Entity Framework Core, UD sql function throws System.NotImplementedException: 'The method or operation is not implemented.'

Question

I am having a lot of trouble trying to run a SQL function from the DbContext, I have tried several suggestions with no luck.

I have a class library project, with Entity Framework Core (3.1.5). The project compiles and runs but when I try to run a unit test (before I deploy or integrate) every time I touch the function I get an error

System.NotImplementedException: 'The method or operation is not implemented.'

This is the SQL function:

CREATE FUNCTION [dbo].[GetLocalDate]()
RETURNS DATETIME
AS
BEGIN
     DECLARE @gd AS DATETIME =  getUTCdate()
     DECLARE @D AS datetimeoffset

     SET @D = CONVERT(datetimeoffset, @gd) AT TIME ZONE 'Central Standard Time'
     RETURN CONVERT(datetime, @D);
END

which is working in the database.

This is my database context:

public class VendorDbContext : DbContext
{
    public VendorDbContext(DbContextOptions options) : base(options)
    { }

    [DbFunction("GetLocalDate", "dbo")]
    public static DateTime GetLocalDate()
    {
        throw new NotImplementedException();
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.HasDbFunction(() => VendorDbContext.GetLocalDate());
    }
}

and this is the call in the class - Context is a local variable of the VendorDbContext type, and Vendor is an existing valid entity in the model:

var now = Context.Vendor.Where(v => v.CompanyId == 6)
                        .Select(v => VendorDbContext.GetLocalDate() ).FirstOrDefault();

Does not matter what I try, I always got the exception mentioned above.

Any ideas please?

Answer 1

I faced same problem. I found reason of this problem for my code. If Entity Framework didn't execute LINQ query and occured local evalution, your DbFunction will execute in C# side. Therefore VendorDbContext.GetLocalDate() called in C# side will throw System.NotImplementedException