1.Equals & IsNullOrEmpty

要求—-想要对Point类写一个类似string.IsNullOfEmpty的函数检查经纬度是否为0即Empty

  1. public class Point
  2. {
  3.    public double Lat{get;set;}
  4.    public double Lon{get;set;}
  5.    public string Tag{get;set;}
  6.    public Person(double lon, double lat)
  7.    {
  8.        this.Lat = lat;
  9.        this.Lon = lon;
  10.    }  
  12.    public Point(double lon,double lat,string tag)
  13.    {
  14.        this.Lon = lon;
  15.        this.Lat = lat;
  16.        this.Tag = tag;
  17.    }
  18. }

想到了重写Equals的步骤—-在VS中写Equals并Tab两次则会出现完整的Equals函数

  1.        // override object.Equals
  2.         public override bool Equals(object obj)
  3.         {
  4.             if (obj == null)
  5.             {
  6.                 return false;
  7.             }
  8.             if ((obj.GetType().Equals(this.GetType())) == false)
  9.             {
  10.                 return false;
  11.             }
  12.             Point point = null;
  13.             point = (Point)obj;
  14.             return this.Lat.Equals(point.Lat) && this.Lon.Equals(point.Lon);
  15.         }
  17.         // override object.GetHashCode
  18.         public override int GetHashCode()
  19.         {
  20.             return this.Lat.GetHashCode() + this.Lon.GetHashCode();
  21.         }

然后再写IsNullOrEmpty函数

  1.         public static bool IsNullOrEmpty(Point p)
  2.         {
  3.             if (p == null)
  4.             {
  5.                 return true;
  6.             }
  7.             else if (p.Equals(new Point(0, 0)))
  8.             {
  9.                 return true;
  10.             }
  11.             else
  12.             {
  13.                 return false;
  14.             }
  15.         }

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