Step1: Drag Treeview control from Navigation controls in Toolbox

<asp:TreeView ID=”TreeView1″ runat=”server” >

</asp:TreeView>

Step2: Create Category table and SubCategory tables in sqlserver to display categories data and subcategories data in tree structure.

Click here to view Category and SubCategory tables

step3: write below function GetCategoriesAndSubcategories in default.aspx.cs and call that function in Treeview load event.

<asp:TreeView ID=”TreeView1″ runat=”server” onload=”TreeView1_Load” >

</asp:TreeView>

protected void TreeView1_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

GetCategoriesAndSubCategories();

}

}

public void GetCategoriesAndSubCategories()

{

string ConnectionString = “Data Source=192.168.1.23;Initial Catalog=Purchase;User;Password=xyz;”;

SqlConnection objConn = new SqlConnection(ConnectionString);

string query = “select CategoryID,CategoryName from tblCategory”;

SqlCommand objCmd = new SqlCommand(query, objConn);

objCmd.CommandType = CommandType.Text;

//Dataset and sqldataAdapter for Categories

DataSet objDsCat = new DataSet();

SqlDataAdapter objDa = new SqlDataAdapter(objCmd);

objConn.Open();

objDa.Fill(objDsCat);

//Getting root nodes Categories

foreach (DataRow rowCat in objDsCat.Tables[0].Rows)

{

TreeNode nodeCat = new TreeNode();

nodeCat.Text = rowCat["CategoryName"].ToString();

nodeCat.Value = rowCat["CategoryID"].ToString();

TreeView1.Nodes.Add(nodeCat);

//Getting SubCategories values from Database using

//CategoryID above nodeCat.value

string querySubcat = “select SubCategoryID,SubCategory from tblSubcategory where CategoryID=” + nodeCat.Value;

SqlCommand objCmd2 = new SqlCommand(querySubcat, objConn);

//Dataset and sqldataAdapter for subcategories

DataSet objDsSubCat = new DataSet();

SqlDataAdapter objDaSubCat = new SqlDataAdapter(objCmd2);

objDaSubCat.Fill(objDsSubCat);

//Getting child nodes SubCategories

foreach (DataRow rowSubcat in objDsSubCat.Tables[0].Rows)

{

TreeNode nodeSubcat = new TreeNode();

nodeSubcat.Text = rowSubcat["SubCategory"].ToString();

nodeSubcat.Value = rowSubcat["SubCategoryID"].ToString();

nodeCat.ChildNodes.Add(nodeSubcat);

}

}

objConn.Close();

}

Getting Treeview Node Value and Text using Treeview SelectedNodeChanged

<asp:TreeView ID=”TreeView1″ runat=”server” onload=”TreeView1_Load”

onselectednodechanged=”TreeView1_SelectedNodeChanged”>

</asp:TreeView>

protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)

{

//getting treeview node value

int categoryID = int.Parse(TreeView1.SelectedNode.Value);

//getting treeview node text

string category = TreeView1.SelectedNode.Text;

}

Happy coding…