This culd be usefui, if a string is null or it has spaces at the end;

Example:

string Test = "1, 2, 3, 4,  ";

Test = Test.TrimEnd(',');
//Result: "1, 2, 3, 4,  ";

Test = (Test ?? "").Trim().TrimEnd(',');
//Result: "1, 2, 3, 4";