received error CS1061 with DateTime?

Question

Hi,

I've a class model : public DateTime DateSolde { get; set; } ;

I would like to transform this class model by ; public DateTime? DateSolde { get; set; } ;

I've also IActionResult in controller.

     public IActionResult MonthlyStats()  
        {  
             int numberecr = context.Developers.Count();  
            int calculN = context.Developers.Count(number => number.DateSolde > number.DateSoldePr && number.Statut == "Close");  
            int open = context.Developers.Count(a => a.DateCrea.Month == DateTime.Today.Month);  
            int close = context.Developers.Count(a => a.DateSolde.Month == DateTime.Today.Month && a.DateSolde.Year == _currentYear);  
  
            double data = Math.Round(((double)calculN) / numberecr, 1);  
  
            var stats = new  
            {  
                NombreECR = calculN,  
                Ratio = data,  
                EcrTotal = numberecr,  
                OpenECR = open,  
                CloseECR = close  
            };  
            return Ok(JsonSerializer.Serialize(stats, new JsonSerializerOptions   
            {   
                PropertyNamingPolicy = null  
            }));  
             
        }  

But when I put DateTime? I received the message

DateTime?' does not contain a definition for 'Year' and no accessible 'Year' extension method accepting a first argument of type 'DateTime?' was found (is a using directive or >assembly reference missing?) WebApp3.Server

It's same things for month.

Why I received this message?

I need to put DateTime? because I use DatePicker and it's necessary to have it.
thanks in advance to your answer

Answer 1

The nullable types do not have a Year or Month member. You must get the value of the nullable type first. Please read the official documentation.

Example code.

[HttpGet("TestDateSolde")]  
public async Task<IActionResult> TestDateSolde()  
{  
    int _currentYear = 2022;  
    int close = await _context.Developers.CountAsync(a =>   
        (a.DateSolde.HasValue && a.DateSolde.Value.Month == DateTime.Today.Month) &&   
        (a.DateSolde.HasValue && a.DateSolde.Value.Year == _currentYear));  
  
    return Ok(close);  
}  

Please do not mindlessly copy and paste the sample code like you did above. Make an effort to learn C# syntax.

Answer 2

 public DateTime? DateSolde { get; set; }  


int close = context.Developers.Count(a => (a.DateSolde.HasValue && a.DateSolde.Value.Month == DateTime.Today.Month) && (a.DateSolde.HasValue && a.DateSolde.Value.Year == _currentYear));  

It's OK thanks to everyone!