CODEWITHSUNDEEP
linqselect
imekon
imekon

Reputation: 1543

Does Linq Select does not work with IList?

I'm working with Visual Studio 2019 and it suggested a conversion for a foreach to Linq which then doesn't compile:

using System.Collections;
using System.Collections.Generic;
using System.Linq;

static void Main(string[] args)
{
    var list = new List<object>();
    list.Add("One");
    list.Add("Two");
    list.Add("Three");

    // To make the point...
    var iList = (IList)list;

    // This doesn't compile and generates CS1061: IList does not contain a definition for Select.
    // I thought Linq gave Select to list types?
    var toStringList = iList.Select(s => s.ToString());

    // The original foreach version:
    var outputList = new List<string>();
    foreach (var item in iList)
    {
        var itemToString = item.ToString();
        outputList.Add(itemToString);
    }
}

Upvotes: 0

Views: 964

Answers (1)

CodeCaster
CodeCaster

Reputation: 151674

Linq is a set of extension methods on everything that implements IEnumerable<T>.

The non-generic IList doesn't implement that interface, so Linq won't work on it.

Visual Studio 2019 Professional with ReSharper doesn't suggest Select for me:

enter image description here

Upvotes: 2

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