EF 6.x和EF Core实现返回dynamic类型

前言

未曾想需要直接返回dynamic，多次尝试未能实现，最终还是在stackoverflow上找到了解决方案，特此备忘录。

        public static dynamic SqlQuery(this Database database, string sql, params object[] parameters)
        {
            TypeBuilder builder = CreateTypeBuilder(
                    "DynamicAssembly", "DynamicModule", "DynamicType");

            using (var cmd = database.Connection.CreateCommand())
            {
                try
                {
                    cmd.CommandText = sql;

                    if (cmd.Connection.State != ConnectionState.Open)
                    {
                        cmd.Connection.Open();
                    }

                    cmd.CommandTimeout = cmd.Connection.ConnectionTimeout;

                    foreach (var param in parameters)
                    {
                        cmd.Parameters.Add(param);
                    }

                    using (IDataReader reader = cmd.ExecuteReader())
                    {
                        var schema = reader.GetSchemaTable();

                        foreach (DataRow row in schema.Rows)
                        {
                            var name = (string)row["ColumnName"];
                            var type = (Type)row["DataType"];
                            if (type != typeof(string) && (bool)row.ItemArray[schema.Columns.IndexOf("AllowDbNull")])
                            {
                                type = typeof(Nullable<>).MakeGenericType(type);
                            }
                            CreateAutoImplementedProperty(builder, name, type);
                        }
                    }
                }
                finally
                {
                    database.Connection.Close();
                    cmd.Parameters.Clear();
                }
            }

            var resultType = builder.CreateType();

            return database.SqlQuery(resultType, sql, parameters);
        }

        public static TypeBuilder CreateTypeBuilder(
              string assemblyName, string moduleName, string typeName)
        {
            TypeBuilder typeBuilder = AppDomain
                .CurrentDomain
                .DefineDynamicAssembly(new AssemblyName(assemblyName), AssemblyBuilderAccess.Run)
                .DefineDynamicModule(moduleName)
                .DefineType(typeName, TypeAttributes.Public);
            typeBuilder.DefineDefaultConstructor(MethodAttributes.Public);
            return typeBuilder;
        }

        public static void CreateAutoImplementedProperty(
            TypeBuilder builder, string propertyName, Type propertyType)
        {
            const string PrivateFieldPrefix = "m_";
            const string GetterPrefix = "get_";
            const string SetterPrefix = "set_";

            // Generate the field.
            FieldBuilder fieldBuilder = builder.DefineField(
                string.Concat(PrivateFieldPrefix, propertyName), propertyType, FieldAttributes.Private);

            // Generate the property
            PropertyBuilder propertyBuilder = builder.DefineProperty(
                propertyName, System.Reflection.PropertyAttributes.HasDefault, propertyType, null);

            // Property getter and setter attributes.
            MethodAttributes propertyMethodAttributes =
                MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig;

            // Define the getter method.
            MethodBuilder getterMethod = builder.DefineMethod(
                string.Concat(GetterPrefix, propertyName),
                propertyMethodAttributes, propertyType, Type.EmptyTypes);

            // Emit the IL code.
            // ldarg.0
            // ldfld,_field
            // ret
            ILGenerator getterILCode = getterMethod.GetILGenerator();
            getterILCode.Emit(OpCodes.Ldarg_0);
            getterILCode.Emit(OpCodes.Ldfld, fieldBuilder);
            getterILCode.Emit(OpCodes.Ret);

            // Define the setter method.
            MethodBuilder setterMethod = builder.DefineMethod(
                string.Concat(SetterPrefix, propertyName),
                propertyMethodAttributes, null, new Type[] { propertyType });

            // Emit the IL code.
            // ldarg.0
            // ldarg.1
            // stfld,_field
            // ret
            ILGenerator setterILCode = setterMethod.GetILGenerator();
            setterILCode.Emit(OpCodes.Ldarg_0);
            setterILCode.Emit(OpCodes.Ldarg_1);
            setterILCode.Emit(OpCodes.Stfld, fieldBuilder);
            setterILCode.Emit(OpCodes.Ret);

            propertyBuilder.SetGetMethod(getterMethod);
            propertyBuilder.SetSetMethod(setterMethod);
        }

            using (var ctx = new EfDbContext())
            {
                ctx.Database.Log = Console.WriteLine;

                dynamic queryResult = ctx.Database.SqlQuery("select o.*,c.Name from dbo.Orders as o left join dbo.Customers as c on o.CustomerId = c.Id");
                var ordersJson = JsonConvert.SerializeObject(queryResult);
                var orders = JsonConvert.DeserializeObject<List<Order>>(ordersJson);
            };

来自于：https://stackoverflow.com/questions/26749429/anonymous-type-result-from-sql-query-execution-entity-framework

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