Question

已经在项目上工作了一段时间，基本上它是C＃和Mysql的组合作为服务器端系统。由于性能问题，我将代码ADO.NET交给我的mysql查询，但我遇到了一个问题，因为我想减少需要编写的代码量。

让我们说

ItemService类有方法（以下代码只是示例）

protected internal List<Item> Read()
    {
        List<Item> itemList = new List<Item>();
        String query = @"SELECT * FROM items";
        itemList = IRead(query);
        return itemList;
    }

protected internal Item Read(int id)
    {
        List<Item> itemList = new List<Item>();
        Item item = new Item();
        String query = String.Format(@"SELECT * FROM items WHERE id = {0}", id);
        itemList = IRead(query);
        item = itemList.FirstOrDefault();
        return item;
    }
 protected internal List<Item> Read(int startId, int limit, String orderBy = "id", String order = "ASC")
    {
        List<Item> itemList = new List<Item>();
        String query = String.Format(@"SELECT * FROM items WHERE id >= {0} ORDER BY '{1}' '{2}' LIMIT {3}", startId, orderBy, order, limit);
        itemList = IRead(query);
        return itemList;
    }

OrderService类具有非常相似的方法

protected internal List<Order> Read()
    {
        List<Order> orderList = new List<Order>();
        String query = @"SELECT * FROM items";
        orderList = IRead(query);
        return orderList;
    }
 protected internal Order Read(int id)
    {
        Order order = new Order();
        String query = String.Format(@"SELECT * FROM invoices WHERE id = {0}", id);
        order = IRead(query).FirstOrDefault();
        return order;
    }

我正在考虑使用抽象类，但是我如何处理不同的返回对象（动态除外）以及方法内的不同字符串查询。非常感谢你的帮助。

Answer 1

您可以创建一个抽象基类，为您完成大部分繁重工作：

public abstract class ItemBase<T> where T : new()
{
    public abstract string table_name { get; }

    protected internal T Read(int id)
    {
        var query = $@"SELECT * FROM {table_name} WHERE id = {id}";
        //var itemList = IRead(query);
        Console.WriteLine(query); //Did this as console output for testing
        return new T(); // temList.FirstOrDefault();
    }

    protected internal List<T> Read(int startId, int limit, string orderBy = "id", string order = "ASC")
    {
        string query = $@"SELECT * FROM {table_name} WHERE id >= {startId} ORDER BY {orderBy} {order} LIMIT {limit}";
        Console.WriteLine(query); //Console output for testing
        return null;
        //return IRead(query);
    }
}

然后你可以像这样创建各个记录类：

public class Item : ItemBase<Item>
{
     public override string table_name => "items";
}

您可以像这样使用它：

//Console Application:
class Program
{
    static void Main(string[] args)
    {
        var i = new Item();
        i.Read(12);
        i.Read(1, 2);
        Console.ReadLine();
    }
}

减少c＃中重复的类似方法

1 个答案: