Question

I searched SO and found some posts, but could not get them to work.

Question: How would I loop to the next item in my List Collection (custLoginHist[1] etc)?

    List<eCommCustomer.oCustomer> custLoginHist = new List<eComm.oCustomer>();
    eCommCustomerDAL.GetCustomerPrevLogin(custLoginHist, oCust);

    if (custLoginHist.Count > 0)
    {
        eCommSecurityFactory oSecFactory = new eCommSecurityFactory();
        if (oCust.CustHash == oSecFactory.CreateHash(custLoginHist[0].CustSalt, custLoginHist[0].CustHash))
        {
            //Password has been used before;
            return false;
        }
        else
        {
            // Valid password;
            return true;
        }
    }
    return true;
}

Answer 1

foreach(eCommCustomer.oCustomer cust in custLoginHist)
{
  //Do something with cust here.
}

OR:

for(int i = 0; i != custLoginHist.Count; ++i)
{
  eCommCustomer.oCustomer cust = custLoginHist[i];
  //Do something with cust here.
}

In this case, we want to return false for any single match, and true otherwise, so:

foreach(eCommCustomer.oCustomer cust in custLoginHist)
  if(oCust.CustHash == oSecFactory.CreateHash(custLoginHist[0].CustSalt, custLoginHist[0].CustHash)
    return false;
return true;//if we reached here, no matches.

This is a bad idea though, because you’ve made breaking into the system easier. If I try to set my password to something, and you refuse, I now know that one of your users uses that password. You are much better off letting this case happen, though you should perhaps be blocking some of the more likely offenders (“password”, “password1”, etc) with a quality check.