You don’t need that. Anything within an attribute value is character data.
Since you’re reading these values using C#, they’ll get escaped as if they would be a literal path string in code.
Anyway, you might want to know that C# has @ operator to declare verbatim strings, meaning that you don’t need to escape backslashes when using literal paths in code:
string somePath = @"C:\blah\blih\bluh.txt";