My arraylist and array problem?

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I want to add many int[,] arrays in an arraylist but I couldn't extract them in int[,] data type.
This code will demonstrate what i want to do:

arraylist Myarraylist =new arraylist();
int [,] array1 = new int[3,2];
int [,] array2 = new int[5,2];
int [,] array3 = new int[6,4];

Myarraylist.add(array1);
Myarraylist.add(array2);
Myarraylist.add(array3);

I want this semi-code to happen:

int[,] Myarray1 = Myarraylist[1]

but when i extracted them a problem came up that they are objects not even object[,]
but just object. How can I cast them to int[,] again?

Thank you for your help.

Posted 23-May-11 1:32am

Al-Samman Mahmoud

Updated 23-May-11 1:36am

Fabio V Silva

v3

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2 solutions

Solution 2

Don't use the ArrayList; it was rendered obsolete when generics were introduced in v.2.0. Use System.Collections.Generic.List. In your case, use System.Collections.Generic.List<System.Collections.Generic.List<int>>.

It will represent jagged array. Use System.Collections.Generic.List.ToArray to get an array of rank 1. The element will be lists, use each one with ToArray to get nested array elements.

—SA

Posted 23-May-11 5:55am

Sergey Alexandrovich Kryukov

Comments

Al-Samman Mahmoud 24-May-11 8:54am

thank u for ur help and i will use generic it seems to be more accurate and easier.

Sergey Alexandrovich Kryukov 24-May-11 12:47pm

You're welcome.
If you think it's useful please formally accept this answer (you can accept more than 1).
Thank you.
--SA

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CPallini · Accepted Answer · 2011-05-23T01:46:00

You need to cast the dereferenced element, for instance, the following code will work:

C#

ArrayList Myarraylist = new ArrayList();
    int [,] array1 = new int[3,2];
    int [,] array2 = new int[5,2];
    int [,] array3 = new int[6,4];


    Myarraylist.Add(array1);
    Myarraylist.Add(array2);
    Myarraylist.Add(array3);

    // HERE the needed cast
    int[,] Myarray1 = (int[,])Myarraylist[1];

    for (int n = 0; n < 2; n++)
        Console.WriteLine("MyArray1[0,{0}]={1}", n, Myarray1[0, n]);

BTW as the following note (from MSDN[^]) says

Applications that target version 2.0 and later of the .NET Framework should use the generic collection classes in the System.Collections.Generic namespace, which provide greater type-safety and efficiency than their non-generic counterparts.

I strongly suggest you using generic containers instead of ArrayList.