Exist Finder classes to find elements into List?

jeusdi · February 11th, 2007, 02:09 PM

So, I would like me know if exist any library or utility in order to find a group of elements added into ArrayList.

    Mmm, Now I find elements as follow:

       System.Collections.ArrayList result = new System.Collections.ArrayList();
            foreach (Element element in elements)
            {
                //Criterium-->
                if (element.Code == "X")
                {
                    result.Add(client);
                }
            }
            return result;

I would like me to use as a Finder class or something.

Can you help me please?

fbailey · February 11th, 2007, 06:05 PM

Collection is a collection.
Your Data Structure (element with a time field) can add to the capabilties of the Collection.
Maybe you can create your own class, with some other features, of having a sub collecton, that I dont know.
Nor do I know the correct answer to this question.

I hope this is of help.

planoie · February 12th, 2007, 01:02 PM

Usually this is done with a custom collection. Extend the CollectionBase class to create your own collection type that as custom finder methods. The methods can be implemented as standard methods or as indexers. Here's how I would implement it:

Code:

    public class MyClass
    {
    }
    public class MyClassCollection : System.Collections.CollectionBase
    {
        public int Add(MyClass item)
        {
            return this.InnerList.Add(item);
        }
        public MyClass FindItem(string test){
            for (int i = 0; i < this.InnerList.Count; i++)
            {
                if(this[i].<property> == <test condition>){
                    return this[i];
                }
            }
        }
        public MyClass this[int index]
        {
            get { return (MyClass)this.InnerList[index]; }
        }
        public MyClass this[string test]
        {
            get { return FindItem(test); }
        }
    }

-Peter

fbailey · February 14th, 2007, 11:50 AM

So, I would like me know if exist any library or utility in order to find a group of elements added into ArrayList.

    Mmm, Now I find elements as follow:

       System.Collections.ArrayList result = new System.Collections.ArrayList();
            foreach (Element element in elements)
            {
                //Criterium-->
                if (element.Code == "X") 'code seems to me maybe it should be examples not "X" != X <> "X" whatever
                {
                    result.Add(client);
                }
            }
            return result;

Please Excuse me but the code maybe adjusted for whatever you are doing by changing not equal X, I did not notice this before.
I hope I see this correctly its tough replying to something I can not see.

planoie · February 19th, 2007, 01:31 PM

There is no built in method for finding items by an arbitrary test. You have to build methods that do it because you have to define the actual test you will perform to determine which items of the list match your test value. This will always involve iterating thru the list of items and testing each one, then doing whatever you need to with them (whether it's adding them to another list or returning a flag indicating that did or did not find the desired item).

-Peter