Send Email in C# - Example Codes

The following example codes demonstrate how to send email using SMTP/SSL/EWS/Queue, it also demonstrate how to sign email, encrypt email and add embedded images to email.

C#

• Send email using SMTP server - General
• Send email over SSL on 465 port
• Send email over TLS on 25 or 587 port
• Send email using Gmail SMTP server
• Send email using Yahoo SMTP server
• Send email using Hotmail, Outlook.com, Office 365
• Email Queue with EASendMail Service - General
• Email Queue with EASendMail Service - Database
• Send email using MX DNS lookup - smart host
• Request delivery receipt and read receipt - email trace
• Validate email address syntax and test email address
• DomainKeys and DKIM signature
• Send HTML email
• Send email with attachment
• Send HTML email with embedded images
• Sign email - S/MIME
• Encrypt email - S/MIME
• Send EML file
• Sign email (RSASSA-PSS + SHA256) and encrypt email (RSAES-OAEP + AES 128/196/256 + SHA256) based on EDIFACT rule - S/MIME
• Send email using Google/Gmail OAuth 2.0 authentication
• Send email using Gmail/G Suite OAuth 2.0 in background service (service account)
• Send email using Microsoft OAuth 2.0 (Modern Authentication) from Hotmail/Outlook account
• Send email using Microsoft OAuth 2.0 (Modern Authentication) + SMTP/EWS/Ms Graph API protocol from Office 365 account
• Send email using Microsoft OAuth 2.0 (Modern Authentication) + EWS/Ms Graph API protocol from Office 365 in background service