Question

此方法检索整个数据。我正在尝试将此方法切换为使用字典的方法，但效果不佳。 INSERT，UPDATE和DELETE已完成，但是SELECT遇到了问题。

我想转换为如下链接源所示的my方法。 https://gist.github.com/thorsman99/e788dd9cce36c26edd9076c9dac288dd

public static List<TestModel> GetList(string id, string subject, string UseYN, string createDate1, string createDate2)
    {
        using(SQLiteConnection connection = new SQLiteConnection(_connection))
        {
            connection.Open();

            using(SQLiteCommand command = new SQLiteCommand(connection))
            {
                command.CommandText = @"SELECT ID, Subject,  CreateDate, UpdateDate FROM Test";

                command.Parameters.Add(new SQLiteParameter(@"ID"         , DbType.String) { Value = id          });
                command.Parameters.Add(new SQLiteParameter(@"Subject"    , DbType.String) { Value = subject     });
                command.Parameters.Add(new SQLiteParameter(@"CreateDate1", DbType.String) { Value = createDate1 });
                command.Parameters.Add(new SQLiteParameter(@"CreateDate2", DbType.String) { Value = createDate2 });

                SQLiteDataReader reader = command.ExecuteReader();

                List<TestModel> list = new List<TestModel>();

                while(reader.Read())
                {
                    TestModel item = new TestModel();

                    item.ID         =                    reader["ID"        ].ToString();
                    item.Subject    =                    reader["Subject"   ].ToString();
                    item.CreateDate = Convert.ToDateTime(reader["CreateDate"]);
                    item.UpdateDate = Convert.ToDateTime(reader["UpdateDate"]);

                    list.Add(item);
                }

                return list;
            }
        }
    }

Answer 1

我移动了connection.Open to directly before the。ExecuteReader`连接应该在最短的时间内打开。我将Dictionary的声明移到using块之外，然后将return也移到外部。再次是要尽快关闭连接。

我将2个使用块组合为一个。只是稍微简化了代码并节省了缩进量。

对于字典，我使用“ ID”作为键。我以为这是主键，因此是唯一的。

        public Dictionary<string, TestModel> GetTestModelDictionary(string id, string subject, string UseYN, string createDate1, string createDate2)
        {
            Dictionary<string, TestModel> dict = new Dictionary<string, TestModel>();
            using (SQLiteConnection connection = new SQLiteConnection(_connection))
            using (SQLiteCommand command = new SQLiteCommand(connection))
            {
                command.CommandText = @"SELECT ID, Subject,  CreateDate, UpdateDate FROM Test";

                command.Parameters.Add(new SQLiteParameter(@"ID", DbType.String) { Value = id });
                command.Parameters.Add(new SQLiteParameter(@"Subject", DbType.String) { Value = subject });
                command.Parameters.Add(new SQLiteParameter(@"CreateDate1", DbType.String) { Value = createDate1 });
                command.Parameters.Add(new SQLiteParameter(@"CreateDate2", DbType.String) { Value = createDate2 });
                connection.Open();
                SQLiteDataReader reader = command.ExecuteReader();
                while (reader.Read())
                {
                    TestModel item = new TestModel();

                    item.ID = reader["ID"].ToString();
                    item.Subject = reader["Subject"].ToString();
                    item.CreateDate = Convert.ToDateTime(reader["CreateDate"]);
                    item.UpdateDate = Convert.ToDateTime(reader["UpdateDate"]);

                    dict.Add(item.ID, item);
                }
            }
            return dict;
        }

如何将List <Generic>转换为字典选择查询？

1 个答案: