C#. How to remove the part of a string that comes after the last character, such as a comma?

Question

C++ / C#

Yes:
string aaa = "Hi, what are you doing, how are you";
Needed:
string aaa = "Hi, what are you doing";
string bbb = "how are you";

Answer 1

string aaa = "Привет, что делаешь, как дела";
int pos = aaa.LastIndexOf(',');
string bbb = aaa.Substring(pos);
aaa = aaa.Substring(0, pos);

Answer 2

string aaa = "Привет, что делаешь";
string bbb = aaa.Split(',').Last();

Answer 3

remove the part of the string that comes after the last character

aaa = aaa.Substring(0, aaa.LastIndexOf(',') + 1);