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Sending Mails with attachments using Gmail

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Sending Mails with attachments using Gmail
Download code from here
Many times I came across the question, "how can we send mails with some files as attachments?" and "do we really need to buy a domain of our own to send mail?"or can we send mails using gmail, yahoo or hotmail accounts. So I decided to write this article to try and answer these questions.


Question : Do we need our own domain to send mails?

Answer : No we do not necessarily need our own domain to send mails. You don't need a domain at all, just an SMTP relay that will forward them on for you! Gmail provides us free SMTP service and yahoo, hotmail and other mail engines charge for the service.


Question : Can we send files as an attachment?

Answer : Yes we can; any type of file can be send as attachment if service provider allows it. For example, Gmail does not allow us to send exe files.


Question : Sometimes our code is perfectly fine yet, still, we are not able to send mails. Either we get an error, "failed to send" or "could not connect to the server". What could be the reason?

Answer : The reason is probably because we have some firewall software installed on the system. The solution is to "punch" a hole in the firewall which will allow out-going connections on the appropriate port.

Requirements:

Development Machine Requirements

Dotnet installed on the system VS2005 or above The Downloadable version comes for VS2008
Files to attach with the mails
Client Side Requirements
Dotnet Framework 2.0 or above in which the application is made
Browser to run the Application
Configure firewall to allow out-bound SMTP connections (for Gmail it's port 587, normally for SMTP it's port 25)

Now let's code for functionality. Double click on the button

Create a web application with the name "SendMailWithAttachment". You can even use any name of your choice I am using this for my example.
Add The Following code in the body tag of the Default.aspx page to genrate an interface for the aplication.
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="SendMailWithAttachment._Default" %> 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml" > 
<head runat="server"> 
<title>Send Mail Using Gmail Account With Attachments</title>
</head> <body> 
<form id="Form1" method="post" runat="server"> 
<table borderColor="#339933" cellSpacing="0" cellPadding="4" width="55%" align="center" border="1"> 
<tr> <td> 

<table cellPadding="4" width="70%" align="center" border="0"> 
<tr bgColor="#339933"> <td align="center" colSpan="2"><asp:label id="lblHeader" Runat="server" Font-Bold="True">Gmail Account Details for Sending Mails</asp:label></td> </tr> 
<tr> <td vAlign="middle" align="right" width="40%">Username:</td> <td vAlign="middle" width="60%"> <asp:TextBox ID="txtUserName" runat="server"  Font-Names="Verdana" Font-Size="X-Small" 
Width="350px"></asp:TextBox> 
</td> 
</tr> 
<tr> 
<td vAlign="middle" align="right" width="40%">Password</td> 
<td vAlign="middle" width="60%"> 
<asp:TextBox ID="txtPassword"  Font-Names="Verdana" Font-Size="X-Small" 
Width="350px" runat="server" TextMode="Password"></asp:TextBox> 
</td> 
</tr> 
<tr bgColor="#339933"> 
<td align="center" colSpan="2"><asp:label id="Label1" Runat="server" Font-Bold="True">SMTP Mail with Attachment</asp:label></td> 
</tr> 
<tr> 
<td vAlign="middle" align="right" width="40%">From :</td> 
<td vAlign="middle" width="60%"><asp:textbox id="txtSender" tabIndex="1" runat="server" Font-Names="Verdana" Font-Size="X-Small" 
Width="350px"></asp:textbox></td> 
</tr> 
<tr> 
<td vAlign="middle" align="right">To :</td> 
<td><asp:textbox id="txtReceiver" tabIndex="1" runat="server" Font-Names="Verdana" 
Font-Size="X-Small" Width="350px"></asp:textbox></td> 
</tr> 
<tr> 
<td vAlign="middle" align="right">Cc :</td> 
<td><asp:textbox id="txtCc" tabIndex="1" runat="server" Font-Names="Verdana" Font-Size="X-Small" 
Width="350px"></asp:textbox></td> 
</tr> 
<tr> 
<td vAlign="middle" align="right">Bcc :</td> 
<td><asp:textbox id="txtBcc" tabIndex="1" runat="server" Font-Names="Verdana" Font-Size="X-Small" 
Width="350px"></asp:textbox></td> 
</tr> 
<tr> 
<td vAlign="middle" align="right">Subject :</td> 
<td><asp:textbox id="txtSubject" tabIndex="2" runat="server" Font-Names="Verdana" 
Font-Size="X-Small" Width="350px"></asp:textbox></td> 
</tr> 
<tr> 
<td vAlign="middle" align="right">Format :</td> 
<td><asp:radiobuttonlist id="rblMailFormat" tabIndex="3" runat="server" repeatcolumns="2" repeatdirection="Horizontal"> 
<asp:ListItem Value="Text" Selected="True">Text</asp:ListItem> 
<asp:ListItem Value="HTML">HTML</asp:ListItem> 
</asp:radiobuttonlist></td> 
</tr> 
<tr> 
<td vAlign="middle" align="right">Message :</td> 
<td height="84"> 
<p><asp:textbox id="txtBody" tabIndex="4" runat="server" Font-Names="Verdana" Font-Size="X-Small" 
columns="40" rows="5" textmode="MultiLine" width="350px"></asp:textbox></p> 
</td> 
</tr> 
<tr> 
<td vAlign="middle" align="right">Attachment :</td><td><input id="inpAttachment1" tabIndex="5" type="file" size="53" name="filMyFile" runat="server"></td> </tr> 
<tr> 
<td vAlign="middle" align="right">Attachment :</td> 
<td><input id="inpAttachment2" tabIndex="6" type="file" size="53" name="filMyFile" runat="server"></td> 
</tr> 
<tr> 
<td vAlign="middle" align="right">Attachment :</td> 
<td><input id="inpAttachment3" tabIndex="7" type="file" size="53" name="filMyFile" runat="server"></td> 
</tr> 
<tr> 
<td align="center" colSpan="2"><asp:button id="btnSend" tabIndex="9" runat="server" width="100px" text="Send" onclick="btnSend_Click"></asp:button></td> 
</tr> 
<tr> 
<td align="center" colSpan="2"><asp:Label ID="lblMessage" Runat="server"></asp:Label> 
</td> 
</tr> 
</table> 
</td> 
</tr> 
</table> 
</form> 
</body> 
</html>

