sqlcoordinate.cs

来自「C#高级编程第6版随书源代码 值得下载」· CS 代码 · 共 141 行

using System;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;

namespace Wrox.ProCSharp.SqlServer
{

   public enum Orientation
   {
      NorthEast,
      NorthWest,
      SouthEast,
      SouthWest
   }


   [Serializable]
   [Microsoft.SqlServer.Server.SqlUserDefinedType(Format.Native)]
   public struct SqlCoordinate : INullable
   {
      private int longitude;
      private int latitude;
      private bool isNull;

      public SqlCoordinate(int longitude, int latitude)
      {
         isNull = false;
         this.longitude = longitude;
         this.latitude = latitude;
      }

      public SqlCoordinate(int longitudeDegrees, int longitudeMinutes,
         int longitudeSeconds, int latitudeDegrees, int latitudeMinutes,
         int latitudeSeconds, Orientation orientation)
      {
         isNull = false;
         this.longitude = longitudeSeconds + 60 * longitudeMinutes + 3600 *
               longitudeDegrees;
         this.latitude = latitudeSeconds + 60 * latitudeMinutes + 3600 *
               latitudeDegrees;
         switch (orientation)
         {
            case Orientation.SouthWest:
               longitude = -longitude;
               latitude = -latitude;
               break;
            case Orientation.SouthEast:
               longitude = -longitude;
               break;
            case Orientation.NorthWest:
               latitude = -latitude;
               break;
         }
      }


      public override string ToString()
      {
         if (this.isNull)
            return null;

         char northSouth = longitude > 0 ? 'N' : 'S';
         char eastWest = latitude > 0 ? 'E' : 'W';

         int longitudeDegrees = Math.Abs(longitude) / 3600;
         int remainingSeconds = Math.Abs(longitude) % 3600;
         int longitudeMinutes = remainingSeconds / 60;
         int longitudeSeconds = remainingSeconds % 60;

         int latitudeDegrees = Math.Abs(latitude) / 3600;
         remainingSeconds = Math.Abs(latitude) % 3600;
         int latitudeMinutes = remainingSeconds / 60;
         int latitudeSeconds = remainingSeconds % 60;

         return String.Format("{0}°{1}'{2}\"{3},{4}°{5}'{6}\"{7}",
               longitudeDegrees, longitudeMinutes, longitudeSeconds, northSouth,
               latitudeDegrees, latitudeMinutes, latitudeSeconds, eastWest);

      }

      public bool IsNull
      {
         get
         {
            return isNull;
         }

      }

      public static SqlCoordinate Null
      {
         get
         {
            SqlCoordinate c = new SqlCoordinate();
            c.isNull = true;
            return c;

         }
      }

      public static SqlCoordinate Parse(SqlString s)
      {
         if (s.IsNull)
            return SqlCoordinate.Null;

         try
         {
            string[] coordinates = s.Value.Split(',');
            char[] separators = { '°', '\'', '\"' };
            string[] longitudeVals = coordinates[0].Split(separators);
            string[] latitudeVals = coordinates[1].Split(separators);

            Orientation orientation;
            if (longitudeVals[3] == "N" && latitudeVals[3] == "E")
               orientation = Orientation.NorthEast;
            else if (longitudeVals[3] == "S" && latitudeVals[3] == "W")
               orientation = Orientation.SouthWest;
            else if (longitudeVals[3] == "S" && latitudeVals[3] == "E")
               orientation = Orientation.SouthEast;
            else
               orientation = Orientation.NorthWest;

            return new SqlCoordinate(
                  int.Parse(longitudeVals[0]), int.Parse(longitudeVals[1]),
                  int.Parse(longitudeVals[2]),
                  int.Parse(latitudeVals[0]), int.Parse(latitudeVals[1]),
                  int.Parse(latitudeVals[2]), orientation);
         }
         catch (Exception ex)
         {
            throw new ArgumentException(
                  "Argument has a wrong syntax. " +
                  "This syntax is required: 37°47\'0\"N,122°26\'0\"W",
                  ex.Message);
         }

      }
   }


}