how to merge or inject "@" character in a string including escape characters without definning the string varibale from scratch in C#

Answer 1

No, because the compiler has already converted all of your escaped characters in the original string to the characters they represent. After the fact, it is too late to convert them to non-special characters. You can do a search and replace, converting '\n' to literally @"\n", but that is whacky and you're better off defining the string correctly in the first place. If you wanted to escape the backslashes in the first place, why not put an extra backslash character in front of each of them:

Instead of "\n" use "\\n".

Updated in response to your comment:

If the string is coming from user input, you don't need to escape the backslash, because it will be stored as a backslash in the input string. The escape character only works as an escape character in string literals in code (and not preceded by @, which makes them verbatim string literals).

Answer 2

if you want "\n\n\a\a\r\blah" to print as \n\n\a\a\r\blah without @ just replace all \ with \\

\ is the escaper in a non-verbatim string. So you simply need to escape the escaper, as it were.

Answer 3

If you want to use both strings, but want to have only one in the code then write the string with @, and construct the other one with Replace(@"\n","\n").