In this article I will explain with an example, how to send email with multiple attachments in ASP.Net Core Razor Pages.
Mail Server Settings in AppSettings.json file
The mail server settings are saved in the Smtp section as shown below.
{
"Smtp": {
"Server": "smtp.gmail.com",
"Port": 587,
"EnableScl": true,
"DefaultCredentials": true
}
}
Model
The Model class consists of the following properties.
Note: IFormFile is the new Class for Files in .Net Core. It is a replacement of HttpPostedFileBase class.
public class EmailModel
{
public string To { get; set; }
public string Subject { get; set; }
public string Body { get; set; }
public List<IFormFile> Attachments { get; set; }
public string Email { get; set; }
public string Password { get; set; }
}
Namespaces
You will need to import the following namespaces.
using System.IO;
using System.Net;
using System.Net.Mail;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
Razor PageModel (Code-Behind)
The Controller consists of following Handler methods.
Handler method for handling GET operation
This Handler method left empty as it is not required.
Handler method for handling POST operation
This Handler method handles the call made from the POST function from the View.
MailMessage Class Properties
Following are the required properties of the MailMessage class.
From – Sender’s email address.
To – Recipient(s) Email Address.
CC – Carbon Copies. (If any)
BCC – Blind Carbon Copies. (If any)
Subject – Subject of the Email.
Body – Body of the Email.
Attachments – Attachments. (If any)
ReplyTo – ReplyTo Email address.
SmptClient Class Properties
Following are the properties of the SmtpClient class.
Host – SMTP Server URL (Gmail: smtp.gmail.com).
EnableSsl – Specify whether your host accepts SSL Connections (Gmail: True).
UseDefaultCredentials – Set to True in order to allow authentication based on the Credentials of the Account used to send emails.
Credentials – Valid login credentials for the SMTP server (Gmail: email address and password).
Port – Port Number of the SMTP server (Gmail: 587)
When Send button is clicked, the posted values from their respective fields are captured through the EmailModel class object and are set into an object of the MimeMessage class.
And if the IFormFile has attachments then, a FOR EACH loop is executed over the IFormFile and all the selected files are added as Attachment to the list of Attachments of the MailMessage class object.
Then, object of the SmtpClient class is created and the settings of the Mail Server such has Host, Port, EnableSsl and DefaultCredentials are fetched from the Smtp section of the AppSettings.json file.
Finally, the email is sent using Send method of SmtpClient and success message is set to the ViewData object.
public class IndexModel : PageModel
{
public EmailModel Model { get; set; }
public IConfiguration Configuration { get; set; }
public IndexModel(IConfiguration _configuration)
{
this.Configuration = _configuration;
}
public void OnGet()
{
}
public void OnPostSendEmail(EmailModel model)
{
string host = this.Configuration.GetValue<string>("Smtp:Server");
int port = this.Configuration.GetValue<int>("Smtp:Port");
bool enableSsl = this.Configuration.GetValue<bool>("Smtp:EnableSsl ");
bool defaultCredentials = this.Configuration.GetValue<bool>("Smtp:DefaultCredentials");
using (MailMessage mm = new MailMessage(model.Email, model.To))
{
mm.Subject = model.Subject;
mm.Body = model.Body;
if (model.Attachments != null)
{
foreach (IFormFile attachment in model.Attachments)
{
string fileName = Path.GetFileName(attachment.FileName);
mm.Attachments.Add(new Attachment(attachment.OpenReadStream(), fileName));
}
}
mm.IsBodyHtml = false;
using (SmtpClient smtp = new SmtpClient())
{
smtp.Host = host;
smtp.EnableSsl = enableSsl;
NetworkCredential networkCred = new NetworkCredential(model.Email, model.Password);
smtp.UseDefaultCredentials = defaultCredentials;
smtp.Credentials = networkCred;
smtp.Port = port;
smtp.Send(mm);
}
}
ViewData["Message"] = "Email sent.";
}
}
Razor Page (HTML)
Inside the Razor Page, the EmailModel class is declared as model for the View and ASP.Net TagHelpers in inherited.
The HTML of Razor Page consists of an HTML Form.
The HTML Form has been specified with enctype=“multipart/form-data” attribute as it is necessary for File Upload operation
Inside the Form there is an HTML Table which consists of some INPUT TextBoxes, in which one TextBox type is set to file.
The Table also consists of an INPUT TextArea and a Submit button.
The Submit Button has been set with the POST Handler method using the asp-page-handler attribute.
Note: In the Razor PageModel, the Handler method name is OnPostSubmit but here it will be specified as Submit when calling from the Razor HTML Page.
When the Send Button is clicked, the Form gets submitted and the Model object is sent to the PageModel.
@page
@model Send_Email_Attachments_Core_Razor.Pages.IndexModel
@addTagHelper*, Microsoft.AspNetCore.Mvc.TagHelpers
@{
Layout = null;
}
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>Index</title>
</head>
<body>
<form method="post" enctype="multipart/form-data">
<table>
<tr>
<td style="width: 80px">To:</td>
<td><input type="text" asp-for="Model.To" /></td>
</tr>
<tr><td> </td></tr>
<tr>
<td>Subject:</td>
<td><input type="text" asp-for="Model.Subject" /></td>
</tr>
<tr><td> </td></tr>
<tr>
<td valign="top">Body:</td>
<td><textarea cols="20" rows="3" asp-for="Model.Body"></textarea></td>
</tr>
<tr><td> </td></tr>
<tr>
<td>File Attachment:</td>
<td><input type="file" asp-for="Model.Attachments" multiple="multiple" /></td>
</tr>
<tr><td> </td></tr>
<tr>
<td>Gmail Email:</td>
<td><input type="text" asp-for="Model.Email" /></td>
</tr>
<tr><td> </td></tr>
<tr>
<td>Gmail Password:</td>
<td><input type="password" asp-for="Model.Password" /></td>
</tr>
<tr><td> </td></tr>
<tr>
<td></td>
<td><input type="submit" value="Send" asp-page-handler="SendEmail" /></td>
</tr>
</table>
</form>
@if (ViewData["Message"] != null)
{
<script type="text/javascript">
window.onload = function () {
alert("@ViewData["Message"]");
};
</script>
}
</body>
</html>
Possible Errors
The following error occurs when you try to send email using Gmail credentials in your application.
The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at
Solution
Screenshot
Email Form
![ASP.Net Core Razor Pages: Send Email with Multiple Attachments]()
Received Email
![ASP.Net Core Razor Pages: Send Email with Multiple Attachments]()
Downloads
