using Microsoft.EntityFrameworkCore;

using Microsoft.Extensions.Options;

using System.ComponentModel.DataAnnotations;

namespace EFInstanceMethodTest

{

internal class Program

{

private class Executor

{

private string ImAnInstanceMethod(string? s) => s ?? "";

private static string ImAStaticMethod(string? s) => s ?? "";

public void DoInstanceThing()

{

using (var dx = new TestContext())

{

var result = dx.SOME_TABLE.Select(t => ImAnInstanceMethod(t.Field)).FirstOrDefault();

Console.WriteLine(result);

}

}

public void DoStaticThing()

{

using (var dx = new TestContext())

{

var result = dx.SOME_TABLE.Select(t => ImAStaticMethod(t.Field)).FirstOrDefault();

Console.WriteLine(result);

}

}

}

static void Main(string[] args)

{

var exe = new Executor();

Console.WriteLine("Calling a static method from final projection. Result:");

RunAndDump(exe.DoStaticThing);

Console.WriteLine("\r\nCalling an instance method from final projection. Result:");

RunAndDump(exe.DoInstanceThing);

}

private static void RunAndDump(Action a)

{

try

{

a();

}

catch (Exception ex)

{

Console.WriteLine(ex.ToString());

}

}

}

internal class TestContext : DbContext

{

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

{

optionsBuilder.UseSqlServer("<put your connection string here>", b => b.UseRelationalNulls(true));

}

protected override void OnModelCreating(ModelBuilder modelBuilder)

{

modelBuilder.HasDefaultSchema("testing");

modelBuilder.Entity<SOME_TABLE>().HasNoKey();

}

public virtual DbSet<SOME_TABLE> SOME_TABLE { get; set; }

}

internal class SOME_TABLE

{

[StringLength(25)]

[Unicode(false)]

public string? Field { get; set; }

}

}