What does LINQ return when the result is null in C#?

Language Integrated Query (LINQ) is a set of Integrate query capabilities directly into the C# language.

You can use C# to create SQL Server databases, XML documents, ADO.NET data sets, and any collection of objects that support IEnumerable or generic IEnumerableinterface.

In Linq-to-SQL, if you try to get the first element in a query that has no results, you will The obtained sequence does not contain any elements Error

ToList returns an empty list

Example

class Program{
   public static void Main(){
      List<string> list = new List<string> { "a" };
      IEnumerable<string> ilist = list.Where(x => x == "ABC").ToList();
      System.Console.WriteLine(ilist.Count());
      foreach (var item in ilist){
         System.Console.WriteLine(item);
      }
      Console.ReadLine();
   }
}

Output

0

Example

The Chinese translation is:

Example

class Program{
   public static void Main(){
      List<int> list = new List<int> { 1 };
      IEnumerable<int> ilist = list.Where(x => x == 3).ToList();
      System.Console.WriteLine(ilist.Count());
      foreach (var item in ilist){
         System.Console.WriteLine(item);
      }
      Console.ReadLine();
   }
}

Output

0

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