【www.bbyears.com--Access】
TreeView数据绑定
在ASP.NET中如何实现数据库与TreeView控件的数据绑定呢？花些时间自己编写了一个演示程序，包括有Access数据库，你可复制这两个代码做下测试，测试数据库文件后附下载。
Left.aspx 代码如下：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Left.aspx.cs" Inherits="Left" %>
<script language="javascript">
function chkAll()
{
var chkall= document.all["chkall"];
var chkother= document.getElementsByTagName("input");
for (var i=0;i
if( chkother[i].type=="checkbox")
{
if(chkother[i].id.indexOf("TreeView1")>-1)
{
if(chkall.checked==true)
{
chkother[i].checked=true;
}
else
{
chkother[i].checked=false;
}
}
}
}
}
</script>
Left.aspx.cs代码，与Left.aspx放在同级目录下：
代码如下using System;
using System.Data;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
public partial class Left : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
BindTree();
//InitTree();
}
}
#region 主从表绑定
private void BindTree()
{
DataSet dst = GetTreeViewData();
TreeView1.ShowCheckBoxes = TreeNodeTypes.All;
foreach (DataRow masterRow in dst.Tables["province"].Rows)
{
TreeNode masterNode = new TreeNode((string)masterRow["province"]);
TreeView1.Nodes.Add(masterNode);
foreach (DataRow childRow in masterRow.GetChildRows("Children"))
{
TreeNode childNode =new TreeNode((string)childRow["city"]);
masterNode.Expanded = false;
masterNode.ChildNodes.Add(childNode);
}
}
}
private DataSet GetTreeViewData()
{
string constring = System.Configuration.ConfigurationSettings.AppSettings["ConnectionStr"];
SqlConnection con = new SqlConnection(constring);
SqlDataAdapter daprovince = new SqlDataAdapter("SELECT * FROM province", con);
SqlDataAdapter dacity = new SqlDataAdapter("SELECT * FROM city", con);
DataSet ds = new DataSet();
daprovince.Fill(ds, "province");
dacity.Fill(ds, "city");
ds.Relations.Add("Children", ds.Tables["province"].Columns["provinceid"], ds.Tables["city"].Columns["father"]);
return ds;
}
#endregion
#region 递归绑定同一个表数据
private void InitTree()
{
DataTable dt = GetTreeViewTable();
DataView dv = new DataView(dt);
dv.RowFilter = "ParentID=0";
TreeView1.ShowCheckBoxes = TreeNodeTypes.All;
foreach (DataRowView drv in dv)
{
TreeNode node = new TreeNode();
node.Text = drv["text"].ToString();
node.Value = drv["ID"].ToString();
node.Expanded = false;
TreeView1.Nodes.Add(node);
AddReplies(dt,node);
}
}
private DataTable GetTreeViewTable()
{
string constring = System.Configuration.ConfigurationSettings.AppSettings["ConnectionStr"];
SqlConnection con = new SqlConnection(constring);
SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM treeview", con);
DataTable dt = new DataTable();
da.Fill(dt);
return dt;
}
private void AddReplies(DataTable dt, TreeNode node)
{
DataView dv = new DataView(dt);
dv.RowFilter = "ParentID="" + node.Value + """;
foreach (DataRowView row in dv)
{
TreeNode replyNode = new TreeNode();
replyNode.Text = row["text"].ToString();
replyNode.Value = row["ID"].ToString();
replyNode.Expanded = false;
node.ChildNodes.Add(replyNode);
AddReplies(dt,replyNode);
}
}
#endregion
}
Treeview动态增加节点实例
在asp.net中使用TreeView，如果是静态的增加节点数据，这个很好办，但一般情况下，TreeView是要动态显示菜单项的，大部分都是从XML或Access、SqlServer数据库中加载内容，要从数据库中读出内容动态增加结点，其实也不难，比如以SQL2000的PUBS数据库为例子，我们以树型列表方式取出“作者”做为根结点，再取出对应作者的作品作为子节点，来实现动态展开并加载数据的TreeView，我们可以这样做：
<%@ Import Namespace="System.Data"%>
<%@ Import Namespace="System.Data.SqlClient"%>
<%@ Import Namespace="System.Configuration"%>
<script runat=server>
void Node_Populate(object sender,
System.Web.UI.WebControls.TreeNodeEventArgs e)
{
if(e.Node.ChildNodes.Count == 0)
{
switch( e.Node.Depth )
{
case 0:
FillAuthors(e.Node);
break;
case 1:
FillTitlesForAuthors(e.Node);
break;
}
}
}
void FillAuthors(TreeNode node)
{
string connString = System.Configuration.ConfigurationSettings.
ConnectionStrings["NorthwindConnnection"].ConnectionString;
SqlConnection connection = new SqlConnection(connString);
SqlCommand command = new SqlCommand("Select * From
authors",connection);
SqlDataAdapter adapter = new SqlDataAdapter(command);
DataSet authors = new DataSet();
adapter.Fill(authors);
if (authors.Tables.Count > 0)
{
foreach (DataRow row in authors.Tables[0].Rows)
{
TreeNode newNode = new
TreeNode(row["au_fname"].ToString() + " " +
row["au_lname"].ToString(),
row["au_id"].ToString());
newNode.PopulateOnDemand = true;
newNode.SelectAction = TreeNodeSelectAction.Expand;
node.ChildNodes.Add(newNode);
}
}
}
void FillTitlesForAuthors(TreeNode node)
{
string authorID = node.Value;
string connString = System.Configuration.ConfigurationSettings.
ConnectionStrings["NorthwindConnnection"].ConnectionString;
SqlConnection connection = new SqlConnection(connString);
SqlCommand command = new SqlCommand("Select T.title,
T.title_id From titles T" +
" Inner Join titleauthor TA on
T.title_id = TA.title_id " +
" Where TA.au_id = "" + authorID + """, connection);
SqlDataAdapter adapter = new SqlDataAdapter(command);
DataSet titlesForAuthors = new DataSet();
adapter.Fill(titlesForAuthors);
if (titlesForAuthors.Tables.Count > 0)
{
foreach (DataRow row in titlesForAuthors.Tables[0].Rows)
{
TreeNode newNode = new TreeNode(
row["title"].ToString(), row["title_id"].ToString());
newNode.PopulateOnDemand = false;
newNode.SelectAction = TreeNodeSelectAction.None;
node.ChildNodes.Add(newNode);
}
}
}
</script>
其中，要注意ontreenodepopulate事件，是在展开树结点时发生的，这里自定义了node_populate来检查当前结点的深度，如果是0，就是根结点，于是就调用FillAuthors过程，取出所有的作者，如果深度是1，则是子节点，调用FillTitlesForAuthors过程读取作品信息。其中，要注意动态建立树结点的过程，如下代码：
代码如下 TreeNode newNode = new TreeNode(row["au_fname"].ToString() + " " +row["au_lname"].ToString(),
row["au_id"].ToString());
newNode.PopulateOnDemand = true;
newNode.SelectAction = TreeNodeSelectAction.Expand;
node.ChildNodes.Add(newNode);
从popluateondemand的属性来看，该节点可以动态扩展。