To show summary for a particular row, set the GroupSummaryType and GroupTemplate for the particular JQGridColumn instance.

Then, in the HeaderText property of the respective GroupField use the name of the column (datafield) enclosed with {} to show it in the header.

Refer to the ASPX tab for more details.
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="default.aspx.cs" Inherits="JQSuiteASPNETExample.examples.grid.grouping.multiplefieldheadersummary._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 - multiple field headers</title>
    <!-- The jQuery UI theme that will be used by the grid -->
    <link rel="stylesheet" type="text/css" media="screen" href="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.11.4/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="http://ajax.microsoft.com/ajax/jquery/jquery-2.2.0.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="JQGrid1" DataSourceID="LinqDataSource1" Width="600px" Height="100%">
        <Columns>
            <trirand:JQGridColumn DataField="OrderID" PrimaryKey="true" Width="100" />
            <trirand:JQGridColumn DataField="OrderDate" />
            <trirand:JQGridColumn DataField="CustomerID" DataType="String" />
            <trirand:JQGridColumn DataField="Freight" GroupSummaryType="Sum" GroupTemplate="Sum: {0}" />
            <trirand:JQGridColumn DataField="EmployeeID" Visible="false" />
        </Columns>
        <PagerSettings PageSize="12" />        
        <GroupSettings CollapseGroups="false">
            <GroupFields>
                <trirand:GroupField 
                    DataField="CustomerID" 
                    GroupSortDirection="Asc"
                    HeaderText="CustomerID: &lt;b&gt;{0}&lt;/b&gt;   Sum Freight <b>{Freight}</b>"
                    ShowGroupColumn="True"
                    ShowGroupSummary="True"/>
               <trirand:GroupField                     
                     DataField="EmployeeID" 
                     HeaderText="EmployeeID: &lt;b&gt;{0}&lt;/b&gt;  Sum Freight <b>{Freight}</b>"
                     ShowGroupColumn="false"
                     GroupSortDirection="Asc" />                
            </GroupFields>
        </GroupSettings>
    </trirand:JQGrid> 
    
    <asp:LinqDataSource ID="LinqDataSource1" runat="server" 
        AutoPage="true" AutoSort="true"
        ContextTypeName="GridTest.dbml.NorthWindDataClassesDataContext" 
        Select="new (OrderID, OrderDate, CustomerID, Freight, EmployeeID)" 
        TableName="Orders">
    </asp:LinqDataSource>  
    
    
    <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;

namespace JQSuiteASPNETExample.examples.grid.grouping.multiplefieldheadersummary
{
    public partial class _default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }
    }
}
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" />