Problem with converting SQL to LINQ code

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Hi!

I have sql code that returns all appointment times that are not used on certain date

SQL

select terminRez
from TerminRezervacije t
where not exists(select TerminRezervacijeID
from Rezervacija as r where
t.TerminRezervacijeID=r.TerminRezervacijeID and  r.DatumRezervacije= '2021-01-14')

I managed to recreate it as query with c# LINQ

C#

var termin = from t in db.TerminRezervacije
                        where !db.Rezervacija.Where(r => t.TerminRezervacijeID == r.TerminRezervacijeID
                        && r.DatumRezervacije == mod.DatumRezervacije).Any()
                        select  t.terminRez;

I want to be able to display available appointment times with dropdown list.
Right now i have setup with SelectListItem that loads all appointment times from db
and cant figure out how to implement this linq query to be able to display results of query in my SelectListItem dropdown list.

C#

model.TerminRezervacije = db.TerminRezervacije
            .Select(p => new SelectListItem
            {
                Value = p.TerminRezervacijeID.ToString(),
                Text = p.terminRez


            }).ToList();

I appreciate any help!!

What I have tried:

I recreated sql query in linq code but cant figure out how to add query results to dropdown list

Posted 15-Jan-21 15:30pm

sasko1

Updated 15-Jan-21 23:41pm

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Maciej Los · Accepted Answer · 2021-01-15T23:41:00

Your query can be re-written this way:

C#

var termin = db.TerminRezervacije
    .Where(t=>  
        !db.Rezervacija.Any(r => t.TerminRezervacijeID == r.TerminRezervacijeID
            && r.DatumRezervacije == mod.DatumRezervacije))
    //.Select(t=> t)
    .ToList();

Then you need to bind the result of above query to DropDownList. For further details, please see:
Populate (Bind) DropDownList from ViewModel in ASP.Net MVC[^]
Create DropDownList using HtmlHelper in ASP.Net MVC[^]
Using the DropDownList Helper with ASP.NET MVC | Microsoft Docs[^]