Asp.net 2.0 Treeview controls "simple" operations

I have been learning ASP. net2.0 over the past few days. Although it is only a test version, I have heard that it has come out very early. It was just a month ago.

Shame. Her changes are too big, and there is a tree-like control Treeview, which needs to be downloaded and installed by herself in 1.0.

2.0 is improved. Because it is a control, static filling is very easy to use. It is OK to set some properties,

I had to write the code myself if I had to add the code dynamically. The method was similar to 1.0. I studied it for two days and finally got some results. Hey, it feels too good.

Dynamic ....
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The procedure is as follows:
1. Drag a Treeview control from the toolbox to set the following attributes:
Ontreenodepopulate = "node_populate" // call a method in the background
Id = "tree"
>


Value = "0"/>

2. Create a database to store node information. The database table is as follows:

3. dynamically read data. Implemented in the Aspx. CS File
Public void node_populate (Object sender, system. Web. UI. webcontrols. treenodeeventargs E)
{
If (E. node. childnodes. Count = 0) // checks whether the node is the first node.
{
Switch (E. node. Depth) // obtain the node depth
{
Case 0:
Fill_fathers (E. node); // trigger an event and pass the node that triggers the event!
Break;
Case 1:
Fill_childs (E. node );
Break;
}
}
}

Void fill_fathers (treenode node) // list the parent node
{// Create a database connection and cache the data to the dataset tree_father table
String connstring = configurationmanager. connectionstrings

["Englishconnectionstring"]. connectionstring;
Sqlconnection connection = new sqlconnection (connstring );
Sqlcommand command = new sqlcommand ("select father_name from tree_father where

Father_id is null ", connection );
Sqldataadapter adapter = new sqldataadapter (command );
Dataset tree_father = new dataset ();
Adapter. Fill (tree_father );
If (tree_father.tables.count> 0)
{
Foreach (datarow row in tree_father.tables [0]. Rows) // list parent nodes cyclically
{
Treenode newnode = new treenode (row ["father_name"]. tostring ());
// + "" +
// Row ["father_name"]. tostring (),
// Row ["father_id"]. tostring ());
Newnode. populateondemand = true;
Newnode. selectaction = treenodeselectaction. Expand;
Node. childnodes. Add (newnode );
}
}
}

Void fill_childs (treenode node)
{
String author = node. value. tostring ();
String connstring = configurationmanager. connectionstrings

["Englishconnectionstring"]. connectionstring;
Sqlconnection connection = new sqlconnection (connstring); // pay attention to the Data Type !!! Use

Like !!
Sqlcommand command = new sqlcommand ("select father_name, ID from tree_father where

Father_id like '"+ author +"' ", 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 ["father_name"]. tostring ());
Newnode. populateondemand = true;
Newnode. navigateurl = ".../admin/switch. aspx? Classid = "+ row [" ID "]. tostring ();
// Newnode. Target = "mainfram ";
Newnode. selectaction = treenodeselectaction. Select;
Node. childnodes. Add (newnode );
}
}
}
The above example is successfully tested.