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Now Let us code for the Functionality double Click on the button and the event handler is generated for the buttonclick before we start the code for the event let us include some namespaces:
      using System.Net.Mail; 
      using System.IO; 
      using System.Drawing;

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Here is the code for the button event. The code has inline commets to explain the meaning of each line.
using System;
using System.Drawing;
using System.IO;
using System.Net.Mail;
using System.Web;
 
namespace SendMailWithAttachment
{
 public partial class _Default : System.Web.UI.Page
  {
   protected void Page_Load(object sender, EventArgs e)
    {
    }
   protected void btnSend_Click(object sender, EventArgs e)
    {
     try
      {
       /* Create a new blank MailMessage with the FROM and TO addresses*/
       MailMessage mailMessage = new MailMessage(txtSender.Text,txtReceiver.Text);
       /* Checking the condition that the cc is empty or not.  
          If not then include them */
       if (txtCc.Text != null && txtCc.Text != string.Empty)
        {
         mailMessage.CC.Add(txtCc.Text);
        }
       /* Checking the condition that the Bcc is empty or not.  
          If not then include them */
       if (txtBcc.Text != null && txtBcc.Text != string.Empty)
        {
         mailMessage.Bcc.Add(txtBcc.Text);
        }
       //Adding Subject to the Mail
       mailMessage.Subject = txtSubject.Text;
       //Adding the Mail Body
       mailMessage.Body = txtBody.Text;
       /* Set the properties of the MailMessage to the values
          on the form as per the mail is HTML formatted or plain text */
       if (rblMailFormat.SelectedItem.Text == "Text")
         mailMessage.IsBodyHtml = false;
       else
         mailMessage.IsBodyHtml = true;
       /* We use the following variables to keep track of
          attachments and after we can delete them */
       string attach1 = null;
       string attach2 = null;
       string attach3 = null;
       /* strFileName has a attachment file name for 
          attachment process. */
       string strFileName = null;
       /* Begining of Attachment1 process & 
          check the first open file dialog for a attachment */
       if (inpAttachment1.PostedFile != null)
        {
         /* Get a reference to PostedFile object */
         HttpPostedFile attFile = inpAttachment1.PostedFile;
         /* Get size of the file */
         int attachFileLength = attFile.ContentLength;
         /* Make sure the size of the file is > 0 */
         if (attachFileLength > 0)
          {
           /* Get the file name */
           strFileName = Path.GetFileName(inpAttachment1.PostedFile.FileName);
           /* Save the file on the server */
           inpAttachment1.PostedFile.SaveAs(Server.MapPath(strFileName));
           /* Create the email attachment with the uploaded file */
           Attachment attach = new Attachment(Server.MapPath(strFileName));
           /* Attach the newly created email attachment */
           mailMessage.Attachments.Add(attach);
           /* Store the attach filename so we can delete it later */
           attach1 = strFileName;
          }
        }
       /* Attachment-2 Repeat previous step defiend above*/
       if (inpAttachment2.PostedFile != null)
        {
         HttpPostedFile attFile = inpAttachment2.PostedFile;
         int attachFileLength = attFile.ContentLength;
         if (attachFileLength > 0)
