c# 生成指定长度的唯一标识方法

public static string GetUniqueIdentifier(int length)
{
int maxSize = length;
char[] chars = new char[62];
string a;
a = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
chars = a.ToCharArray();
int size = maxSize;
byte[] data = new byte[1];
var crypto = new RNGCryptoServiceProvider();
crypto.GetNonZeroBytes(data);
size = maxSize;
data = new byte[size];
crypto.GetNonZeroBytes(data);
var result = new StringBuilder(size);
foreach (byte b in data)
{
result.Append(chars[b % (chars.Length - 1)]);
}
// Unique identifiers cannot begin with 0-9
if (result[0] >= '0' && result[0] <= '9')
{
return GetUniqueIdentifier(length);
}
return result.ToString();
}