I have the problem of wanting to extract an element from an ArrayList as such, because when I have to use that element for some operation, it tells me that it is of type object, here is the example
ArrayList Lista = new ArrayList() { 1, 3, 4, "100" };
Console.WriteLine(Lista[1]+2);
In this case the output would be 5 , but as explained before the problem is that it tells me that it is object type and that the operation can not be carried out.
If you are forced to use ArrayList because the elements can be of any type, you will have to cast / convert the elements before using them. For example:
ArrayList Lista = new ArrayList() { 1, 3, 4, "100" };
foreach(var l in Lista) {
if (l is int)
Console.WriteLine(((int) l) + 2);
if (l is string)
Console.WriteLine(int.Parse(l) + 2);
// etc para los distintos tipos de datos
}
ArrayList stores the data as object type so you need to cast the corresponding data type to perform the operation in this case int:
Console.WriteLine(Convert.ToInt32(Lista[1]) + 2);
or alternatively
Console.WriteLine((int)(Lista[1]) + 2);
ArrayList stores data type Object if you want to avoid caster usa generics example
List<int> list1 = new List<int>();
This way you avoid the casting and if you get to put a different data type you will get the error in compile time, besides being a value with a declared data type what you are saving in the generic list is much faster than saving an object type