/// <summary>

/// 获取字符串的MD5值

/// </summary>

/// <param name="str">字符串</param>

/// <param name="salt">加盐值</param>

/// <returns></returns>

public static string MD5(this string str, string salt = "")

{

    //MD5计算类

    using (System.Security.Cryptography.MD5CryptoServiceProvider md5 = new System.Security.Cryptography.MD5CryptoServiceProvider())

    {

        byte[] bytValue, bytHash;

        //将要计算的字符串转换为字节数组

        bytValue = System.Text.Encoding.UTF8.GetBytes(salt + str);

        //计算结果同样是字节数组

        bytHash = md5.ComputeHash(bytValue);

        //将字节数组转换为字符串

        string sTemp = "";

        for (int i = 0; i < bytHash.Length; i++)

        {

            sTemp += bytHash[i].ToString("x").PadLeft(2, '0');

        }

        return sTemp;

    }

}