Sorting a List

Peter

18y6.4kVisual Basic .NET

Hi.

I have a List.

MyObj has a attribute Called Name.

I would like to sort the List i alpfabetical order on the Name attribute.. How do I do that?

Best regards

Peter

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Alan18y ago
Accepted answer
Do you really mean an attribute or do you mean a property called Name?

If it's the latter, then this approach should work (.NET 2.0 or later):

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
       List list = new List();
       list.Add(new MyObj("Peter"));
       list.Add(new MyObj("Alan"));
       list.Add(new MyObj("Joe"));
       list.Add(new MyObj("Fred"));
       list.Sort(CompareByName);
       foreach(MyObj obj in list)
       {
         Console.WriteLine(obj.Name);
       }
       Console.ReadKey();
    }

    static int CompareByName(MyObj obj1, MyObj obj2)
    {
       // compare names ignoring case
       return String.Compare(obj1.Name, obj2.Name, true);
    }
}

class MyObj
{
   string name;

   public string Name
   {
      get { return name;}
   }

   public MyObj(string name)
   {
      this.name = name;
   }
}

Ryan Alford18y ago

here is some sample code. I have a class that has a DateTime property that I wanted to sort by.

1. Your class will need to implement the IComparable interface...

public class YourClassName: IComparable
{

}

2. You need to implement the IComparable method in your class.

int IComparable.CompareTo(object obj)
{
    YourClassName Compare = (YourClassName)obj;
    int result = this.YourSortingProperty.CompareTo(Compare.YourSortingProperty);
    if (result == 0)
        result = Compare.YourSortingProperty.CompareTo(this.YourSortingProperty);
    return result;
}

3. and the code to sort...

List<YourClassName> list = new List<YourClassName>();

//populate your list

list.Sort();