This article shows how to show our records in a tree view using ASP.NET C#.

The following is my Data table design.

design view
Image 1

The following are the records in my Data Table:

table record
Image 2

Here I have Employees and their SupervisorEmployee relationship.

The following is my aspx code:

  1. <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
  3. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  4. <html xmlns="http://www.w3.org/1999/xhtml">
  5. <head runat="server">
  6. <title>Tree View Example in ASP.NET C#</title>
  7. </head>
  8. <body>
  9. <form id="form1" runat="server">
  10. <table cellpadding="4" cellspacing="4" width="50%" align="center" style="background-color: SkyBlue;">
  11. <tr>
  12. <td align="center" style="font-family: Times New Roman; font-size: 14pt; color: Green;">
  13. <h3>
  14. Team Leader and their Team Employee Information</h3>
  15. </td>
  16. </tr>
  17. <tr>
  18. <td style="background: #F5F5F5; padding-left: 30px;">
  19. <asp:TreeView ID="TreeView1" runat="server" ImageSet="XPFileExplorer" NodeIndent="15">
  20. <HoverNodeStyle Font-Underline="True" ForeColor="#6666AA" />
  21. <NodeStyle Font-Names="Tahoma" Font-Size="8pt" ForeColor="Black" HorizontalPadding="2px"
  22. NodeSpacing="0px" VerticalPadding="2px"></NodeStyle>
  23. <ParentNodeStyle Font-Bold="False" />
  24. <SelectedNodeStyle BackColor="#B5B5B5" Font-Underline="False" HorizontalPadding="0px"
  25. VerticalPadding="0px" />
  26. </asp:TreeView>
  27. </td>
  28. </tr>
  29. </table>
  30. </form>
  31. </body>
  32. </html>
Now, my aspx.cs code:
  1. using System;
  2. using System.Configuration;
  3. using System.Data;
  4. using System.Linq;
  5. using System.Web;
  6. using System.Web.Security;
  7. using System.Web.UI;
  8. using System.Web.UI.HtmlControls;
  9. using System.Web.UI.WebControls;
  10. using System.Web.UI.WebControls.WebParts;
  11. using System.Xml.Linq;
  12. using System.Data.SqlClient;
  13. using System.Configuration;
  15. public partial class _Default : System.Web.UI.Page
  16. {
  17. protected void Page_Load(object sender, EventArgs e)
  18. {
  19. if (!this.IsPostBack)
  20. {
  21. DataTable dt = this.GetData("SELECT EmployeeCode, EmployeeName FROM Employee Where EmployeeSupervisorCode=0");
  22. this.PopulateTreeView(dt, 0, null);
  23. }
  24. }
  26. private void PopulateTreeView(DataTable dtParent, int parentId, TreeNode treeNode)
  27. {
  28. foreach (DataRow row in dtParent.Rows)
  29. {
  30. TreeNode child = new TreeNode
  31. {
  32. Text = row["EmployeeName"].ToString(),
  33. Value = row["EmployeeCode"].ToString()
  34. };
  35. if (parentId == 0)
  36. {
  37. TreeView1.Nodes.Add(child);
  38. DataTable dtChild = this.GetData("SELECT EmployeeCode, (EmployeeName+ ', '+ Experience + ', '+ Address) As EmployeeName FROM Employee WHERE EmployeeSupervisorCode = " + child.Value);
  39. PopulateTreeView(dtChild, int.Parse(child.Value), child);
  40. }
  41. else
  42. {
  43. treeNode.ChildNodes.Add(child);
  44. }
  45. }
  46. }
  48. private DataTable GetData(string query)
  49. {
  50. DataTable dt = new DataTable();
  51. string constr = @"Server=MyPC\SqlServer2k8;database=Test;Integrated Security=true;";
  52. using (SqlConnection con = new SqlConnection(constr))
  53. {
  54. using (SqlCommand cmd = new SqlCommand(query))
  55. {
  56. using (SqlDataAdapter sda = new SqlDataAdapter())
  57. {
  58. cmd.CommandType = CommandType.Text;
  59. cmd.Connection = con;
  60. sda.SelectCommand = cmd;
  61. sda.Fill(dt);
  62. }
  63. }
  64. return dt;
  65. }
  66. }
  67. }
Now, run the application:

tree view example
Image 3