A tree that can add unlimited nodes (asp.net)

1. recursive functions
// 'Recursively traverse the self-built directory tree ================================== =
Private void ShowDir (string sZml, string sIndex)
{
System. Data. SqlClient. SqlConnection sqlCon = new System. Data. SqlClient. SqlConnection (connectionString );
String sqlStr = "select * from mltable where mlzml = N'" + sZml + "'";
System. Data. SqlClient. SqlDataAdapter sqlAda = new System. Data. SqlClient. SqlDataAdapter (sqlStr, sqlCon );
System. Data. DataTable Dt = new DataTable ();
SqlAda. Fill (Dt );
Microsoft. Web. UI. WebControls. TreeNode Node1;
String sIndex0;
String sIndex2;
Int theId;

Int sIndex1 = 0; // The last value of the record tree
Foreach (System. Data. DataRow DtDataRow in Dt. Rows)
{
Theid = convert. toint32 (dtdatarow ["mlid"]);
Node1 = new Microsoft. Web. UI. webcontrols. treenode ();
Node1.text = dtdatarow ["mlmc"]. tostring ();
Node1.imageurl = "images/trees/folder.gif ";
Node1.expandedimageurl = "images/trees/folderopen.gif ";
Node1.expanded = false;
Node1.navigateurl = "admin_tree_show.aspx? Theid = "+ theid +" & sindex = "+ sindex +". "+ sindex1.tostring ();
Node1.id = "";
Node1.target = "Main ";
If (sindex = "")
{
Sindex2 = treeview1.nodes. indexof (node1). tostring ();
Sindex0 = sindex2;

}
Else
{

Microsoft. Web. UI. webcontrols. treenode pnode = treeview1.getnodefromindex (sindex );
Pnode. nodes. Add (node1 );
Sindex2 = pnode. nodes. indexof (node1). tostring ();
Sindex0 = sindex + "." + sindex2;
Sindex1 ++; // record the number of leaves under the current tree, that is, the number of current leaves
}
Showdir (dtdatarow ["mlid"]. tostring (), sindex0 );

}
Sqlcon. Close ();

}
// ================================================ ========
2. Bind a directory tree
// Bind the directory tree ================================================== ====
Private void bindtree ()
{

// Treeview1.selectexpands = true;

Microsoft. Web. UI. webcontrols. treenode node1 = new Microsoft. Web. UI. webcontrols. treenode ();
Node1.text = "Management Center ";
Node1.imageurl = "images/trees/folder.gif ";
Node1.expandedimageurl = "images/trees/folderopen.gif ";
Node1.id = "";
Node1.navigateurl = "admin_glzx.aspx ";
Node1.target = "Main ";
Node1.expanded = true;
Treeview1.nodes. Add (node1 );

// Company management ============================================ ===
Microsoft. Web. UI. webcontrols. treenode node2 = new Microsoft. Web. UI. webcontrols. treenode ();
Node2.Text = "company management ";
Node2.ImageUrl = "images/trees/folder.gif ";
Node2.ExpandedImageUrl = "images/trees/folderopen.gif ";
Node2.ID = "";
Node2.NavigateUrl = "Admin_Gsgl.aspx? SIndex = 0.0 ";
Node2.Target = "main ";
Node2.Expanded = false;
Node1.Nodes. Add (Node2 );

Microsoft. Web. UI. WebControls. TreeNode Node21 = new Microsoft. Web. UI. WebControls. TreeNode ();
Node21.Text = "Company Profile ";
Node21.ImageUrl = "images/trees/folder.gif ";
Node21.ExpandedImageUrl = "images/trees/folderopen.gif ";
Node21.ID = "";
Node21.NavigateUrl = "Admin_GsJj.aspx? SIndex = 0.0.0 ";
Node21.Target = "main ";
Node21.expanded = true;
Node2.nodes. Add (node21 );

// Microsoft. Web. UI. webcontrols. treenode node22 = new Microsoft. Web. UI. webcontrols. treenode ();
// Node22.text = "Contact Information ";
// Node22.imageurl = "images/trees/folder.gif ";
// Node22.expandedimageurl = "images/trees/folderopen.gif ";
// Node22.id = "";
// Node22.navigateurl = "admin_detail.htm ";
// Node22.target = "Main ";
// Node22.expanded = true;
// Node2.nodes. Add (node22 );
//

