// implementation of CompareTo method
// comapres first by State,then City,
// then streetName and Address number
// then apartment unit
// Exception if( Null object found )
public int CompareTo(Object alpha)
{
if (alpha == null)
{
throw new ArgumentNullException("Property object being compared with is NULL");
}
Property rightOp = alpha as Property;
if (rightOp != null)
{
if (State.ToLower().CompareTo(rightOp.State.ToLower()) == 0)
{
if (City.ToLower().CompareTo(rightOp.City.ToLower()) == 0)
{
if (StreetName.ToLower().CompareTo(rightOp.StreetName.ToLower()) == 0)
{
if (AddNumber.CompareTo(rightOp.AddNumber) == 0)
{
if (rightOp is Apartment)
{
Apartment rightObject = (Apartment)rightOp;
Apartment thisObject = (Apartment)this;
return(thisObject.Unit.ToLower().CompareTo(rightObject.Unit.ToLower()));
}
else
{
return(0); //becasue we have more typies of property now, if the addresses are the same, then the ranking of two properties are the same
//throw new ArgumentNullException("Error:the address of house has been inputted");
}
}
else
{
return(AddNumber.CompareTo(rightOp.AddNumber));
}
}
else
{
return(StreetName.CompareTo(rightOp.StreetName));
}
}
else
{
return(City.CompareTo(rightOp.City));
}
}
else
{
return(State.CompareTo(rightOp.State));
}
}
else
{
throw new ArgumentNullException("Property object being compared with is NULL");
}
}