How to sort ArrayList(int)

c# .net asp.net sorting arraylist

18,053

Solution 1

You can use list.Sort() for ascending order. For descending order, you need to reverse the order by implementing IComparer. Something like this will do:

// calling normal sort:
ArrayList ascendingList = list.Sort();

// calling reverse sort:
ArrayList descendingList = list.Sort(new ReverseSort());

// implementation:
public class ReverseSort : IComparer
{
    public int Compare(object x, object y)
    {
        // reverse the arguments
        return Comparer.Default.Compare(y, x);
    }

}

Note that, like Jon Skeet mentions in the comment thread under the main question, you do not need to use the untyped ArrayList at all. Instead, you can use the generic List<T>, which is typesafe and is simply more versatile.

Solution 2

You can use list.Sort() function. see example here http://msdn.microsoft.com/ru-ru/library/0e743hdt.aspx

Solution 3

You can you use ArrayList.Sort Method

Solution 4

ArrayList contains a Sort method. (Edited to remove incorrect .NET information)

View more solutions

18,053

Ram

Updated on June 04, 2022

Comments

Ram almost 2 years
How can I sort the Arraylist in ascending and descending orders. Example.
```
ArrayList list= new ArrayList();
list.Add(2);
list.Add(8);
list.Add(0);
list.Add(1);
```
How can I sort the above list in both ascending and descending order?
- Jon Skeet almost 13 years
  
  That's not valid C# code (Add, not add). Why are you using the non-generic ArrayList type anyway? Are you using .NET 1.1 for some reason?
- Ram almost 13 years
  
  Ya. list.add(). that is wrong only sorry for that.I want to sort the arraylist since i'm dynamically adding the values in codebehind.Can u suggest someother collection which supports sorting
- Jon Skeet almost 13 years
  
  No, you mean list.Add. ArrayList has always been sortable, but without knowing why you're using a non-generic type rather than the rather nice List<T> it's hard to advise you well.
- Aisah Hamzah almost 13 years
  
  Another question is, probably: what type of sort do you expect? Since each element is an object, do you want them compared as strings, or numerically?
Ram almost 13 years

Can you explain me briefly or can u provide me any link
Mark Schadler almost 13 years

See this page for documentation of the ArrayList class. msdn.microsoft.com/en-us/library/… There you can find information on the Sort method. You will have to implement a comparator to sort in ASC vs DSC, however examples are provided in the documentation of this.
Jon Skeet almost 13 years

It's contained a Sort method since 1.0 - certainly in 1.1: msdn.microsoft.com/en-us/library/895sadkk(v=VS.71).aspx
Admin over 2 years

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