Microsoft. Web. UI. webcontrols. treenode node23 = new Microsoft. Web. UI. webcontrols. treenode ();
Node23.text = "company News ";
Node23.imageurl = "images/trees/folder.gif ";
Node23.ExpandedImageUrl = "images/trees/folderopen.gif ";
Node23.ID = "";
Node23.NavigateUrl = "admin_gsx?aspx? SIndex = 0.0.1 ";
Node23.Target = "main ";
Node23.Expanded = true;
Node2.Nodes. Add (Node23 );

Microsoft. Web. UI. WebControls. TreeNode Node24 = new Microsoft. Web. UI. WebControls. TreeNode ();
Node24.Text = "Company announcement ";
Node24.ImageUrl = "images/trees/folder.gif ";
Node24.ExpandedImageUrl = "images/trees/folderopen.gif ";
Node24.ID = "";
Node24.NavigateUrl = "Admin_GsGg.aspx? SIndex = 0.0.2 ";
Node24.Target = "main ";
Node24.Expanded = true;
Node2.Nodes. Add (Node24 );

Microsoft. Web. UI. WebControls. TreeNode Node25 = new Microsoft. Web. UI. WebControls. TreeNode ();
Node25.Text = "company honor ";
Node25.ImageUrl = "images/trees/folder.gif ";
Node25.ExpandedImageUrl = "images/trees/folderopen.gif ";
Node25.ID = "";
Node25.NavigateUrl = "Admin_GsRy.aspx? SIndex = 0.0.3 ";
Node25.Target = "main ";
Node25.Expanded = true;
Node2.Nodes. Add (Node25 );

Microsoft. Web. UI. WebControls. TreeNode Node26 = new Microsoft. Web. UI. WebControls. TreeNode ();
Node26.Text = "marketing network ";
Node26.ImageUrl = "images/trees/folder.gif ";
Node26.ExpandedImageUrl = "images/trees/folderopen.gif ";
Node26.ID = "";
Node26.NavigateUrl = "Admin_GsYx.aspx? SIndex = 0.0.4 ";
Node26.Target = "main ";
Node26.Expanded = true;
Node2.Nodes. Add (Node26 );

Microsoft. Web. UI. WebControls. TreeNode Node27 = new Microsoft. Web. UI. WebControls. TreeNode ();
Node27.Text = "company image ";
Node27.ImageUrl = "images/trees/folder.gif ";
Node27.ExpandedImageUrl = "images/trees/folderopen.gif ";
Node27.ID = "";
Node27.NavigateUrl = "Admin_GsXx.aspx? SIndex = 0.0.5 ";
Node27.Target = "main ";
Node27.Expanded = true;
Node2.Nodes. Add (Node27 );

Microsoft. Web. UI. WebControls. TreeNode Node28 = new Microsoft. Web. UI. WebControls. TreeNode ();
Node28.text = "Download Area ";
Node28.imageurl = "images/trees/folder.gif ";
Node28.expandedimageurl = "images/trees/folderopen.gif ";
Node28.id = "";
Node28.navigateurl = "admin_xzzq.aspx? Sindex = 0.0.6 ";
Node28.target = "Main ";
Node28.expanded = true;
Node2.nodes. Add (node28 );
// ================================================ ======================================

// Product management ========================================== ================================

String sindex1;
String sindex2;
Microsoft. Web. UI. webcontrols. treenode node3 = new Microsoft. Web. UI. webcontrols. treenode ();
Node3.text = "product management ";
Node3.ImageUrl = "images/trees/folder.gif ";
Node3.ExpandedImageUrl = "images/trees/folderopen.gif ";
Node3.ID = "";
Node3.NavigateUrl = "Admin_Tree_Show.aspx? Theid = 0 & sIndex = 0.1 ";
Node3.Target = "main ";
Node3.Expanded = true;
Node1.Nodes. Add (Node3 );

SIndex1 = TreeView1.Nodes. IndexOf (Node1). ToString (); // root directory
SIndex2 = Node1.Nodes. IndexOf (Node3). ToString (); // product management directory

ShowDir ("0", sIndex1 + "." + sIndex2 );
}
// ================================================ ======================================

3. data table format
3 mlid int 4 0
0 mlmc nvarchar 50 1
0 mlzml nvarchar 50 1
0 mllx int 4 1
0 thedate datetime 8 1