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

This example abstracts away the substrings (but is slower), but is probably much fast than a RegEx:

var parts = contents.ToString().Split(new string[] { "needle" }, 2, StringSplitOptions.None);
return parts[0] + "replacement" + parts[1];