How to convert an ArrayList to a strongly typed generic list without using a foreach?

user_88204 0
Viewed 59480

See the code sample below. I need the ArrayList to be a generic List. I don't want to use foreach.

ArrayList arrayList = GetArrayListOfInts();  
List<int> intList = new List<int>();  

//Can this foreach be condensed into one line?  
foreach (int number in arrayList)  
{  
    intList.Add(number);  
}  
return intList;
generic-list arraylist list .net c#
4 Answers

Try the following

var list = arrayList.Cast<int>().ToList();

This will only work though using the C# 3.5 compiler because it takes advantage of certain extension methods defined in the 3.5 framework.

JaredPar_232830

This is inefficient (it makes an intermediate array unnecessarily) but is concise and will work on .NET 2.0:

List<int> newList = new List<int>(arrayList.ToArray(typeof(int)));
user_559430

In .Net standard 2 using Cast<T> is better way:

ArrayList al = new ArrayList();
al.AddRange(new[]{"Micheal", "Jack", "Sarah"});
List<int> list = al.Cast<int>().ToList();

Cast and ToList are extension methods in the System.Linq.Enumerable class.

user_90440840
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