If there is no result, I want an error message to appear, but I could not do it. Any ideas?

otomobil.Add(new Markalar { Marka = "Skoda", Model = "Fabia" });
otomobil.Add(new Markalar { Marka = "Opel", Model = "Astra" });
otomobil.Add(new Markalar { Marka = "Opel", Model = "Vectra" });
otomobil.Add(new Markalar { Marka = "Skoda", Model = "Octavia" });
otomobil.Add(new Markalar { Marka = "BMW", Model = "i5" });
otomobil.Add(new Markalar { Marka = "Audi", Model = "A8" });

Console.WriteLine("Type the brand you want to search:");

string otomarka = Console.ReadLine();

var araba = otomobil.Where(p => p.Marka == otomarka);

foreach (var arac in araba)
{
    Console.WriteLine(arac.Model);

    if (arac == null)
        Console.WriteLine("There were no results");
}

CodePudding user response：

Well, you should check if query's result is empty; we can do it with a help of .DefaultIfEmpty():

var araba = otomobil
  .Where(p => p.Marka == otomarka)
  .DefaultIfEmpty(); // single null if Where returns empty enumerable

foreach (var arac in araba) {
  // if we have null, then we have no result
  if (arac == null) {
    Console.WriteLine("There were no results");

    break;
  }

  Console.WriteLine(arac.Model);
}