>>The string will come from C++ application. Right now I want to simulate a test of such string.
>
>IIRC, a C++ string is a byte array. You could try:

string s = Convert.ToBase64String(cplusstring);

Yes, this doesn't work as the string is not really a byte array or something messed up with it.

In this thread I posted the exact string
https://social.msdn.microsoft.com/Forums/vstudio/en-US/8781a353-47be-435c-afa3-d69e41c18870/how-to-put-a-string-with-low-ascii-characters-as-a-string-into-c-code?forum=csharpgeneral