一个根据字母，数字和符号组合生成指定长度密码的简单方法

　　前言：网上没有太好的直接可用的方法，于是自己写了一个，下面的方法可以根据字母，数字和符号组合生成指定长度密码，策略和长度可控，详细代码如下：

/// <summary>
/// 生成密码
/// </summary>
/// <param name="zmLength">小写字母长度</param>
/// <param name="upzmLength">大写字母长度</param>
/// <param name="szLength">数字长度</param>
/// <param name="zfLength">字符长度</param>
/// <returns></returns>
public static string BuildNewPwd(int zmLength, int upzmLength, int szLength, int zfLength)
{
    char[] zmArray = new char[] { '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' };
    char[] upzmArray = new char[] { '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' };
    char[] szArray = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
    char[] zfArray = new char[] { '%', '_', '.' };

    Random random = new Random();
    string pwd = "";

    Action<int, char[]> updatePwdAction = (insertCount, dataArray) =>
    {
        for (int i = 0; i < insertCount; i++)
        {
            int dataIndex = random.Next(0, dataArray.Length);
            char data = dataArray[dataIndex];
            int insertIndex = random.Next(0, (pwd.Length == 0 ? 1 : pwd.Length));
            pwd = pwd.Insert(insertIndex, data.ToString());
        }
    };

    updatePwdAction(zmLength, zmArray);
    updatePwdAction(upzmLength, upzmArray);
    updatePwdAction(szLength, szArray);
    updatePwdAction(zfLength, zfArray);

    return pwd;
}