Question

今天,在StackOverflow的帮助下,我把我的数据层从我的XML档案中修建了返回数据。然而,我似乎从我的商业目标层面获得数据。这些价值观完全无效。 Sorry, to be such a newbie... 提前感谢。

3. 商业逻辑层面:

public void getCustDetails(string customerId)
{                          
    DLGetCustomers obj = new DLGetCustomers();
    obj.getCustDetails(customerId);
    AccountDetails obj1 = new AccountDetails();
    FirstName = obj1.Fname;
    LastName = obj1.Lname;
    SSN = obj1.Ssn;
    Dob = Convert.ToDateTime(obj1.Dob);
    CustomerId = Convert.ToInt32(obj1.Custid);
    TimeSpan ts = DateTime.Now - Convert.ToDateTime(Dob);
    Age = ts.Days / 365;
}

数据存取层:

public class AccountDetails
{
    public string Fname { get; set; }
    public string Lname { get; set; }
    public string Ssn { get; set; }
    public string Dob { get; set; }
    public string Custid { get; set; }
} 

public IEnumerable<AccountDetails> getCustDetails(string customerId)
{
    //Pulls customer information for selected customer 
    var doc = XDocument.Load("Portfolio.xml");
    var custRecords = from account in doc.Descendants("acct")
                      let acct = account.Element("acct")
                      where (string)account.Attribute("custid").Value == customerId
                      select new AccountDetails
                      {
                          Fname = (string)account.Attribute("fname").Value,
                          Lname = (string)account.Attribute("lname").Value,
                          Ssn = (string)account.Attribute("ssn").Value,
                          Dob = (string)account.Attribute("dob").Value,
                          Custid = (string)account.Attribute("custid").Value
                      };                          

    return custRecords;
}

Answer 1

本条:

AccountDetails obj1 = new AccountDetails();

缩略语:obj1至的新例:AccountDetails,该新例将满载空示。

You probably need to change getCustDetails in your DAL to return an instance of AccountDetails instead of an IEnumerable of it, and set obj1 to that:

AccountDetails obj1 = obj.getCustDetails(customerId);

阁下:

public AccountDetails getCustDetails(string customerId)
{
    //Pulls customer information for selected customer 
    var doc = XDocument.Load("Portfolio.xml");
    var custRecords = from account in doc.Descendants("acct")
                      let acct = account.Element("acct")
                      where (string)account.Attribute("custid").Value == customerId
                      select new AccountDetails
                      {
                          Fname = (string)account.Attribute("fname").Value,
                          Lname = (string)account.Attribute("lname").Value,
                          Ssn = (string)account.Attribute("ssn").Value,
                          Dob = (string)account.Attribute("dob").Value,
                          Custid = (string)account.Attribute("custid").Value
                      };


    return custRecords.FirstOrDefault();
}

Note that if your DAL can t find an account with the specified customerId, it will return a null (which is the default value of a class). You will need to check the return value against null before using if you do not want a NullReferenceException to be thrown in such an eventuality.

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