I have a C# web app that sends out mails but I ran into an issue with email subject lengths. In Outlook and Firebird a tab is inserted at about every 78 characters. After googling this is what I found:
"Each header field is logically a single line of characters comprising the field name, the colon, and the field body. For convenience however, and to deal with the 998/78 character limitations per line, the field body portion of a header field can be split into a multiple-line representation; this is called "folding". The general rule is that wherever this specification allows for folding white space (not simply WSP characters), a CRLF may be inserted before any WSP.
For example, the header field:
Subject: This is a test
can be represented as: Subject: This
is a test
Note: Though structured field bodies are defined in such a way that folding can take place between many of the lexical tokens (and even within some of the lexical tokens), folding SHOULD be limited to placing the CRLF at higher-level syntactic breaks. For instance, if a field body is defined as comma-separated values, it is recommended that folding occur after the comma separating the structured items in preference to other places where the field could be folded, even if it is allowed elsewhere.
The process of moving from this folded multiple-line representation of a header field to its single line representation is called "unfolding". Unfolding is accomplished by simply removing any CRLF that is immediately followed by WSP. Each header field should be treated in its unfolded form for further syntactic and semantic evaluation. An unfolded header field has no length restriction and therefore may be indeterminately long."
RFC 5322
I tried inserting "\n", "\r", Environment.NewLine and "\r\n" in the subject before the last white space before every 78 character with no success. How do I get the subject to "fold" when its length exceeds 78 characters?