C# 生成自定义长度的0-z随机字符串

C# 生成自定义长度的0-z随机字符串：

private static char[] constant = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' };
/// <summary>
/// 生成0-z的随机字符串
/// </summary>
/// <param name="length">字符串长度</param>
/// <returns>随机字符串</returns>
public static string GenerateRandomString(int length)
{
    string checkCode = String.Empty;
    Random rd = new Random();
    for (int i = 0; i < length; i++)
    {
        checkCode += constant[rd.Next(36)].ToString();
    }
    return checkCode;
}