C# 4 and .NET 4

User-Defined Types ❘ 961
With the variables longitude and latitude, the longitude and latitude values are stored using seconds.
The constructor with seven integer parameters converts degrees, minutes, and seconds to seconds, and sets
the longitude and latitude to negative values if the coordinate is based in the South or West:
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;
}
}
The INullable interface defines the property IsNull, which must be implemented to support nullability.
The static property Null is used to create an object that represents a null value. In the get accessor a
SqlCoordinate object is created, and the isNull field is set to true:
public bool IsNull
{
get
{
return isNull;
}
}
public static SqlCoordinate Null
{
get
{
return new SqlCoordinate { isNull = true };
}
}
A UDT must be converted from and to a string. For conversion to a string, the ToString() method of the
Object class must be overridden. The variables longitude and latitude are converted in the following
code for a string representation to show the degrees, minutes, and seconds notation:
public override string ToString()
{
if (this.isNull)
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