如何遍历KeyValuePair类型的列表 [英] How to iterate through list of type KeyValuePair

问题描述

您好我有以下类型的列表

Hi I have following Type of list

private void PositionMatchList()
       {
           List<KeyValuePair<Point, Point>> lp = new List<KeyValuePair<Point, Point>>();
           KeyValuePair<Point, Point> p1 = new KeyValuePair<Point, Point>(new Point(0, 0), new Point(1, 1));
           KeyValuePair<Point, Point> p2 = new KeyValuePair<Point, Point>(new Point(0, 1), new Point(2,1));          
           lp.Add(p1);
           lp.Add(p2);          

       }

我希望在使用Linq传递密钥时获取值。例如，我想得到值（2,1）当键是（0,1）

推荐答案

我想你可以使用通用词典在这里为自己省去了很多麻烦......如果：



1.你的意图不是要有一个可能有的列表KeyValuePairs具有相同的Key：要使用Dictionary，Keys必须是唯一的！

I think you can use a generic Dictionary here and save yourself a lot of trouble ... if:

1. it is not the case that your intent is to have a List where there could be KeyValuePairs that had the same Key: to use a Dictionary the Keys must be unique !

// define the data structure outside your procedure so it can be accessed 
private Dictionary<Point, Point> dctPointPoint = new Dictionary<Point, Point>();

private void PositionMatchList()
{
    dctPointPoint.Add(new Point(0, 0), new Point(1, 1));
    dctPointPoint.Add(new Point(0, 1), new Point(2, 1));

    // this would throw an error: duplicate Key !
    // dctPointPoint.Add(new Point(0, 1), new Point(3, 1));
}

// use it in some method:

// initialize
PositionMatchList();

// access
Point pvalue = dctPointPoint[new Point(0, 1)];

试试这个

Try this

class Point
    {
        public int X { get; set; }
        public int Y { get; set; }
        public Point(int a, int b)
        {
            X = a;
            Y = b;

        }
    }

    Point GetPoint(int key, int value)
    {
        List<KeyValuePair<Point, Point>> lp = new List<KeyValuePair<Point, Point>>();
        KeyValuePair<Point, Point> p1 = new KeyValuePair<Point, Point>(new Point(0, 0), new Point(1, 1));
        KeyValuePair<Point, Point> p2 = new KeyValuePair<Point, Point>(new Point(0, 1), new Point(2, 1));
        lp.Add(p1);
        lp.Add(p2);

        var temp = lp.Where(k => k.Key.X == key && k.Key.Y == value).FirstOrDefault();
        return temp.Value;

    }

试试这个

Try This

public Point GetKeyFromValue(Point p,List<KeyValuePair<Point, Point>> lp)
{
      return lp.Where(d => d.Value == p).Select(d => d.Key).FirstOrDefault();
}

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