jqGrid supports tree-grid mode, where you can display rows of data of the same structure (column definition)
as hierarchial tree structure. In your model, just set the TreeGridSettings.Enabled property to true
and the grid will be assuming tree-mode response from the server (see the Model code tab for details).
This means that in addition to the row data, you need to return data that will help jqGrid determine the hierarchy of the rows.

When selecting rows, you need to specify some or all of the following reserved fields

  • tree_level - the level of the row in the tree hierarchy. 0 is for root row.

  • tree_leaf - if the row is leaf (no child rows). This will make it non-expandable and will have an alternative icon.

  • tree_expanded - if the row is expanded by default or not.

  • tree_parent - the primary key (ID) of the parent row (only applicable for child rows)

  • tree_loaded - true/false - if the tree nodes are already loaded. Can be used to show several levels expanded by default.


You can also control the different images per grid rows - in expanded, collapsed and leaf states. This can be achieved with the following properties available from the TreeGridSettings collection - ExpandedIcon, CollapsedIcon, LeafIcon
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="default.aspx.cs" Inherits="JQSuiteASPNETExample.examples.grid.treegrid.filebrowser._default" %>
<%@ Register Assembly="Trirand.Web" TagPrefix="trirand" Namespace="Trirand.Web.UI.WebControls" %>

<!DOCTYPE html>
<html lang="en-us">
<head id="Head1" runat="server">
    <meta charset="utf-8">
    <title>jqGrid for ASP.NET WebForms - TreeGrid - File Browser example</title>
    <!-- The jQuery UI theme that will be used by the grid -->
    <link rel="stylesheet" type="text/css" media="screen" href="http://code.jquery.com/ui/1.12.1/themes/redmond/jquery-ui.css" />
    <!-- The jQuery UI theme extension jqGrid needs -->
    <link rel="stylesheet" type="text/css" media="screen" href="/themes/ui.jqgrid.css" />
    <!-- jQuery runtime minified -->
    <script src="/js/jquery-3.2.1.min.js" type="text/javascript"></script>    
    <!-- The localization file we need, English in this case -->
    <script src="/js/trirand/i18n/grid.locale-en.js" type="text/javascript"></script>
    <!-- The jqGrid client-side javascript -->
    <script src="/js/trirand/jquery.jqGrid.min.js" type="text/javascript"></script>        
        
    <style type="text/css">    
        body, html { font-size: 80%; }
    </style>
</head>


<body>
    <form id="form1" runat="server">
        
    <trirand:JQGrid runat="server" ID="FileDataGrid" Width="650px" Height="350px">
        <Columns>
            <trirand:JQGridColumn DataField="ID" PrimaryKey="True" Visible="false" />
            <trirand:JQGridColumn DataField="Name" Width="350" Sortable="false" />
            <trirand:JQGridColumn DataField="Size" Width="100" Sortable="false"/>
            <trirand:JQGridColumn DataField="DateCreated" HeaderText="Date Created" Width="100" Sortable="false" />
            <trirand:JQGridColumn DataField="LastModified" HeaderText="Last Modified" Width="100" Sortable="false" />
        </Columns>
        <TreeGridSettings
            Enabled="true"            
            ExpandedIcon="ui-icon-folder-open"
            CollapsedIcon="ui-icon-folder-collapsed"
            LeafIcon="ui-icon-document"
         />
    </trirand:JQGrid>
    
    <br /><br />
    
    <trirand:codetabs runat="server" id="tabs"></trirand:codetabs> 
    
    </form>
</body>
</html>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using Trirand.Web.UI.WebControls;
using System.Collections;

namespace JQSuiteASPNETExample.examples.grid.treegrid.filebrowser
{
    public partial class _default : System.Web.UI.Page
    {
        public class DirectoryEntry
        {
            public string ID { get; set; }
            public bool IsDir { get; set; }
            public string Name { get; set; }
            public string Size { get; set; }
            public string DateCreated { get; set; }
            public string LastModified { get; set; }
            public bool tree_expanded { get; set; }
            public bool tree_leaf { get; set; }
            public int tree_level { get; set; }
            public string tree_parent { get; set; }
        }

        protected void Page_Load(object sender, EventArgs e)
        {
            if (FileDataGrid.AjaxCallBackMode == AjaxCallBackMode.RequestData)
            {
                string startingPath = Request.MapPath("~/examples");
                JQGridTreeExpandData expandData = FileDataGrid.GetTreeExpandData();
                if (expandData.ParentID != null)
                    // GetDirectoryFrom hash returns the full path of the folder per its key (in the ID field of the row)
                    startingPath = GetDirectoryFromHash(expandData.ParentID);

