事务脚本实现答案

【问题标题】：Transaction script implementation事务脚本实现
【发布时间】：2016-12-10 15:29:22
【问题描述】：

您能否告诉我这两种（如果有的话）事务脚本模式中哪一种是正确的？

基本上我需要实现“纯”TS，也就是不以某种方便的方式弯曲它。问题是当我从表数据网关获取数据时，我应该存储它们，用于事务的不同部分（为了清楚起见的逻辑部分）并在我需要的地方使用它们，或者获取数据不存储它们而是直接使用它们如果需要相同的数据再次调用表网关并要求它。

示例：http://pastebin.com/hGCgrfEs

谢谢。希望如果不让我知道它是有道理的:)

【问题讨论】：

标签： c# design-patterns transactions dto

【解决方案1】：

TSDoSomething2 类更接近于一个好的解决方案，我建议这样做来实现一个 SOLID 成绩单实现：

public class OrderBusiness : IAcceptVisitOrder
{
    private readonly string _id;

    private int _status;

    public OrderBusiness(string id, int status)
    {
        _id = id;
        _status = status;
    }

    public void ChangeStatus(int newStatus)
    {
        //validation logic....
        _status = newStatus;
    }

    public void Accept(IOrderVisitor visitor)
    {
        if (visitor == null) throw new ArgumentNullException(nameof(visitor));
        visitor.Visit(_id, _status);
    }
}

public class Client
{
    private readonly OrderApplicationService _service;
    //Get from Service locator like ninject, etc
    private readonly IReader<OrderBusiness, string> _reader = new OrderBusinessReader();
    private readonly IOrderVisitor _visitor = new UpdateOrderVisitor();

    public Client()
    {
        _service = new OrderApplicationService(_reader, _visitor);
    }
    public void Run(UpdateOrderCommand command)
    {
        _service.When(command);
    }
}

public class UpdateOrderCommand
{
    [Required]
    public string Id { get; set; }
    [Required]
    public int Status { get; set; }
}

public class OrderApplicationService
{
    private readonly IReader<OrderBusiness, string> _reader;
    private readonly IOrderVisitor _visitor;

    public OrderApplicationService(IReader<OrderBusiness, string> reader, IOrderVisitor visitor)
    {
        if (reader == null) throw new ArgumentNullException(nameof(reader));
        if (visitor == null) throw new ArgumentNullException(nameof(visitor));
        _reader = reader;
        _visitor = visitor;
    }

    public void When(UpdateOrderCommand command)
    {
        var order = GetBusinessObject(command.Id);
        order.ChangeStatus(command.Status);
        order.Accept(_visitor);
    }

    private OrderBusiness GetBusinessObject(string id)
    {
        if (id == null) throw new ArgumentNullException(nameof(id));
        return _reader.Read(id);
    }
}

public interface IReader<out T, in TK>
{
    T Read(TK id);
}

public interface IAcceptVisitOrder
{
    void Accept(IOrderVisitor visitor);
}

public interface IOrderVisitor
{
    void Visit(string id, int status);
}

public class OrderBusinessReader : IReader<OrderBusiness, string>
{
    public OrderBusiness Read(string id)
    {
        //Read data from db with EF, ADO.NET, ETC
        var status = 0;
        return new OrderBusiness(id, status); 
    }
}

class UpdateOrderVisitor : IOrderVisitor
{
    public void Visit(string id, int status)
    {
        //Persist to database, etc
    }
}

希望这会有所帮助！
问候！

【讨论】：