Question

C# treeview里的tag 怎么用 ？

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

namespace treeview1
{
public partial class Form1 : Form
{
string treePoint;
public Form1()
{
InitializeComponent();
}
static string connStr = "Data Source=.;Initial Catalog=student;User ID=sa;Password=123";
private SqlConnection myConn = new SqlConnection(connStr);
private SqlCommand myCmd = new SqlCommand();
private SqlDataAdapter myDA;
private DataTable dt = new DataTable();
private void Form1_Load(object sender, EventArgs e)
{
myDA = new SqlDataAdapter("select * from t_Digui", myConn);
myDA.Fill(dt);
myTv(0, null);
}
//
//造树
//
private void myTv(int parentId, TreeNode upNode)
{
DataView dv = new DataView(dt);
dv.RowFilter = "i_ParentId =" + parentId;
for(int i = 0;i < dv.Count;i++)
{
if (upNode == null)
{
TreeNode newNode = tvType.Nodes.Add(dv[i][1].ToString());
myTv(Int32.Parse(dv[i][0].ToString()), newNode);
}
else
{
TreeNode newNode = upNode.Nodes.Add(dv[i][1].ToString());
myTv(Int32.Parse(dv[i][0].ToString()), newNode);
}
}
}
//获得鼠标点击节点的所有子节点
private void getPoint(int ParentId)
{
DataView dv = new DataView(dt);
dv.RowFilter = "i_ParentId = " + ParentId;
int[] Id = new int[dv.Count];
for (int i = 0; i < dv.Count; i++)
{
Id[i] = Int32.Parse(dv[i][0].ToString());
int newParentId =Int32.Parse( dv[i][0].ToString());
MessageBox.Show(Convert.ToString(dv[i][0].ToString()));
getPoint(newParentId);
}
tvType.Tag = Id;
}
//
//双击节点发生
//
private void tvType_NodeMouseDoubleClick(object sender, TreeNodeMouseClickEventArgs e)
{
treePoint = tvType.SelectedNode.Text; //获得当前节点名字
//获得当前节点的Id
myCmd.CommandText = "Select * from t_Digui where c_Name = '" + treePoint + "'";
myCmd.Connection = myConn;
myConn.Open();
SqlDataReader myReader = myCmd.ExecuteReader();
myReader.Read();
int ParentId = myReader.GetInt32(0);
myConn.Close();
getPoint(ParentId);
}
}
}

我想知道treeview里的tag，可不可以作全局变量？我想将双击父节点获取的所有子节点商品的ID 存在tag里，用作显示信息怎么做？

Answer 1

tag就是给你存任意东西用的　你放进去的东西他都会原样保存　而且不会对其他东西有任何影响　具体用来做什么就看你自己怎么用了

追问

那要怎么用它?比如我
int[] Id = new int[dv.Count];
tvType.Tag = Id;
那tag现在应该就是数组了吧。
那我现在 该怎么从tag里取出我存进去的东西出来？

Answer 2

数据表：
CREATE TABLE CateTable (
[ID] [int] IDENTITY (1, 1) NOT NULL ,
[CateName] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NOT NULL ,
[RootID] [int] NOT NULL ,
[ParentID] [int] NOT NULL
)
GO

存储过程：
CREATE PROCEDURE CateTable_GetList AS
BEGIN
Select
CateID,
CateName,
RootID,
ParentID
From
CateTable
Order By
CateID,RootID,ParentID
END

代码：
private void MainForm_Load(object sender, EventArgs e)
{
//从数据库中读取数据
SqlConnection con = new SqlConnection(ConnString.ConStr);
SqlCommand cmd = new SqlCommand("CateTable_GetList", con);
cmd.CommandType = CommandType.StoredProcedure;
SqlDataAdapter sda = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
try
{
sda.Fill(ds);
}
catch
{
}
finally
{
cmd = null;
con.Close();
}
//往TreeView中添加树节点
//添加根节点
TreeNode tn = new TreeNode();
tn.Text = "种类";
tn.Name = "0";//Name作为ID
tn.Tag = "0";//Tag作为RootID
tn.ImageIndex = 0;
tn.SelectedImageIndex = 0;
tv.Nodes.Add(tn);//该TreeView命名为tv
tv.SelectedNode = tv.TopNode;
//把其他节点加上去
if (ds != null)
{
foreach (DataRow dr in ds.Tables[0].Rows)
{
tn = new TreeNode();
tn.Text = dr["CateName"].ToString();
tn.Name = dr["CateID"].ToString();//Name作为CateID
tn.Tag = dr["RootID"].ToString();//Tag作为RootID
tn.ImageIndex = 1;
tn.SelectedImageIndex = 1;
//判断是否为主节点
if (dr["CateID"].ToString() == dr["RootID"].ToString())
{
//主节点
tv.SelectedNode = tv.TopNode;
}
else
{
//其他节点
if (tv.SelectedNode.Name != dr["ParentID"].ToString())
{
TreeNode[] tn_temp = tv.Nodes.Find(dr["ParentID"].ToString(), true);
if (tn_temp.Length > 0)
{
tv.SelectedNode = tn_temp[0];
}
}
}
tv.SelectedNode.Nodes.Add(tn);
}
tv.ExpandAll();//展开TreeView
tv.SelectedNode = tv.TopNode;
}
}

Answer 3

数据表：
CREATE TABLE CateTable (
[ID] [int] IDENTITY (1, 1) NOT NULL ,
[CateName] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NOT NULL ,
[RootID] [int] NOT NULL ,
[ParentID] [int] NOT NULL
)
GO

存储过程：
CREATE PROCEDURE CateTable_GetList AS
BEGIN
Select
CateID,
CateName,
RootID,
ParentID
From
CateTable
Order By
CateID,RootID,ParentID
END

代码：
private void MainForm_Load(object sender, EventArgs e)
{
//从数据库中读取数据
SqlConnection con = new SqlConnection(ConnString.ConStr);
SqlCommand cmd = new SqlCommand("CateTable_GetList", con);
cmd.CommandType = CommandType.StoredProcedure;
SqlDataAdapter sda = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
try
{
sda.Fill(ds);
}
catch
{
}
finally
{
cmd = null;
con.Close();
}
//往TreeView中添加树节点
//添加根节点
TreeNode tn = new TreeNode();
tn.Text = "种类";
tn.Name = "0";//Name作为ID
tn.Tag = "0";//Tag作为RootID
tn.ImageIndex = 0;
tn.SelectedImageIndex = 0;
tv.Nodes.Add(tn);//该TreeView命名为tv
tv.SelectedNode = tv.TopNode;
//把其他节点加上去
if (ds != null)
{
foreach (DataRow dr in ds.Tables[0].Rows)
{
tn = new TreeNode();
tn.Text = dr["CateName"].ToString();
tn.Name = dr["CateID"].ToString();//Name作为CateID
tn.Tag = dr["RootID"].ToString();//Tag作为RootID
tn.ImageIndex = 1;
tn.SelectedImageIndex = 1;
//判断是否为主节点
if (dr["CateID"].ToString() == dr["RootID"].ToString())
{
//主节点
tv.SelectedNode = tv.TopNode;
}
else
{
//其他节点
if (tv.SelectedNode.Name != dr["ParentID"].ToString())
{
TreeNode[] tn_temp = tv.Nodes.Find(dr["ParentID"].ToString(), true);
if (tn_temp.Length > 0)
{
tv.SelectedNode = tn_temp[0];
}
}
}
tv.SelectedNode.Nodes.Add(tn);
}
tv.ExpandAll();//展开TreeView
tv.SelectedNode = tv.TopNode;
}
}