Question

I was reading in MSDN that a List is thread safe when used as a public static type . However the following code snippet proves otherwise. I am trying to add and remove elements from the list but the remove method throws an error midway saying index out of bounds. What is going wrong here?

Is this a right implementation to check my theory. If not, can someone please suggest a better example.

class Program
{
    public static List<string> strlist = new List<string>();
    public static AutoResetEvent autoEvent = new AutoResetEvent(false);
    static void Main(string[] args)
    {

        strlist = new List<string>();
        new Thread(() => 
        {

            for(int i=0;i<10000000;i++)
            {
         strlist.Add("item1");
            }
            //Thread.Sleep(5000);
            autoEvent.Set();
        }).Start(); ;

        new Thread(() => {

         strlist.ForEach(e => strlist.Remove(e));

        }).Start();

        Console.WriteLine("Waiting");
        autoEvent.WaitOne();
        int ci = 0;

        strlist.ForEach(str => ci++);
        Console.WriteLine(ci.ToString() + " Done");
        Console.Read();


    }

}

Answer 1

I was reading in MSDN that a List is thread safe when used as a public static type.

That statement is not true. You probably are referring to this text:

Public static members of this type are thread safe.

That refers to members of the class List<T>. It does not refer to instances of the class List<T>.