C#学习笔记7

public class Coordinate
{
    /// <summary>
    /// 经度
    /// </summary>
    public Angle Longitude { get; set; }
    /// <summary>
    /// 维度
    /// </summary>
    public Angle Latitude { get; set; }

    public override int GetHashCode()
    {
        int hashCode = Longitude.GetHashCode();
        if (hashCode != Latitude.GetHashCode())
        {
            hashCode ^= Latitude.GetHashCode();
        }
        return hashCode;
    }

    public override bool Equals(object obj)
    {
        if (obj == null)
        {
            return false;
        }
        return Equals((Coordinate)obj);
    }

    public bool Equals(Coordinate obj)
    {
        if (obj == null)
        {
            return false;
        }
        if (GetHashCode() != obj.GetHashCode())
        {
            return false;
        }
        return Longitude.Equals(obj.Longitude) && Latitude.Equals(obj.Latitude);
    }

    public static bool operator ==(Coordinate one, Coordinate two)
    {
        if (ReferenceEquals(one, null))//此处不用==判断null，是因为我们重定义了本类的“==”操作符，否则会进入递归造成死循环。
        {
            return ReferenceEquals(two, null);
        }
        return one.Equals(two);
    }

    public static bool operator !=(Coordinate one, Coordinate two)
    {
        return !(one == two);
    }

    public static Coordinate operator +(Coordinate one, Coordinate two)
    {
        return new Coordinate()
        {
            Longitude = one.Longitude + two.Longitude,
            Latitude = one.Latitude + two.Latitude
        };
    }

    public static bool operator !(Coordinate one)
    {
        return false;
    }

    public static bool operator true(Coordinate one)
    {
        return one.Latitude.Hours > 0 && one.Latitude.Minutes > 0 && one.Latitude.Seconds > 0;
    }

    public static bool operator false(Coordinate one)
    {
        if (one)
        {
            return false;
        }
        return true;
    }
}

public struct Angle
{
    public Angle(int hours, int minutes, int seconds)
    {
        Hours = hours;
        Minutes = minutes;
        Seconds = seconds;
    }
    public int Hours { get; set; }
    public int Minutes { get; set; }
    public int Seconds { get; set; }

    public Angle Move(int hours, int minutes, int seconds)
    {
        return new Angle(Hours + hours, Minutes + minutes, Seconds + seconds);
    }

    public override int GetHashCode()
    {
        return base.GetHashCode();
    }

    public override bool Equals(object obj)
    {
        return Equals((Angle)obj);
    }

    public bool Equals(Angle obj)
    {
        return Hours == obj.Hours && Minutes == obj.Minutes && Seconds == obj.Seconds;
    }

    public static Angle operator +(Angle one, Angle two)
    {
        return one.Move(two.Hours, two.Minutes, two.Seconds);
    }

    public static implicit operator string(Angle one)
    {
        return string.Format("{0},{1},{2}", one.Hours, one.Minutes, one.Seconds);
    }

    public static explicit operator Angle(string text)
    {
        try
        {
            var result = text.Split(',').Cast<int>();
            return new Angle(result.ElementAt(0), result.ElementAt(1), result.ElementAt(2));
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }
}

public class TemporaryFileStream : IDisposable
{
    public TemporaryFileStream(string fileName)
    {
        //todo
    }

    ~TemporaryFileStream()
    {
        Dispose();
    }

    private readonly FileStream _stream;
    public FileStream Stream
    {
        get { return _stream; }
    }

    private readonly FileInfo _file;
    public FileInfo File
    {
        get { return _file; }
    }

    public void Dispose()
    {
        Stream?.Close();
        File?.Delete();
        /*该语句的作用是从终结列队中移除TemporaryFileStream类实例，一个对象在终结列队中就是不会进行垃圾回收，必须终结后才能垃圾回收，执行此语句就不会推迟该对象的
        垃圾回收。*/
        GC.SuppressFinalize(this);
    }
}

public class DataCache
{
    public DataCache()
    {
        _fileStream = new Lazy<TemporaryFileStream>(() => new TemporaryFileStream(FileStreamName));
    }
    public string FileStreamName { get; set; }

    private Lazy<TemporaryFileStream> _fileStream;
    public TemporaryFileStream FileStream
    {
        //只有在返回“value”时，才会执行“() => new TemporaryFileStream(FileStreamName)”代码，
        get { return _fileStream.Value; }
    }

    /* .net4.0以前模拟的延迟初始化对象
    private TemporaryFileStream _fileStream;
    public TemporaryFileStream FileStream
    {
        get
        {
            if (_fileStream == null)
            {
                _fileStream = new TemporaryFileStream(FileStreamName);
            }
            return _fileStream;
        }
    }*/
}