Getting a null reference when when creating data in ASP.NET

Question

I'm trying to insert a customer in my database from the create page and I keep getting a null reference. My model is structured like like so:

Model

 public string Name { get; set; }
 ...
 public string FirstName { get { return Name.Substring(0, Name.IndexOf(" ")); } }
 public string LastName { get { return Name.Substring(Name.IndexOf(" ") + 1); } }

My controller is setup like so:

 [HttpPost]
 public ActionResult Create(Customer customer)
 {
      if (ModelState.IsValid)
      {
           Customer add = new Customer();

           add.Name = customer.FirstName + " " + customer.LastName;

           db.Customers.Add(add);
           db.SaveChanges();

I understand that when inserting data, the Name field will return a null because it doesn't have anything in the beginning. How should should I adjust this?

Is name guaranteed to be non-null? Looks to me that now you have as default value `Name == null`. — Willem Van Onsem, Jul 29 '18 at 20:18
Not all the time. I wrote my fields like that because they'll be loaded in the Index first. I'm having trouble when I get to the create page though — Alfie McNarutoad, Jul 29 '18 at 20:20
no, since here you write `customer.FirstName`, and this requires a `Name`. so your `Customer` probably has no set `Name` at that moment. — Willem Van Onsem, Jul 29 '18 at 20:21
yes exactly. FirstName and LastName isn't on the Table. Names are just in one "Name" column — Alfie McNarutoad, Jul 29 '18 at 20:24
As a side note, your FirstName and LastName wouldn't work if person has more than one word in his first name (ie: Alex de Souza, JFK, ...) — Cetin Basoz, Jul 29 '18 at 20:30
yes I agree. this is a project that I'm doing and they gave me a set with just one column for names — Alfie McNarutoad, Jul 29 '18 at 20:32

score 0 · Answer 1 · answered Jul 30 '18 at 00:44

Use a conditional to check if Name is empty. Use private fields to hold the first and last name records. Mark first and last name as NotMapped if they are not part of the table. NOTE: After setting Name the first time, you will need to edit the Name directly. You won't be able to change first and last name since you are checking if Name exists first.

private string firstName;
private string lastName;  

public string Name { get; set; }
[NotMapped]
public string FirstName { 
   get { return String.IsNullOrEmpty(Name) ? firstName : Name.Substring(0, Name.IndexOf(" ")); }
   set { firstName = value; }
}
[NotMapped]
public string LastName { 
   get { return String.IsNullOrEmpty(Name) ? lastName : Name.Substring(Name.IndexOf(" ") + 1 : );} 
   set { lastName = value; }
}

Getting a null reference when when creating data in ASP.NET

1 Answers1