Send Email To Multiple Email Addresses With Attachment Using ASP.NET With C#

Introduction

In my previous article I explained Send Email Using ASP.Net With C#. In this article I will explain how to send multiple emails with attachments. If you don't bother about the code because I just change some codes in my previous article. ! Let's start.

Code

protected void btn_sendemail_Click(object sender, EventArgs e)
{

    string to = Txt_toaddress.Text; //To address
    string from = "fromaddress"; //From address
    string[] Multiple = to.Split(',');
    MailMessage message = new MailMessage();
    message.From = new MailAddress(from);

    foreach (string multiple_email in Multiple)
    {
        message.To.Add(new MailAddress(multiple_email));
    }
    if (FileUpload2.HasFile)//Attaching document
    {
        string FileName = Path.GetFileName(FileUpload2.PostedFile.FileName);
        message.Attachments.Add(new Attachment(FileUpload2.PostedFile.InputStream, FileName));

    }

    string mailbody = Txt_Bodycontent.Text;
    message.Subject = Txt_Subject.Text;
    message.Body = mailbody;
    message.BodyEncoding = Encoding.UTF8;
    message.IsBodyHtml = true;
    SmtpClient client = new SmtpClient("smtp.gmail.com", 587); //Gmail smtp
    System.Net.NetworkCredential basicCredential1 = new
    System.Net.NetworkCredential("fromaddress", "fromaddresspassword");
    client.EnableSsl = true;
    client.UseDefaultCredentials = false;
    client.Credentials = basicCredential1;
    try
    {
        client.Send(message);
    }

    catch (Exception ex)
    {
        throw ex;
    }
}

We must add the following namespace: 

using System.Net;
using System.Net.Mail;
using System.Text;

Multiple Email

The following code will help to split the Comma '"," Separated email in the given textbox( Txt_toaddress.Text ).

string to = Txt_toaddress.Text; //To address
string from = "fromaddress"; //From address
string[] Multiple = to.Split(',');
MailMessage message = new MailMessage();
message.From = new MailAddress(from);

foreach (string multiple_email in Multiple)
{
    message.To.Add(new MailAddress(multiple_email));
}

Attachment

If you want to send an attachment with email you can add the following code. Otherwise you just remove this part in the code.

if (FileUpload2.HasFile)//Attaching document
{
    string FileName = Path.GetFileName(FileUpload2.PostedFile.FileName);
    message.Attachments.Add(new Attachment(FileUpload2.PostedFile.InputStream, FileName));

}

File Upload

If you want to select multiple files in a single file uploader, then you just add AllowMultiple="true". This is one of the option in ASP file upload.

<div>
    <asp:FileUpload runat="server" ID="FileUpload2" AllowMultiple="true" />
</div>

Design

 

 

Output

 

 

Common Error for sending an Email

Check the following reference to solve your 5.5.1 Authentication.

•  SMTP Server Requires a Secure Connection

Reference: You can also see this in my blog:

• Tech Blog Reference

Summary

 

We learned how to send multiple emails with attachment using ASP.NET and C#. I hope this article is useful for all .NET beginners.