Table Value Function mapping with Entity Framework 6.3 - entity-framework-6

Question

How do I map table value functions in Code with Entity Framework 6.3? I'm trying to a DB Context in code with an existing database, because EDMX is currently not supported in ASP.NET Core 3. I've tried setting up my DbContext clasee as below. I can successfully query the Grade table. But when I try to query my function "fn_GetCatgeories", I get the following error: No EdmType found for type 'WebApplication6.Data.ApplicationContext+fn_GetCategories'.
public class ApplicationContext : DbContext
{
public ApplicationContext(string cstr)
: base(cstr)
{
Database.SetInitializer<ApplicationContext>(null);
}
[Table("Grade")]
public class Grade
{
[Key]
public string Grade_ID { get; set; }
public string SchoolType { get; set; }
public int Sortorder { get; set; }
}
public partial class fn_GetCategories
{
public int Category_ID { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public Nullable<bool> Active { get; set; }
public Nullable<System.DateTime> Month { get; set; }
public Nullable<int> Order { get; set; }
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Add(new FunctionsConvention<ApplicationContext>("dbo"));
base.OnModelCreating(modelBuilder);
}
[DbFunction("ApplicationContext", "fn_GetCategories")]
public IQueryable<fn_GetCategories> GetCategories(Nullable<System.DateTime> month)
{
var monthParameter = month.HasValue ?
new ObjectParameter("Month", month) :
new ObjectParameter("Month", typeof(System.DateTime));
return ((IObjectContextAdapter)this).ObjectContext.CreateQuery<fn_GetCategories>(string.Format("[0].{1}", GetType().Name, "[fn_GetCategories](#Month)"), monthParameter);
}
// DbSets here
public DbSet<Grade> Grades { get; set; }
}

Answer 1

This works:
public class ApplicationContext : DbContext
{
public ApplicationContext(string cstr)
: base(cstr)
{
Database.SetInitializer<ApplicationContext>(null);
}
[Table("Grade")]
public class Grade
{
[Key]
public string Grade_ID { get; set; }
public string SchoolType { get; set; }
public int Sortorder { get; set; }
}
public partial class fn_GetCategories_Result
{
[Key]
public int Category_ID { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public Nullable<bool> Active { get; set; }
public Nullable<System.DateTime> Month { get; set; }
public Nullable<int> Order { get; set; }
}
// DbSets here
public DbSet<Grade> Grades { get; set; }
public DbSet<fn_GetCategories_Result> fn_GetCategoriesSet { get; set; }
public List<fn_GetCategories_Result> fn_GetCategories(DateTime month)
{
var m = new SqlParameter("Month", DateTime.Now);
return this.fn_GetCategoriesSet.SqlQuery("select * from dbo.fn_GetCategories(#month)", m).ToList();
}