add 0 before number if < 10

Question

This is my code:

string Unreadz = "0";
while (true)
{
    Unreadz = CheckMail();       
    if (!Unreadz.Equals("0")) port.Write("m");
    else port.Write("n");
}

If Unreadz is less than 10, I want to add a 0 before it, before port.write.

This is what I have tried:

if (Unreadz < 10) port.Write("0" + Unreadz);
else port.Write("" + Unreadz);

but it doesn't work because Unreadz is a string.

Answer 1

This should work:

port.Write(Unreadz.ToString().PadLeft(2, '0'));