How to send a mail with attachment from windows form using C#.Net. || Send an Email using corporate or business email address in C#.Net.

To implement the Email Sending in Windows Application  you need to follow the below steps :

Step1 :
On the File menu, click New Project. Select Windows Forms Application as your project type.
Design the Form using controls from Toolbox.

Step2:
Now open the Form.cs page and write the following source code.

Form.cs Code : 

using System;
using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Net;

using System.Net.Mail;

using System.Text.RegularExpressions;

namespace Sample

{

    public partial class Sample_MailSend : Form

    {

        public AmirAds_MailSend()

        {

            InitializeComponent();

        }

  

        private void Cancel()

        {

            txtFromMail.Text = string.Empty;

            txtMailPassword.Text = string.Empty;

            txtToMail.Text = string.Empty;

            txtCC.Text = string.Empty;

            txtSubject.Text = string.Empty;

            txtAttachments.Text = string.Empty;

            txtBody.Text = string.Empty;

        }

        private void btnSend_Click(object sender, EventArgs e)

        {

            if (txtFromMail.Text == string.Empty || txtMailPassword.Text == string.Empty || txtToMail.Text == string.Empty || txtSubject.Text == string.Empty)

            {

                MessageBox.Show("Please fill all the fields.", "Alert!!");

            }

            else

            {

                string pattern = null;

                pattern = "^([0-9a-zA-Z]([-\\.\\w]*[0-9a-zA-Z])*@([0-9a-zA-Z][-\\w]*[0-9a-zA-Z]\\.)+[a-zA-Z]{2,9})$";

                if (Regex.IsMatch(txtFromMail.Text, pattern) || Regex.IsMatch(txtToMail.Text, pattern) || Regex.IsMatch(txtCC.Text, pattern))

                {

                    System.Net.Mail.MailMessage msg = new System.Net.Mail.MailMessage();

                    msg.From = new MailAddress(txtFromMail.Text);

                    msg.To.Add(txtToMail.Text);//Text Box for To Address

                    if (txtCC.Text != string.Empty)

                    {

                        msg.CC.Add(new MailAddress(txtCC.Text));

                    }

                    msg.Subject = txtSubject.Text; //Text Box for subject

                    msg.IsBodyHtml = true;

                    msg.Body = txtBody.Text;//Text Box for body

                    if (txtAttachments.Text != string.Empty)

                    {

                        System.Net.Mail.Attachment attachment;

                        attachment = new System.Net.Mail.Attachment(txtAttachments.Text);

                        msg.Attachments.Add(attachment);

                    }

                    //msg.Priority = MailPriority.High;

                    System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient("relay-hosting.secureserver.net", 26);

                    client.UseDefaultCredentials = false;

                    client.Credentials = new System.Net.NetworkCredential(txtFromMail.Text, txtMailPassword.Text);

                    client.Port = 26;

                    client.Host = "mail.corporatemail.com ";

                    client.EnableSsl = false;

                    object userstate = msg;

                   

                    try

                    {

                        client.Send(msg);

                        MyMessageBox.ShowBox("Your mail has been sent sucessfully.");

                        this.Close();

                    }

                    catch (Exception ex)

                    {

                        MyMessageBox.ShowBox(ex.Message);

                    }

                    Cancel();

                }

                else

                {

                    MyMessageBox.ShowBox("Invalid email address");

                }

            }

        }

        private void btnCancel_Click(object sender, EventArgs e)

        {

            Cancel();

        }

        private void btnBrowse_Click(object sender, EventArgs e)

        {

            DialogResult res = openFileDialog1.ShowDialog();

            if (res == DialogResult.OK)

            {

                txtAttachments.Text = openFileDialog1.FileName;

            }

        }

       }
}

Step4:
Now build the Solution and Debug it for the output.