也来个c#随机生成字符串

class gloser
{
Random m_rnd = new Random();
public char getRandomChar()
{
int ret = m_rnd.Next(122);
while (ret < 48 || (ret > 57 && ret < 65) || (ret > 90 && ret < 97))
{
ret = m_rnd.Next(122);
}
return (char)ret;
}
public string getRandomString(int length)
{
StringBuilder sb = new StringBuilder(length);
for (int i = 0; i < length; i++)
{
sb.Append(getRandomChar());
}
return sb.ToString();
}
}