CODEWITHSUNDEEP
c#wpfarraylist
ASHOK A
ASHOK A

Reputation: 2026

How to sort the array list by subsequent number in wpf?

ArrayList SortItems = new ArrayList();
        SortItems.Add("Item1");
        SortItems.Add("Item2");
        SortItems.Add("Item3");
        SortItems.Add("Item4");
        SortItems.Add("Item5");
        SortItems.Add("Item6");
        SortItems.Add("Item7");
        SortItems.Add("Item8");
        SortItems.Add("Item9");
        SortItems.Add("Item10");
        SortItems.Add("Item11");

        SortItems.Sort();

If i run this program, i will get the below result

enter image description here

But i want to sort the list like Item1,Item2,Item3,Item4,Item5,Item6,Item7,Item8,Item9,Item10,Item11

Upvotes: 1

Views: 1296

Answers (5)

Tim Schmelter
Tim Schmelter

Reputation: 460288

If it's always prepended with "Item", you can split both and order by the numic part.

Note that i'll use a strongly typed List<String> instead:

List<String> SortItems = list.Select(s => new
                              {
                                  Item = s, 
                                  Number = int.Parse(s.Substring("Item".Length))
                              }).OrderBy(x => x.Number)
                              .Select(x => x.Item).ToList();

or you can use this Sort method overload to sort the original list directly:

list.Sort((a, b) =>  
    int.Parse(a.Substring("Item".Length)).CompareTo(int.Parse(b.Substring("Item".Length)))
);

Upvotes: 0

waldrumpus
waldrumpus

Reputation: 2590

The result is sorted that way because it uses lexicographic ordering on the strings. The comparison algorithm compares two strings from left to right, and since "1" is less than "9", "10" will be less than "9", too.

You could pad the numeric parts of your strings with zeroes, e.g. "Item05" instead of "Item5".

The more generic and flexible way is to use ArrayList.Sort(IComparer), and implement an IComparer that understands your string format and can order the strings correctly.

Upvotes: 1

xing
xing

Reputation: 447

You can implement a IComparer and pass it to the Sort method.

http://msdn.microsoft.com/en-us/library/0e743hdt.aspx

Upvotes: 0

cuongle
cuongle

Reputation: 75326

Build custom comparer:

public class CusComparer: IComparer
{
    public int Compare(object x, object y)
    {
        return int.Parse((x as string).Substring(4)) - int.Parse((y as string).Substring(4));
    }
}

So you can use:

ArrayList SortItems = new ArrayList();
SortItems.Add("Item1");
SortItems.Add("Item2");
SortItems.Add("Item3");
SortItems.Add("Item4");
SortItems.Add("Item5");
SortItems.Add("Item6");
SortItems.Add("Item7");
SortItems.Add("Item8");
SortItems.Add("Item9");
SortItems.Add("Item10");
SortItems.Add("Item11");

SortItems.Sort(new CusComparer());

But instead of using ArrayList, you should consider using List<T> with stronger type

Upvotes: 4

tempidope
tempidope

Reputation: 873

Your question does not show what kind of result it is giving.

Use SortedList. As and when you add new item, it would be sorted. http://msdn.microsoft.com/en-us/library/system.collections.sortedlist.aspx Downside would be, you cannot have a repetition in the inputs.

Upvotes: 0

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