var chars = "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();
var buffer = new StringBuilder();
var rnd = new Random();
int count = 17;
for (int i = 0; i < count; i++)
{
buffer.Append(chars[rnd.Next(chars.Length)]);
}
return buffer.ToString();