How to convert UTF-8 byte[] to string?

Question

I have a byte[] array that is loaded from a file that I happen to known contains UTF-8.

In some debugging code, I need to convert it to a string. Is

Answer 1

To my knowledge none of the given answers guarantee correct behavior with null termination. Until someone shows me differently I wrote my own static class for handling this with the following methods:

// Mimics the functionality of strlen() in c/c++
// Needed because niether StringBuilder or Encoding.*.GetString() handle \0 well
static int StringLength(byte[] buffer, int startIndex = 0)
{
    int strlen = 0;
    while
    (
        (startIndex + strlen + 1) < buffer.Length // Make sure incrementing won't break any bounds
        && buffer[startIndex + strlen] != 0       // The typical null terimation check
    )
    {
        ++strlen;
    }
    return strlen;
}

// This is messy, but I haven't found a built-in way in c# that guarentees null termination
public static string ParseBytes(byte[] buffer, out int strlen, int startIndex = 0)
{
    strlen = StringLength(buffer, startIndex);
    byte[] c_str = new byte[strlen];
    Array.Copy(buffer, startIndex, c_str, 0, strlen);
    return Encoding.UTF8.GetString(c_str);
}

The reason for the startIndex was in the example I was working on specifically I needed to parse a byte[] as an array of null terminated strings. It can be safely ignored in the simple case