HasConversion to a nullable Type does not seem to work

[YanicHoegger]

Hello

I would like to change a property of double into a double? column. My idea of doing so would be through a converter. But when I run the dotnet ef Migrations add command it still creates a column with nullable: false. How can I make a nullable column through the fluent api? I also tried to set IsRequired(false) but that throws an exception.

Here is the DataContext i was trying:

namespace EfCoreNaN;

public class MyContext : DbContext
{
    public DbSet<Entity> Entities { get; set; }
    
    protected sealed override void OnConfiguring(DbContextOptionsBuilder options)
    {
        options.UseSqlServer("Server=(localdb)\\test;Database=Test;Trusted_Connection=True;MultipleActiveResultSets=true");
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        
        var valueConverter = new ValueConverter<double, double?>(x => ConvertToProvider(x), x => ConvertFromProvider(x));
        modelBuilder.Entity("EfCoreNaN.Entity")
            .Property(nameof(Entity.NullableValue))
            .HasConversion(valueConverter);

        modelBuilder.Entity("EfCoreNaN.Entity")
            .Property(nameof(Entity.StringValue))
            .HasConversion(new ValueConverter<double, string>(x => x.ToString(CultureInfo.InvariantCulture), x => double.Parse(x)));
    }

    private double ConvertFromProvider(double? value)
    {
        return value ?? double.NaN;
    }

    private static double? ConvertToProvider(double value)
    {
        return double.IsNaN(value) ? null : value;
    }
}

public class Entity
{
    [Key]
    public int Id { get; set; }
    public double NullableValue { get; set; }
    public double StringValue { get; set; }
}

And that is the generated code:

migrationBuilder.CreateTable(
                name: "Entities",
                columns: table => new
                {
                    Id = table.Column<int>(type: "int", nullable: false)
                        .Annotation("SqlServer:Identity", "1, 1"),
                    NullableValue = table.Column<double>(type: "float", nullable: false),
                    StringValue = table.Column<string>(type: "nvarchar(max)", nullable: false)
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_Entities", x => x.Id);
                });

EF Core version: 8.0.4
Database provider: Microsoft.EntityFrameworkCore.SqlServer
Target framework: .NET 8.0
Operating system: W10
IDE: Visual Studio 2022 17.8.6 & JetBrains Rider 2024.1.1

Solution as .zip

[ajcvickers]

Duplicate of #13850. See also #24685.

[alandryz83]

Hello

I would like to change a property of double into a double? column. My idea of doing so would be through a converter. But when I run the dotnet ef Migrations add command it still creates a column with nullable: false. How can I make a nullable column through the fluent api? I also tried to set IsRequired(false) but that throws an exception.

Here is the DataContext i was trying:

namespace EfCoreNaN;



public class MyContext : DbContext

{

    public DbSet<Entity> Entities { get; set; }

    

    protected sealed override void OnConfiguring(DbContextOptionsBuilder options)

    {

        options.UseSqlServer("Server=(localdb)\\test;Database=Test;Trusted_Connection=True;MultipleActiveResultSets=true");

    }



    protected override void OnModelCreating(ModelBuilder modelBuilder)

    {

        base.OnModelCreating(modelBuilder);

        

        var valueConverter = new ValueConverter<double, double?>(x => ConvertToProvider(x), x => ConvertFromProvider(x));

        modelBuilder.Entity("EfCoreNaN.Entity")

            .Property(nameof(Entity.NullableValue))

            .HasConversion(valueConverter);



        modelBuilder.Entity("EfCoreNaN.Entity")

            .Property(nameof(Entity.StringValue))

            .HasConversion(new ValueConverter<double, string>(x => x.ToString(CultureInfo.InvariantCulture), x => double.Parse(x)));

    }



    private double ConvertFromProvider(double? value)

    {

        return value ?? double.NaN;

    }



    private static double? ConvertToProvider(double value)

    {

        return double.IsNaN(value) ? null : value;

    }

}



public class Entity

{

    [Key]

    public int Id { get; set; }

    public double NullableValue { get; set; }

    public double StringValue { get; set; }

}

And that is the generated code:

migrationBuilder.CreateTable(

                name: "Entities",

                columns: table => new

                {

                    Id = table.Column<int>(type: "int", nullable: false)

                        .Annotation("SqlServer:Identity", "1, 1"),

                    NullableValue = table.Column<double>(type: "float", nullable: false),

                    StringValue = table.Column<string>(type: "nvarchar(max)", nullable: false)

                },

                constraints: table =>

                {

                    table.PrimaryKey("PK_Entities", x => x.Id);

                });

EF Core version: 8.0.4

Database provider: Microsoft.EntityFrameworkCore.SqlServer

Target framework: .NET 8.0

Operating system: W10

IDE: Visual Studio 2022 17.8.6 & JetBrains Rider 2024.1.1

Solution as .zip