id + " ',' " + strChildNode + " ',' " + str_insert_province_id + " ') " ;

cmd = new SqlCommand(_insertSQL,conn);
conn.Open();
cmd.ExecuteNonQuery();
conn.Close();

CurrentParentNode.Nodes.Add(strChildNode);
textBox1.Clear();
textBox1.Focus();
}
if (nCount2 != 0 ) // 存在相同的子节点
{
MessageBox.Show( " 已经存在此城市,请重新输入! " , " 提示 " ,MessageBoxButtons.OK,MessageBoxIcon.Information);
textBox1.Clear();
textBox1.Focus();
}
}
}
}
catch (Exceptionex){MessageBox.Show(ex.Message);}}}}

备注：此树只实现2层结构