课的一些问题 [英] some problem with classes

问题描述

你好。

我有7个课程，Topaz1，Topaz2，Topaz3 ...... Topaz7都来自Topaz课程。

我需要制作一个根据起始编号和结束编号创建Topaz列表的功能。例如，如果起始编号为3且结束编号为5，则列表应包含Topaz4，Topaz5的元素，如果起始编号为1且结束编号为4，则列表将包含Topaz2类的元素， Topaz3，Topaz4。

如何执行这样的代码？我实际上已经完成了我可能拥有的每一个想法以及长期的谷歌搜索。

Hello.
I have a 7 classes, Topaz1, Topaz2, Topaz3... Topaz7 that all derive from class "Topaz".
I need to make a function that creates a list of "Topaz" according to a starting number and an ending number. For example, if the starting number is 3 and the ending number is 5 then the list should have elements of Topaz4, Topaz5, and if the starting number is 1 and the ending number is 4 the list will have the elements of the classes Topaz2, Topaz3, Topaz4.
How do I execute such a code? I have literally gone through every idea I possibly had and a long google search.

推荐答案

这让我觉得这是一种非常糟糕的做事方式 - 但它非常简单，取决于你究竟想要做什么。

假设你有这样的课程：

This strikes me as a very poor way to do things - but it's pretty simple, depending on what exactly you are trying to do.
Assuming you have classes thus:

public abstract class Topaz { }
public class Topaz1 : Topaz { }
public class Topaz2 : Topaz { }
public class Topaz3 : Topaz { }
public class Topaz4 : Topaz { }
public class Topaz5 : Topaz { }
public class Topaz6 : Topaz { }
public class Topaz7 : Topaz { }

然后如果你正在过滤现有的实例列表，只包含您想要的类型：

Then if you are filtering an existing list of instances to just the types you want:

private List<Topaz> FilterThem(IEnumerable<Topaz> source, int lo, int hi)
    {
    return source.Where(s => InRange(s, lo, hi)).ToList();
    }
private bool InRange(Topaz t, int lo, int hi)
    {
    int n = int.Parse(t.GetType().Name.Substring(5));
    return (lo < n && n <= hi);
    }

如果你想创建实例，那就太麻烦了：

If you are trying to create instances, that's a lot more messy:

private List<Topaz> CreateThem(int lo, int hi)
    {
    List<Topaz> list = new List<Topaz>();
    System.Reflection.Assembly assembly = System.Reflection.Assembly.GetExecutingAssembly();
    string name = assembly.FullName.Split(',')[0] + ".Topaz";
    for (int i = lo + 1; i <= hi; i++)
        {
        list.Add((Topaz)assembly.CreateInstance(name + i));
        }
    return list;
    }

但我仍然认为你在这里做出了一些糟糕的设计决定！

But I still think you have made some poor design decisions here!

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