[c#] How to initialize a list of strings (List<string>) with many string values

How is it possible to initialize (with a C# initializer) a list of strings? I have tried with the example below but it's not working.

List<string> optionList = new List<string>
{
    "AdditionalCardPersonAddressType","AutomaticRaiseCreditLimit","CardDeliveryTimeWeekDay"
}();

Just remove () at the end.

List<string> optionList = new List<string>
            { "AdditionalCardPersonAdressType", /* rest of elements */ };

List<string> animals= new List<string>();
animals.Add("dog");
animals.Add("tiger");

Your function is just fine but isn't working because you put the () after the last }. If you move the () to the top just next to new List<string>() the error stops.

Sample below:

List<string> optionList = new List<string>()
{
    "AdditionalCardPersonAdressType","AutomaticRaiseCreditLimit","CardDeliveryTimeWeekDay"
};

You haven't really asked a question, but the code should be

List<string> optionList = new List<string> { "string1", "string2", ..., "stringN"}; 

i.e. no trailing () after the list.

One really cool feature is that list initializer works just fine with custom classes too: you have just to implement the IEnumerable interface and have a method called Add.

So for example if you have a custom class like this:

class MyCustomCollection : System.Collections.IEnumerable
{
    List<string> _items = new List<string>();

    public void Add(string item)
    {
        _items.Add(item);
    }

    public IEnumerator GetEnumerator()
    {
        return _items.GetEnumerator();
    }
}

this will work:

var myTestCollection = new MyCustomCollection()
{
    "item1",
    "item2"
}

Move round brackets like this:

var optionList = new List<string>(){"AdditionalCardPersonAdressType","AutomaticRaiseCreditLimit","CardDeliveryTimeWeekDay"};

List<string> facts = new List<string>() {
        "Coronavirus (COVID-19) is an illness caused by a virus that can spread from personto person.",
        "The virus that causes COVID-19 is a new coronavirus that has spread throughout the world. ",
        "COVID-19 symptoms can range from mild (or no symptoms) to severe illness",
        "Stay home if you are sick,except to get medical care.",
        "Avoid public transportation,ride-sharing, or taxis",
        "If you need medical attention,call ahead"
        };

var animals = new List<string> { "bird", "dog" };
List<string> animals= new List<string> { "bird", "dog" };

Above two are the shortest ways, please see https://www.dotnetperls.com/list

This is how you initialize and also you can use List.Add() in case you want to make it more dynamic.

List<string> optionList = new List<string> {"AdditionalCardPersonAdressType"};
optionList.Add("AutomaticRaiseCreditLimit");
optionList.Add("CardDeliveryTimeWeekDay");

In this way, if you are taking values in from IO, you can add it to a dynamically allocated list.

This is how you would do it.

List <string> list1 = new List <string>();

Do Not Forget to add

using System.Collections.Generic;