C# regex fails to split string by pipe delimiter

Question

string query = "A|B";

The output of the next 2 lines are equal to "%A%|%B%" whereas "A%B" is expected!

query = Regex.Replace(query, "|", "%");
query = Regex.Replace(query, @"|", "%");

Why?

Answer 1

The | is a special character of regexes, it means "or". You have to escape it.

query = Regex.Replace(query, @"\|", "%");