You can initiate new row adding from the toolbar ("+" button) or from an external control. In this example, we are using the toolbar ToolBarSettings.ShowAddButton=True

Just handle the RowAdding event on the server. It is callled via ajax request from jqGrid and in the event arguments you will have the values of the new cells to add (eventArgs.RowData). Then just add new row in your datasource, fill it with the respective values and rebind the grid.

In this example we have used ADO.NET as a sample datasource, but this approach will work for any type of datasource you have.
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="default.aspx.cs" Inherits="JQSuiteASPNETExample.examples.editing_data.add_new_row._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 - add new row with dialog</title>
    <!-- The jQuery UI theme that will be used by the grid -->
    <link rel="stylesheet" type="text/css" media="screen" href="" />
    <!-- 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%; }    
    <form id="form1" runat="server">
       <trirand:JQGrid ID="JQGrid1" runat="server" Width="600px" OnRowAdding="JQGrid1_RowAdding">         
                <trirand:JQGridColumn DataField="CustomerID" PrimaryKey="true" />
                <trirand:JQGridColumn DataField="CompanyName" Editable="true" />
                <trirand:JQGridColumn DataField="Phone" Editable="true" />
                <trirand:JQGridColumn DataField="PostalCode" Editable="true" />
                <trirand:JQGridColumn DataField="City" Editable="true" />                
            <ToolBarSettings ShowAddButton="true" />
                Caption="Add a new row" 
                SubmitText="Add the row" 
                Resizable="false" />
       <br /><br />
       <trirand:codetabs runat="server" id="tabs"></trirand:codetabs>    
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using Trirand.Web.UI.WebControls;

namespace JQSuiteASPNETExample.examples.editing_data.add_new_row
    public partial class _default : System.Web.UI.Page
        protected void Page_Load(object sender, EventArgs e)
            if (JQGrid1.AjaxCallBackMode == AjaxCallBackMode.RequestData)
                JQGrid1.DataSource = GetData();

        protected void JQGrid1_RowAdding(object sender, Trirand.Web.UI.WebControls.JQGridRowAddEventArgs e)
            DataTable dt = GetData();
            DataRow row = dt.NewRow();            

            row["CustomerID"] = "NEW" + dt.Rows.Count.ToString();
            row["CompanyName"] = e.RowData["CompanyName"];
            row["Phone"] = e.RowData["Phone"];
            row["PostalCode"] = e.RowData["PostalCode"];
            row["City"] = e.RowData["City"];

            dt.Rows.InsertAt(row, 0);

        protected DataTable GetData()
            if (Session["AddNewRowDialogData"] == null)
                // Create a new Sql Connection and set connection string accordingly
                SqlConnection sqlConnection = new SqlConnection();
                sqlConnection.ConnectionString = ConfigurationManager.ConnectionStrings["SQL2008_661086_trirandEntities"].ConnectionString;

                string sqlStatement = "SELECT CustomerID, CompanyName, Phone, PostalCode, City FROM Customers";

                // Create a SqlDataAdapter to get the results as DataTable
                SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(sqlStatement, sqlConnection);

                // Create a new DataTable
                DataTable dtResult = new DataTable();

                // Fill the DataTable with the result of the SQL statement

                Session["AddNewRowDialogData"] = dtResult;

                return dtResult;
                return Session["AddNewRowDialogData"] as DataTable;
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" />