Create controller "Object reference not set to an instance of an object"

Question

I have a create controller on ASP Net core application, that creates a new FinancePaymentReceipt.

The controller

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create([Bind("FinanceInvoiceID,Payment_Reference_Number,FinancePaymentTypeID,Payment_Amount,Payment_Date")]  FinancePaymentReceipt financePaymentReceipt)
{
    var invoice = await _context.FinanceInvoices
                                .Include(fi=>fi.FinanceDailyClaim)
                                            .ThenInclude(fdc=>fdc.Department)
                                               .Where(ss=>ss.FinanceInvoiceID==financePaymentReceipt.FinanceInvoiceID)
                                                .SingleOrDefaultAsync();

   if (invoice == null)
   {
       return NotFound();
   }

   if (ModelState.IsValid)
    {
       financePaymentReceipt.PaymentReceiptNumber = await _numberSequence.GetNumberSequence("RECPT", invoice.FinanceDailyClaim.Department.Department_Code, 'C');

        _context.Add(financePaymentReceipt);

        await _context.AddAsync(new FinanceAccountSatement
        {
           FinancePaymentReceiptID = financePaymentReceipt.FinancePaymentReceiptID,
           Activity_Date = financePaymentReceipt.Date_Captured
         });

         await _context.SaveChangesAsync();

         return RedirectToAction(nameof(Index));
}

The model

public class FinancePaymentReceipt
{
   private decimal _Payment_Amount;

   [Key]
   public int FinancePaymentReceiptID { get; set; }

   [Display(Name = "Payment Receive Number")]
   public string PaymentReceiptNumber { get; set; }

   [Display(Name = "Invoice Number")]
   public int FinanceInvoiceID { get; set; }

   [Display(Name = "Payment Reference No")]
   public string Payment_Reference_Number { get; set; }

   [Display(Name = "Payment Type")]
   public int FinancePaymentTypeID { get; set; }

   public decimal Payment_Amount
   {
      get { return _Payment_Amount; }
      set
          {
                _Payment_Amount = -Math.Abs(value);
           }
        }

     public string Description
     {
        get
        {
                return $"Payment for {FinanceInvoice.Invoice_Number} Thank You";
        }
      }
      public DateTime Payment_Date { get; set; }

      public string Captured_By { get; set; }

      public DateTime Date_Captured { get; set; } = DateTime.Now;

      public FinanceInvoice FinanceInvoice { get; set; }

      public FinancePaymentType FinancePaymentType { get; set; }
}

From the FinancePaymentReceipt model above i have a property Description and it has only the get accesor and retrieves the Invoice number from the FinanceInvoice model.

But the problem is that when i create it, tries to get the Description before saving the model to the database, In fact if I put a break point before at the start of the create controller it does not even hit.

i just get the error Object reference not set to an instance of an object when i click the 'create button`

Is there a way around this issue?

Try adding `[NotMapped]` to the properties not in the database. https://www.entityframeworktutorial.net/code-first/notmapped-dataannotations-attribute-in-code-first.aspx — Steve Greene, Jul 23 '19 at 18:32

score 0 · Answer 1 · answered Jul 23 '19 at 16:57

One solution is just to return null for the Description if FinanceInvoice hasn't been set yet. Something like this:

 public string Description
 {
    get
    {
            return FinanceInvoice == null
                       ? null
                       : $"Payment for {FinanceInvoice.Invoice_Number} Thank You";
    }
  }

I'm using C#'s conditional operater there.

Create controller "Object reference not set to an instance of an object"

1 Answers1