EF 中 自定义的参数查询

EF 中如果要用到自定义的参数查询，则如下扩展可以是查询更加方便

public static class EntityFrameworkDbExtention

    {

        public static IEnumerable<T> SqlQueryParameter <T>(this System.Data.Entity.Database database, string sql, object parameters = null)

        {

            if (parameters == null) return database.SqlQuery<T>(sql);

            using (var tmp_cmd = database.Connection.CreateCommand())

            {

                var dict = ToDictionary(parameters);

                int i = 0;

                var arr = new object[dict.Count];

                foreach (var one_kvp in dict)

                {

                    var param = tmp_cmd.CreateParameter();

                    param.ParameterName = one_kvp.Key;

                    param.Value = one_kvp.Value ?? DBNull.Value;

                    arr[i] = param;

                    i++;

                }

                return database.SqlQuery<T>(sql, arr);

            }

        }

        private static IDictionary<string, object> ToDictionary(object data)

        {

            const BindingFlags attr = System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance;

            return data.GetType().GetProperties(attr).Where(property => property.CanRead).ToDictionary(property => property.Name, property => property.GetValue(data, null));

        }

    }

var p = db.Database.SqlQueryParameter<ppc_account>("select * from ppc_account where id=2").FirstOrDefault();