Send Asynchronous Email in ASP.Net 4.5

This article explains how to send asynchronous mail using a SmtpClient.SendCompleted Event and a SmtpClient.SendAsyncCancel Method in ASP.NET 4.5 for sending the specified message to an SMTP server for delivery as an asynchronous operation.

So, let's proceed with the following procedure:

• Create an Asynchronous Page ASP.NET web page
• Create a SmtpClient.SendCompleted Event and SmtpClient.SendAsyncCancel Method

Creating an Asynchronous Page

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



Next, create the code-behind as follows: The first step is to build an asynchronous page and setting the Async attribute in the Page directive to true, as shown here:

<%@ Page Language="C#" Async="true" %>



Now, in the code behind file SendMail.aspx use the following code.

SendMail.aspx

<%@ Page Title="SendMailAsync|SendAsyncCancel" Async="true" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="SendMail.aspx.cs" Inherits="SendMailAsync.SendMail" %>
<asp:Content ID="Content1" ContentPlaceHolderID="titleContent" runat="server">
    Send Email Asynchronously
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="head" runat="server">
    <script type="text/javascript">
        function validationCheck() {
            var summary = "";
            summary += isvalidName();
            summary += isvalidEmail();
            summary += isvalidSubject();
            summary += isvalidMessage();
            if (summary != "") {
                alert(summary);
                return false;
            }
            else {
                return true;
            }
        }
        function isvalidName() {
            var id;
            var temp = document.getElementById("<%=txtName.ClientID %>");
             id = temp.value;
             if (id == "") {
                 return ("Please enter Name" + "\n");
             }
             else {
                 return "";
             }
         }
         function isvalidEmail() {
             var id;
             var temp = document.getElementById("<%=txtEmail.ClientID %>");
            id = temp.value;
            var re = /\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*/;
            if (id == "") {
                return ("Please Enter Email" + "\n");
            }
            else if (re.test(id)) {
                return "";
            }
            else {
                return ("Email should be in the form [email protected]" + "\n");
            }
        }
        function isvalidSubject() {
            var id;
            var temp = document.getElementById("<%=txtSubject.ClientID %>");
             id = temp.value;
             if (id == "") {
                 return ("Please enter Subject" + "\n");
             }
             else {
                 return "";
             }
         }
         function isvalidMessage() {
             var id;
             var temp = document.getElementById("<%=txtMessage.ClientID %>");
             id = temp.value;
             if (id == "") {
                 return ("Please enter Message" + "\n");
             }
             else {
                 return "";
             }
         }
    </script>
</asp:Content>
<asp:Content ID="Content3" ContentPlaceHolderID="MainContent" runat="server">
    <table style="width: 100%;">
        <tr>
            <td>Name:</td>
            <td>
                <asp:TextBox ID="txtName" runat="server" CssClass="txt"></asp:TextBox></td>
            <td> </td>
        </tr>
        <tr>
            <td>Email ID:</td>
            <td>
                <asp:TextBox ID="txtEmail" runat="server" CssClass="txt"></asp:TextBox></td>
            <td> </td>
        </tr>
        <tr>
            <td>Subject:</td>
            <td>
                <asp:TextBox ID="txtSubject" runat="server" CssClass="txt"></asp:TextBox></td>
            <td> </td>
        </tr>
        <tr>
            <td>Message:</td>
            <td>
                <asp:TextBox ID="txtMessage" runat="server" Height="100px" Width="200px" CssClass="textarea" TextMode="MultiLine"></asp:TextBox>
            </td>
            <td> </td>
        </tr>
        <tr>
            <td></td>
            <td>
                <asp:Button ID="btnSendMail" runat="server" Text="Send Mail" CssClass="button" OnClick="btnSendMail_Click" /></td>
        </tr>
    </table>
</asp:Content>

Create a SmtpClient.SendCompleted Event and SmtpClient.SendAsyncCancel Method

Now, in the code behind file “SendMail.aspx.cs “ use the following code.

SendMail.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
//Using namespaces
using System.IO;
using System.Net;
using System.Net.Mail;
using System.Net.Mime;
using System.Threading;
using System.ComponentModel;
using System.Text;
using System.Web.Util;
namespace SendMailAsync
{
    public partial class SendMail : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            try
            {
                if (!Page.IsPostBack)
                {
                    btnSendMail.Attributes.Add("onclick", "javascript:return validationCheck()");
                }
            }
            catch (Exception ex)
            {
                ShowMessage(ex.Message);
            }
        }
        #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 SendAsyncCancel
        /// <summary>
        /// this code used to SmtpClient.SendAsyncCancel Method
        /// </summary>
        // static bool mailSent = false;
        void SendCompletedCallback(object sender, AsyncCompletedEventArgs e)
        {
            if (e.Cancelled)
            {
                ShowMessage("Send canceled.");
            }
            if (e.Error != null)
            {
                ShowMessage(e.Error.ToString());
            }
            else
            {
                ShowMessage("Email sent successfully");
            }
        }
        #endregion
        #region SendMailAsync
        /// <summary>
        /// this code used to SmtpClient.SendCompleted Event
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void btnSendMail_Click(object sender, EventArgs e)
        {
            try
            {
                MailMessage message = new MailMessage();
                message.From = new MailAddress("[email protected]");
                message.To.Add(txtEmail.Text.Trim());
                message.Subject = txtSubject.Text.Trim();
                message.Body = "<b>Hi:</b>  <br/><br>Name: " +
                                txtName.Text.Trim() + "<br/><br>Message: " +
                                txtMessage.Text.Trim() + "<br/><br>" ;
                message.IsBodyHtml = true;
                message.Priority = MailPriority.High;
                SmtpClient smtp = new SmtpClient("smtp.gmail.com");
                smtp.Port = 587;
                smtp.Credentials = new NetworkCredential("[email protected]", "YouPassword");
                smtp.SendCompleted += new SendCompletedEventHandler(SendCompletedCallback);
                smtp.EnableSsl = true;
                smtp.SendMailAsync(message);
            }
            catch (Exception ex)
            {
                ShowMessage(ex.Message);
            }
            clear();
        }
        #endregion
        #region
        /// <summary>
        /// This Function is used TextBox Empty.
        /// </summary>
        void clear()
        {
            txtName.Text = string.Empty; txtEmail.Text = string.Empty; txtSubject.Text = string.Empty; txtMessage.Text = string.Empty;
            txtName.Focus();
        }
        #endregion
    }
}

Now run the page, it will look like this:

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

 

I hope this article is useful. If you have any other questions then please provide your comments in the following.