How do I replace the *first instance* of a string in .NET?

Question

I want to replace the first occurrence in a given string.

How can I accomplish this in .NET?

Answer 1

string abc = "AAAAX1";

            if(abc.IndexOf("AA") == 0)
            {
                abc.Remove(0, 2);
                abc = "XQ" + abc;
            }