                // Take a snapshot of the file system.
                System.IO.DirectoryInfo dir = new System.IO.DirectoryInfo(startingPath);

                IEnumerable dirList = dir.GetDirectories("*.*",
                        System.IO.SearchOption.TopDirectoryOnly);

                IEnumerable fileList = dir.GetFiles("*.*",
                        System.IO.SearchOption.TopDirectoryOnly);

                // ********************************************************************************************
                // when selecting rows, you need to specify some or all of the following reserved fields
                // tree_level - the level of the row in the tree hierarchy. 0 is for root row.
                // tree_leaf - if the row is leaf (no child rows). This will make it non-expandable and will have an alternative icon
                // tree_expanded - if the row is expanded by default or not
                // tree_parent - the primary key (ID) of the parent row (only applicable for child rows)
                // tree_loaded - true/false - if the tree nodes are already loaded. Can be used to show several levels expanded by default.
                // ********************************************************************************************
                var dirs = from directory in dirList
                           orderby directory.Name
                           select new DirectoryEntry
                           {
                               // Use Hashtable to make sure there is unique key per folder fullname
                               ID = AddDirectoryToHash(directory.FullName),
                               IsDir = true,
                               Name = "" + directory.Name + "",
                               Size = "[dir]",
                               DateCreated = directory.CreationTime.ToString("d"),
                               LastModified = directory.LastWriteTime.ToString("d"),
                               tree_parent = expandData.ParentID,
                               tree_expanded = false,
                               tree_leaf = false,
                               tree_level = expandData.ParentLevel + 1
                           };
                var files = from file in fileList
                            orderby file.Name
                            select new DirectoryEntry
                            {
                                // ID is the primary key and must be set to an unique key
                                // GUIDs can be used without the "-" - not allowed for IDs in HTML
                                ID = Guid.NewGuid().ToString().Replace("-", ""),
                                IsDir = false,
                                Name = file.Name,
                                Size = file.Length.ToString(),
                                DateCreated = file.CreationTime.ToString("d"),
                                LastModified = file.LastWriteTime.ToString("d"),
                                tree_parent = expandData.ParentID,
                                tree_leaf = true,
                                tree_level = expandData.ParentLevel + 1
                            };

                var allFilesAndFolders = files.Concat(dirs)
                                              .AsQueryable()
                                              .OrderBy(f => f.Name)
                                              .OrderBy(f => f.IsDir == false);

                FileDataGrid.DataSource = allFilesAndFolders;
                FileDataGrid.DataBind();
            }

        }

        private string AddDirectoryToHash(string fullName)
        {
            Hashtable directoryHash = new Hashtable();
            if (Session["directoryHash"] != null)
                directoryHash = Session["directoryHash"] as Hashtable;

            string key = directoryHash.Count.ToString();
            directoryHash.Add(key, fullName);

            Session["directoryHash"] = directoryHash;

            return key;
        }

        private string GetDirectoryFromHash(string key)
        {
            Hashtable directoryHash = new Hashtable();
            if (Session["directoryHash"] != null)
                directoryHash = Session["directoryHash"] as Hashtable;

            return directoryHash[key] as string;
        }
    }
}
Switch theme:


Theming is based on the very popular jQuery ThemeRoller standard. This is the same theming mechanism used by jQuery UI and is now a de-facto standard for jQuery based components. The benefits of using ThemeRoller are huge. We can offer a big set of ready to use themes created by professional designers, including Windows-like themes (Redmond), Apple-like theme (Cupertino), etc. In addition to that any jQuery UI controls on the same page will pick the same theme.

Last, but not least, you can always roll your own ThemeRoller theme, using the superb Theme Editor

To use a theme, simply reference 2 Css files in your Html <head> section - the ThemeRoller theme you wish to use, and the jqGrid own ThemeRoller Css file. For example (Redmond theme):

<link rel="stylesheet" type="text/css" media="screen" href="/themes/redmond/jquery-ui-1.8.2.custom.css" />
<link rel="stylesheet" type="text/css" media="screen" href="/themes/ui.jqgrid.css" />