Why does the MailDefinition class require a System.Web.UI.Control?

Question

When creating a MailMessage object by calling the "CreateMailMessage" method on the MailDefinition class, the third parameter is an object of type System.Web.UI.Control.

MailDefinition mail = new MailDefinition();

ListDictionary replacements = new ListDictionary();
replacements.Add("<%myname%>", "John");

mail.BodyFileName = "~/App_Data/Emails/SomeEmail.txt";
mail.From = "[email protected]";
mail.Subject = "Hello";

MailMessage message = mail.CreateMailMessage("[email protected],", replacements, );

Why is that?
And in the case that I don't have an object of that type, what should I pass instead? Just a new Control object?

Control control = new Control();

UPDATE

I would highly recommend using Razor to build email templates. It has great syntax, works great, and doesn't have any weird dependencies!

Stew

Why aren't you using MailMessage message = new MailMessage()? – Photography

Answer 1

Usually you just pass this as the control.

MailMessage message = mail.CreateMailMessage("[email protected],", replacements, this);

As for the reason why, here is what MSDN says:

The owner parameter indicates which control is the parent of the MailDefinition control. It determines which directory to search for the text file specified in the BodyFileName property.

Minutiae

And what if I'm not running this from an ASPX page, but from an APP_CODE class? – Stew

Then you need to pass in a reference to the current control into the code that is creating the mail message. – Minutiae

Answer 2

The CreateMailMessage function internally uses the specified Control to query its AppRelativeTemplateSourceDirectory property and its OpenFile method to read the contents of the body (specified in the BodyFileName property of the MailDefinition).

Seems poor design and unnecessary tight coupling for me.

Harmonie

Indeed! But with the advent of the Razor templating engine, it doesn't really matter anymore :P razorengine.codeplex.com in case you've been living under a rock :) – Stew

@JohnBubriski Can I use RazorEngine in ASP.NET WebForms application ? – Giamo

Answer 3

You can also just do this:

MailMessage message = this.Mail.CreateMailMessage("[email protected]", dictionary, new System.Web.UI.Control());

Malloch

Answer 4

I have been using new LiteralControl() for the 3rd parameter because my messages are being sent from a Workflow. It works. But I do not have an answer for "Why".

Binion

Answer 5

It sounds like you may not need to use the MailDefinition class at all if you're not binding to any controls. To simply send an email over smtp, you should use a System.Net.Mail.SmtpClient with a System.Net.Mail.MailMessage.

Excitant

Basically, I'm using the MailDefinition class for its replacement abilities. – Stew

Razor engine IMO is the new best practice way. – Illustrator