使用 IComparer 进行排序 [英] Using IComparer for sorting
问题描述
我正在尝试使用 IComparer
对点列表进行排序.这是 IComparer 类:
I am trying to use an IComparer
to sort a list of Points. Here is the IComparer class:
public class CoordinatesBasedComparer : IComparer
{
public int Compare(Object q, Object r)
{
Point a = (p)q;
Point b = (p)r;
if ((a.x == b.x) && (a.y == b.y))
return 0;
if ((a.x < b.x) || ((a.x == b.x) && (a.y < b.y)))
return -1;
return 1;
}
}
在客户端代码中,我尝试使用此类对点 p 列表进行排序(List
类型):
In the client code, I am trying to using this class for sorting a list of points p (of type List<Point>
):
CoordinatesBasedComparer c = new CoordinatesBasedComparer();
Points.Sort(c);
代码出错了.显然,它期望 IComparer
作为 sort 方法的参数.
我需要做什么来解决这个问题?
The code errors out. Apparently it is expecting IComparer<Point>
as argument to sort method.
What do I need to do to fix this?
推荐答案
您需要实现强类型接口 (MSDN).
You need to implement the strongly type interface (MSDN).
public class CoordinatesBasedComparer : IComparer<Point>
{
public int Compare(Point a, Point b)
{
if ((a.x == b.x) && (a.y == b.y))
return 0;
if ((a.x < b.x) || ((a.x == b.x) && (a.y < b.y)))
return -1;
return 1;
}
}
顺便说一句,我认为您使用了太多大括号,我相信只有在它们对编译器有贡献时才应该使用它们.这是我的版本:
BTW, I think you use too many braces, I believe they should be used only when they contribute to the compiler. This is my version:
if (a.x == b.x && a.y == b.y)
return 0;
if (a.x < b.x || (a.x == b.x && a.y < b.y))
return -1;
就像我不喜欢人们使用 return (0)
一样.
Just like I dislike people using return (0)
.
请注意,如果您的目标是 .Net-3.5+ 应用程序,您可以使用 LINQ,它在排序时更容易、更快.
Note that if you target a .Net-3.5+ application you can use LINQ which is easier and even faster with sorting.
LINQ 版本可以是这样的:
LINQ vesion can be something like:
var orderedList = Points.OrderBy(point => point.x)
.ThenBy(point => point.y)
.ToList();
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