IComparer question

[christriddle@googlemail.com]

Hi,

I want to be able to sort a ArrayList of Points, for example, in one of
two (or more) ways depending of the nature of the Points in the
ArrayList. Basically I want two different comparers, both of which I
could use when I want. E.g. one to sort the points in order of their X
value and another for their Y value.

I have no trouble setting up a single comparer, but I don't know how do
accomplish the task above. Any help would be appreciated!!

For example, the code I would like to use:

if (MaxX(Points) < 0)
Points.Sort(); //By X value
else
Points.Sort(); //By Y value


Thanks in advance...
Chris Riddle

[Jianwei Sun]

Re: IComparer question

Instead of using ArrayList.Sort( ), you really should call
ArrayList.Sort( IComparer), and pass in different implementation of
IComparer.

HTH.
christriddle@go oglemail.com wrote:

Hi,
>
I want to be able to sort a ArrayList of Points, for example, in one of
two (or more) ways depending of the nature of the Points in the
ArrayList. Basically I want two different comparers, both of which I
could use when I want. E.g. one to sort the points in order of their X
value and another for their Y value.
>
I have no trouble setting up a single comparer, but I don't know how do
accomplish the task above. Any help would be appreciated!!
>
For example, the code I would like to use:
>
if (MaxX(Points) < 0)
Points.Sort(); //By X value
else
Points.Sort(); //By Y value
>
>
Thanks in advance...
Chris Riddle
>

[Riddle]

Re: IComparer question

Thanks for the quick reply.

This is what I thought originally, but how do I implment this new
Icomparer? Is it external to the class I want to compare? Sorry, having
a bit of a slow day today!

Thanks,
Chris

[Claes Bergefall]

Re: IComparer question

You can implement it anywhere you'ld like. Have its constructor take an
argument specifying the sort order that you want to use. Something like
this:

public class MyComparer : IComparer
{
private bool m_sortByX;
public MyComparer(bool sortByX)
{
m_sortByX = sortByX;
}
public int Compare(object x, object y)
{
// Sort in different order depending on m_sortByX
}
}
....
if (MaxX(Points) < 0)
Points.Sort(new MyComparer(true )); //By X value
else
Points.Sort(new MyComparer(fals e)); //By Y value


/claes

"Riddle" <christriddle@g ooglemail.comwr ote in message
news:1152628995 .482700.121670@ m73g2000cwd.goo glegroups.com.. .

Thanks for the quick reply.
>
This is what I thought originally, but how do I implment this new
Icomparer? Is it external to the class I want to compare? Sorry, having
a bit of a slow day today!
>
Thanks,
Chris
>

[Riddle]

Re: IComparer question

A ha... Thanks very much for you help.
I understand now.

Thanks again!
Chris