In verbatim string literals (@"...") a " in the string value is encoded as "", which happens to also be the only escape sequence in verbatim strings.
@"\""Happy coding!\""" // => \"Happy coding!\"
"\\\"Happy coding!\\\"" // => \"Happy coding!\"
Note that in the 2nd case (not a verbatim string literal), a \ is required before the \ and the " to escape them and prevent their normal meanings.
See the C# string reference for more details and examples.
单纯的字符串的话,直接加\进行转义。但是在@开头的字符串中,使用""来表示"