TreeView控件动态生成无限级树

首先注意到了TreeView控件有一个属性TreeNodeSrc
这个属性可以指定一个固定格式的xml文件
<?xml version="1.0" encoding="utf-8" ?>
<TREENODES>
<TREENODE text="aaaaaaaa" CheckBox="true"></TREENODE>
<TREENODE text="bbbbbbbb" CheckBox="true"></TREENODE>
<TREENODE text="cccccccccc" EXPANDED="true" CheckBox="true">
<TREENODE text="ddddddddd" CheckBox="true"></TREENODE>
<TREENODE text="eeeeeeeee" CheckBox="true"></TREENODE>
</TREENODE>
<TREENODE text="fffffffffffff" CheckBox="true"></TREENODE>
</TREENODES>于是就想把数据库里的文件读出来写入一个xml文件中，然后再进行绑定
既然是无限级菜单，肯定要用到递归来实现，于是就写了一个如下的递归算法
private void CreateXml(XmlDocument objXMLDoc, XmlElement objRootElem, int belong)
{
//Get DataSet 这里的DataSet具体获取方法我省略掉了
DataSet ds = new DataSet();

foreach(DataRow dr in ds.Tables[0].Rows)
{
//Create ChildNode TreeNode
XmlElement objXmlElem = objXMLDoc.CreateElement("TREENODE");
objRootElem.AppendChild(objXmlElem);

//Create Attributes Text
XmlAttribute objXmlAttText = objXMLDoc.CreateAttribute("Text");
objXmlAttText.Value = dr["text"].ToString().Trim();
objXmlElem.SetAttributeNode(objXmlAttText);

//Create Attributes CheckBox
XmlAttribute objXmlAttCB = objXMLDoc.CreateAttribute("CheckBox");
objXmlAttCB.Value = "True";
objXmlElem.SetAttributeNode(objXmlAttCB);

int id = int.Parse(dr["id"].ToString().Trim());
CreateXml(objXMLDoc, objXmlElem, id);
}
}
然后用下面的方法来实现绑定
private void BindXmlTree()
{
//Create Xml File
XmlDocument objXmlDoc = new XmlDocument();

//Insert Xml Declaration
XmlDeclaration objXmlDeclare = objXmlDoc.CreateXmlDeclaration("1.0", "UTF-8", "yes");
objXmlDoc.InsertBefore(objXmlDeclare, objXmlDoc.DocumentElement);

XmlElement objRootElem = objXmlDoc.CreateElement("TREENODES");
objXmlDoc.AppendChild(objRootElem);

CreateXml(objXmlDoc, objRootElem, 0);

objXmlDoc.Save("E:\\TreeMenu.xml");
TreeView2.TreeNodeSrc = "TreeMenu.xml";
}
到最后两行我就停住了，因为问题出现了
生成的objXmlDoc文件不知道用什么方式才能绑定上TreeNodeSrc
我试了试直接 TreeView2.TreeNodeSrc = objXmlDoc;
可是TreeNodeSrc是String型的数据，没办法
有没有什么方法可以不保存这个objXmlDoc文件而直接绑定呢？

于是就换了个办法来实现
TreeView有一个节点控件叫TreeNode，直接把数据给TreeNode上

private void CreateTree(int belong, Microsoft.Web.UI.WebControls.TreeNode rootnode)
{
DataSet ds = new DataSet();

foreach(DataRow dr in ds.Tables[0].Rows)
{
Microsoft.Web.UI.WebControls.TreeNode treenode = new Microsoft.Web.UI.WebControls.TreeNode();
treenode.Text = dr["text"].ToString().Trim();
treenode.CheckBox = true;
treenode.Expanded = true;
rootnode.Nodes.Add(treenode);

int id = int.Parse(dr["id"].ToString().Trim());
CreateTree(id, treenode);
}
}
用的是一样的递归思想，而且我发现这样做还比较简单一些，很多TreeNode自带的属性很方便修改
如果用Xml还要手动去添加每一个属性，麻烦
在PageLoad里触发这个方法
private void Page_Load(object sender, System.EventArgs e)
{
Microsoft.Web.UI.WebControls.TreeNode rootnode = new Microsoft.Web.UI.WebControls.TreeNode();
rootnode.Expanded = true;
TreeView2.Nodes.Add(rootnode);
CreateTree(0, rootnode);
}注意，这里为了实现递归，不得不添加一个空的根节点rootnode

这样就算大致实现了
另，数据库里的数据格式是这样的
-----------------------------------------
id text belong
1 aaaa 0
2 bbbb 0
3 cccc 0
4 dddd 1
5 eeee 2
6 ffff 4

==========================================

private void InitTree(TreeNodeCollection Nds,string parentId)
{
TreeNode tmpNd;
DataRow[] rows = data.Tables[0].Select("ParentId='" + parentId + "'");
foreach(DataRow row in rows)
{
tmpNd = new TreeNode();
tmpNd.ID = row["NodeId"].ToString();
tmpNd.Text = row["NodeName"].ToString();
tmpNd.NavigateUrl = row["Url"].ToString();
Nds.Add(tmpNd);
if (row["NodeId"].ToString()!="2")
InitTree(tmpNd.Nodes, tmpNd.ID);
}

============================================

# re: 利用TreeView控件动态生成无限级树 回复
2006-01-27 00:31 by QuickTech
Private Sub LoadTrv()
Dim Root As New Microsoft.Web.UI.WebControls.TreeNode
Root.Text = "ALL："
Root.ImageUrl = "../images/trv_root.gif"
Root.SelectedImageUrl = "../images/trv_root.gif"
Root.ExpandedImageUrl = "../images/trv_root.gif"

Dim db As New DB
Dim con As SqlClient.SqlConnection = New SqlClient.SqlConnection(db.Constr)
Dim dr As SqlClient.SqlDataReader
Dim SQL As String = "select Floor_value,Floor_Title from basic_floor order by floor_value"
Dim cmd As SqlClient.SqlCommand = New SqlClient.SqlCommand(SQL, con)
con.Open()
dr = cmd.ExecuteReader
While dr.Read
Dim FloorNd As New Microsoft.Web.UI.WebControls.TreeNode
FloorNd.Text = dr("Floor_value") & ":" & dr("Floor_Title")
FloorNd.ImageUrl = "../images/TrvST2.bmp"
FloorNd.SelectedImageUrl = "../images/trvst10.bmp"
FloorNd.ExpandedImageUrl = "../images/trvst1.bmp"
Root.Nodes.Add(FloorNd)
End While
dr.Close()
con.Close()
con.Dispose()
cmd.Dispose()
End Sub