Correct Syntax For Generating Html Email Using Alternateview

I'm trying to use the AlternateView to cater for both HTML and Text clients. I would prefer to use HTML and only fall back to text where necessary. I started re-coding an old conso

Solution 1:

UPDATE - 09-30-2019: Microsoft updated the documentation for this.

As I guessed, I had to explicitly provide a plain text and HTML version of the message body. The MSDN documentation was not very helpful. Here's a snippet of the code I created to get this working:

// args[0] - Subject// args[1] - Plain text body content// args[2] - HTML body content// args[3] - RfpID

textMessage +="\n\nIf you no longer wish to receive notifications, you can "+"unsubscribe and your details will be removed from our system:\n"+"http://example.com/apps/vendorreg/unsubscribe.aspx?unsub="+ hash +"\n\n"+"Example Website Policies:\n"+"http://example.com/doc/help/policies/help_website_policies";

// Important: Mime standard dictates that text version must come first 
using (AlternateView textPart =AlternateView.CreateAlternateViewFromString(textMessage, null, "text/plain"))
{
    textPart.TransferEncoding=System.Net.Mime.TransferEncoding.QuotedPrintable;
    mailMessage.AlternateViews.Add(textPart);
    mailMessage.IsBodyHtml=false;
    mailMessage.Body= textMessage;
}

htmlMessage +=Environment.NewLine+Environment.NewLine+"If you no longer wish to receive notifications, you can "+"unsubscribe and your details will be removed from our system:"+Environment.NewLine+"http://example.com/apps/vendorreg/unsubscribe.aspx?unsub="+ hash
    +Environment.NewLine+Environment.NewLine+"Example.com Website Policies:"+Environment.NewLine+"http://example.com/doc/help/policies/help_website_policies";

using (AlternateView htmlPart =AlternateView.CreateAlternateViewFromString(htmlMessage,
    System.Text.Encoding.UTF8, "text/html"))
{
    htmlPart.TransferEncoding=System.Net.Mime.TransferEncoding.QuotedPrintable;
    mailMessage.AlternateViews.Add(htmlPart);
    mailMessage.IsBodyHtml=true;
    mailMessage.Body= htmlMessage;
}

// Send email