This article explains how to send bulk email using ASP.Net 4.5. You can use:

  • ASP .NET web page
  • Grid View
  • HTML Email Templates
  • Gmail SMTP Mail Server

Create a new project using "File" -> "New" -> "Project..." then select web "ASP .Net Web Forms Application". Name it " Bulk Email".

Now in the Design page “Default.aspx” design the web page as in the following screen:

In the Design Source (Default.aspx) write the code as: 

Default.aspx.cs

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true"
CodeBehind="Default.aspx.cs"
 Inherits="BulkEmail._Default" %>

<asp:Content runat="server" ID="FeaturedContent" ContentPlaceHolderID="FeaturedContent">
   
 <section class="featured">
       
 <div class="content-wrapper">
           
 <hgroup class="title">              
               
 <h2>Send Bulk email using asp.net</h2>
           
 </hgroup>
           
 <p>
                To learn more about ASP.NET
           
 </p>
       
 </div>
   
 </section>
</asp:Content>
<asp:Content
 runat="server" ID="BodyContent" ContentPlaceHolderID="MainContent">
      
 <h3>We suggest the following:</h3>
   
 <asp:Panel ID="Panel1" runat="server" Width="100%" ScrollBars="Horizontal">
   
 <p>
      
 <asp:Button ID="btnBind" runat="server" Text="View" OnClick="btnBind_Click" /> <asp:Label
ID="Label1"
 runat="server" Font-Bold="true" ForeColor="Green" Text="Total Customers:">   
</asp:Label><asp:Label ID="lbltotalcount" runat="server" ForeColor="Red" Font
Size
="Larger"></asp:Label> </p>
   
 
       
 <asp:Button ID="btnSend" runat="server" Text="Send" OnClick="btnSend_Click" />
       
 <asp:GridView ID="grvCustomers" runat="server"></asp:GridView>

   
 </asp:Panel>
</asp:Content>

In the Web.config file create the connection string as:

Web.config

<connectionStrings>     
   
<add
 name="ConnectionString"connectionString="Server=localhost;userid=root;password=;Database=
orthwind"providerName="MySql.Data.MySqlClient"/>      

</connectionStrings>

In the code behind file (Default.aspx.cs) write the code as: 

using
 System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

//Using namespaces 
using MySql.Data.MySqlClient;
using System.Configuration;
using System.Text;
using System.Net;
using System.Net.Mail;
using System.Data;

namespace BulkEmail
{
   
 
public partial class _Default : Page
    {
        #region MySqlConnection Connection
       
 
MySqlConnection conn = new
MySqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);

       
 protected void Page_Load(object sender, EventArgs e)
        {
           
 
Try
            {
               
 if (!Page.IsPostBack)
                {

                }
            }
           
 
catch (Exception ex)
            {
                ShowMessage(ex.Message);
            }
        }
        #endregion
        #region show message
       
 
/// <summary>
       
 /// This function is used for show message.
       
 /// </summary>
       
 /// <param name="msg"></param>
       
 void ShowMessage(string msg)
        {
           
 ClientScript.RegisterStartupScript(Page.GetType(), 
"validation", "<script
language='javascript'>alert('"
 + msg + "');</script>");
        }      
 
        #endregion
        #region Bind Data
       
 
/// <summary>
       
 /// This display the data fetched from the table using MySQLCommand,DataSet and
MySqlDataAdapter

       
 /// </summary>
       
 /// <param name="sender"></param>
       
 /// <param name="e"></param>
       
 protected void btnBind_Click(object sender, EventArgs e)
        {
           
 
Try
            {
                conn.Open();
               
 MySqlCommand cmd = new MySqlCommand("Select
CustomerID,ContactName,Address,Phone,Email from customers"
, conn);
               
 MySqlDataAdapter adp = new MySqlDataAdapter(cmd);
               
 DataSet ds = new DataSet();
                adp.Fill(ds);
                grvCustomers.DataSource = ds;
                grvCustomers.DataBind();
                lbltotalcount.Text = grvCustomers.Rows.Count.ToString();
            }
           
 catch (MySqlException ex)
            {
                ShowMessage(ex.Message);
            }
           
 
Finally
            {
                conn.Close();

            }
            btnBind.Visible =
 false;
        }
        #endregion
        #region Bulk email,GridView,gmail
       
 
/// <summary>
       
 /// this code used to Send Bulk email 
       
 /// </summary>
       
 /// <param name="sender"></param>
        
/// <param name="e"></param>
       
 protected void btnSend_Click(object sender, EventArgs e)
        {
           
 
Try
            {
                lbltotalcount.Text =
 string.Empty;
               
 foreach (GridViewRow grow in grvCustomers.Rows)
               {
                   
 
string strCustomerID = grow.Cells[0].Text.Trim();
                   
 
string strContactName = grow.Cells[1].Text.Trim();
                   
 
string strAddress = grow.Cells[2].Text.Trim();
                   
 
string strPhone = grow.Cells[3].Text.Trim();
                   
 
string strEmail = grow.Cells[4].Text.Trim();                

                   
 
string filename = Server.MapPath("~/Event.html");
                   
 string mailbody = System.IO.File.ReadAllText(filename);
                    mailbody = mailbody.Replace(
"##NAME##", strContactName);
                   
 string to = strEmail;
                   
 
string from = "[email protected]";
                   
 MailMessage message = new MailMessage(from, to);
                    message.Subject =
 "Auto Response Email";
                    message.Body = mailbody;
                    message.BodyEncoding =
 Encoding.UTF8;
                    message.IsBodyHtml =
 true;
                   
 SmtpClient client = new SmtpClient("smtp.gmail.com", 587);
                    System.Net.
NetworkCredential basicCredential = new
System.Net.
NetworkCredential("[email protected]", "Password");
                    client.EnableSsl =
 true;
                   
 client.UseDefaultCredentials = true;
                    client.Credentials = basicCredential;
                   
 try
                    {
                        client.Send(message);
                        ShowMessage(
"Email Sending successfully...!" + strContactName + " &nbsp;");                                           
                    }
                   
 catch (Exception ex)
                    {
                        ShowMessage(ex.Message);
                    }
                } 
            }
           
 
catch (MySqlException ex)
            {
                ShowMessage(ex.Message);
            }
           
 
Finally
            {
                conn.Close();
            }
        }
        #endregion
    }
}

See the following screen for the Default.aspx: Total Customers data bind.

Now, see the following screen for the Default.aspx: send email waiting.

Now, show in the Message box “Email sending successfully”.

Now "Email Account Open" - > "View Email". You’ll see the messages on your inbox. Bulk Sending an E-Mail Using ASP.NET 4.5 with HTML Email Templates and Gmail SMTP Mail Server. I hope this article is useful.