asp.net treeview Dynamic binding Database Display data

Suppose you create a table in the database, such as Tb_treeview, as follows

CREATE TABLE Tb_treeview (

ID int NOT NULL,

DisplayName varchar (20),

ParentID int,

URL varchar (100)

);

Insert several data into a table such as:

INSERT into Tb_treeview (1, ' China ', 0, ');

Insert into Tb_treeview (2, ' Anhui Province ', 1, ');

Insert into Tb_treeview (3, ' Hefei ', 2, ');

Insert into Tb_treeview (4, ' Jiangsu Province ', 1, ');

Insert into Tb_treeview (5, ' Nanjing ', 4, ');

INSERT into Tb_treeview (6, ' Hubei province ', 1, ');

As presentation data.

(1), open VS2005, create a new Web site project, add the following code in the Default.aspx.cs file:

...

Using System.Data.SqlClient;

....

DataTable dt = new DataTable ();

public void Page_Load (Object Sender,eventargs e)

{

if (! IsPostBack)

{

Try

{

String constring = "Data source=.; uid=sa;pwd=;D Atabase=master ";

SqlConnection con = new SqlConnection (constring);

Con. Open ();

String strSQL = "SELECT * from Tb_treeview";

SqlDataAdapter da = new SqlDataAdapter (Strsql,con);

Da. Fill (DT);

}

catch (Exception e)

{

}

Finally

{

Con. Close ();

}

Addtreenode (0, (TreeNode) null);

}

}

protected void Addtreenode (int parentid,treenode pnode)

{

TreeNode tn1 = new TreeNode ();

DataView dv= new DataView (DT);

Filter ParentID to get all child nodes of the current node

Dv. RowFilter = "parentid=" +parentid;

foreach (DataRowView DRV in DV)

{

if (pnode==null)

{

Tn1. Text = drv["DisplayName"]. ToString (); The name to display on the node

Tn1. NavigateUrl = drv["url"].  ToString (); Click on the node name to jump to the specified URL page

TREEVIEW1.NODES.ADD (TN1); Add the root node to the TreeView

Tn1. Expanded = true;

Recursive call

Addtreenode (Int32.Parse (drv["id"). ToString ()), TN1);

}

Else

{

TreeNode tn2 = new TreeNode ();

Tn2. Text = drv["DisplayName"]. ToString ();

Tn2. NavigateUrl = drv["url"]. ToString ();

PNODE.CHILDNODES.ADD (TN2);

Tn1. Expanded = true;

Recursive call

Addtreenode (Int32.Parse (drv["id"). ToString ()), TN2);

}

}

}

(2), run in the browser, open the effect as follows

+ China

|+ Anhui Province

| |_ Hefei City

|+ Jiangsu Province

| |_, Nanjing

|+ Hubei Province

It should be explained that in actual development, the data access to the database should be placed in the DAL layer, here is just a simple demo.

If you want to change the node you have selected and the rendering color of the font when you move to that node, you can set this:

<asp:treeview id= "TreeView1" runat= "Server" showlines= "True" cssclass= "Menu" >
<rootnodestyle forecolor= "Red"/>
<selectednodestyle forecolor= "Gray"/>

</asp:TreeView>