          {
           strFileName = Path.GetFileName(inpAttachment2.PostedFile.FileName);
           inpAttachment2.PostedFile.SaveAs(Server.MapPath(strFileName));
           Attachment attach = new Attachment(Server.MapPath(strFileName));
           mailMessage.Attachments.Add(attach);
           attach2 = strFileName;
          }
        }
       /* Attachment-3 Repeat previous steps step defined above */
       if (inpAttachment3.PostedFile != null)
        {
         HttpPostedFile attFile = inpAttachment3.PostedFile;
         int attachFileLength = attFile.ContentLength;
         if (attachFileLength > 0)
          {
           strFileName = Path.GetFileName(inpAttachment3.PostedFile.FileName);
           inpAttachment3.PostedFile.SaveAs(Server.MapPath(strFileName));
           Attachment attach = new Attachment(Server.MapPath(strFileName));
           mailMessage.Attachments.Add(attach);
           attach3 = strFileName;
          }
        }
       /* Set the SMTP server and send the email with attachment */
       SmtpClient smtpClient = new SmtpClient();
       // smtpClient.Host = emailServerInfo.MailServerIP;
       //this will be the host in case of gamil and it varies from the service provider
       smtpClient.Host = "smtp.gmail.com";
       //smtpClient.Port = Convert.ToInt32(emailServerInfo.MailServerPortNumber);
       //this will be the port in case of gamil for dotnet and it varies from the service provider
       smtpClient.Port = 587;
       smtpClient.UseDefaultCredentials = true;
       //smtpClient.Credentials = new System.Net.NetworkCredential(emailServerInfo.MailServerUserName, emailServerInfo.MailServerPassword);
       smtpClient.Credentials = new System.Net.NetworkCredential(txtUserName.Text, txtPassword.Text);
       //this will be the true in case of gamil and it varies from the service provider
       smtpClient.EnableSsl = true;
       smtpClient.Send(mailMessage); 
       /* Delete the attachements if any */
       try
        {
         if (attach1 != null)
           File.Delete(Server.MapPath(attach1));
         if (attach2 != null)
           File.Delete(Server.MapPath(attach2));
         if (attach3 != null)
           File.Delete(Server.MapPath(attach3));
        }
       catch{}
       /* clear the controls */
       txtSender.Text = string.Empty;
       txtReceiver.Text = string.Empty;
       txtCc.Text = string.Empty;
       txtBcc.Text = string.Empty;
       txtSubject.Text = string.Empty;
       txtBody.Text = string.Empty;
       txtUserName.Text = string.Empty;
       /* Dispaly a confirmation message to the user. */
       lblMessage.Visible = true;
       lblMessage.ForeColor = Color.Black;
       lblMessage.Text = "Message sent.";
      }
     catch (Exception ex)
      {
       /* Print a message informing the 
          user about the exception that was risen */
       lblMessage.Visible = true;
       lblMessage.ForeColor = Color.Red;
       lblMessage.Text = ex.ToString();
      }
    }
  }  // partial class _Default
}  // namespace SendMailWithAttachment

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Now You can debug the application; use F5 to launch the application fill the details like username of Gmail account and Password. The mail address to send the mails, the subject , the mail body and attach the files if necessary. Click on send button and the mail will be sent

Download code from here

Thanks and Regards

Meetu Choudhary

My Blog || My Web || My Forums
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