// C# Eval Expression

// Doc: https://eval-expression.net/options

​

// @nuget: Microsoft.EntityFrameworkCore.SqlServer

// @nuget: Z.EntityFramework.Extensions.EFCore

// @nuget: Z.Expressions.Eval

​

/*

## DisableAutoRegisterEntityFramework

​

The DisableAutoRegisterEntityFramework option lets you get or set if the auto registration of some method of Entity Framework Core and EF6, such as being able to use `DbFunctions` and `DbFunctionExtensions` with Dynamic LINQ should be disabled. By default, the DisableAutoRegisterEntityFramework value is `false`.

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In this example, we will query the customers table by filtering it using the `EF.Functions.DateDiffMonth` method and shows all returned customers. By default, the query will work successfully, but if you uncomment the `DisableAutoRegisterEntityFramework = true` option, the query will no longer work and throw an error.

​

​

See more: https://eval-expression.net/options

*/

​

using System;

using System.Collections.Generic;

using System.Linq;

using Microsoft.EntityFrameworkCore;

using Microsoft.Data.SqlClient;

using Z.Expressions;

​

public class Program

{

    public static void Main()

    {

        using (var context = new EntityContext())

        {

            context.Database.EnsureCreated();

            context.Add(new Customer() { Name = "C# Eval Expression", CreatedDate = DateTime.Now });

            context.Add(new Customer() { Name = "ZZZ Projects", CreatedDate = DateTime.Now.AddMonths(-1) });

            context.BulkSaveChanges();

        }

        // Uncomment to make the next query fail

        // EvalManager.DefaultContext.DisableAutoRegisterEntityFramework = true;

        try

        {

            using (var context = new EntityContext())

            {

                var customers = context.Customers.WhereDynamic(x => "EF.Functions.DateDiffMonth(x.CreatedDate, DateTime.Now) == 0").ToList();

                FiddleHelper.WriteTable("1 - ", customers);

            }

        }

        catch (Exception ex)

        {

            Console.WriteLine("2 - Exception: " + ex.Message);

        }

    }

    public class EntityContext : DbContext

    {

        public EntityContext() 

        {

        }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

        {

            optionsBuilder.UseSqlServer(new SqlConnection(FiddleHelper.GetConnectionStringSqlServer()));

​

            base.OnConfiguring(optionsBuilder);

        }

        public DbSet<Customer> Customers { get; set; }

    }

    public class Customer

    {

        public int CustomerID { get; set; }

        public string Name { get; set; }

        public DateTime CreatedDate { get; set; }

    }

}

​

​