Purvi's Blog

Data Binding in a TreeView in Asp.Net?

In this example, I am showing you how to bind a treeview. Here, I am having a table in database where we store Modules and their sub-modules having parent-child like relationship.
Step-1: Add a TreeView to your .aspx Page.

<asp:TreeView ID=”ModuleTreeView” runat=”server” ShowLines=”true”

PopulateNodesFromClient=”false” BackColor=”#99CCFF” style=”width:100%”

ShowExpandCollapse=”false”>

</asp:TreeView>

Step-2: Add a table named “Module” to your database which will store all modules and sub-modules.

Step-3: Insert some values into your table.

All those modules which do not have any parent modules, their ParentModuleID is set to ’0(Zero)’.

Step-4: Add these following code behind methods to the page.

SqlConnection con = new SqlConnection(“—-Your Connection String—-”);

SqlCommand com;

protected void Page_Load(object sender, EventArgs e)

{

ModuleTreeView.ExpandAll();

FillTreeView();

}

//—– Get all the module details from database —–//

public DataTable GetModuleDetails()

{

com = new SqlCommand(“select ModuleID,ModuleName,ParentModuleID from Module”, con);

SqlDataAdapter da = new SqlDataAdapter(com);

DataTable dt = new DataTable();

da.Fill(dt);

return dt;

}

//—-Method to fill the treeview—–//

public void FillTreeView()

{

DataTable Modules = new DataTable();

Modules = GetModuleDetails();

ModuleTreeView.Nodes.Clear();

PopulateTreeNode(Modules, null, 0);

}

//—– Method to bind the treeview nodes as per the moduleID and ParentModuleID—–//

private void PopulateTreeNode(DataTable ModuleList, TreeNode parent, intparentID)

{

TreeNodeCollection baseNodes;

TreeNode node;

if (parent == null)

{

baseNodes = ModuleTreeView.Nodes;

}

else

{

baseNodes = parent.ChildNodes;

}

foreach (DataRow dtRow in ModuleList.Rows)

{

if (int.Parse(dtRow["ParentModuleID"].ToString()) == parentID)

{

node = new TreeNode();

node.Text = dtRow["ModuleName"].ToString();

node.Value = dtRow["ModuleID"].ToString();

node.SelectAction = TreeNodeSelectAction.Select;

baseNodes.Add(node);

PopulateTreeNode(ModuleList, node, int.Parse(dtRow["ModuleID"].ToString()));

}

}

ModuleTreeView.ExpandAll();

}

Now we are done and we can find the result by debugging the page.

The Final Output: