Last 3 sent messages against the newest while saving only the last 3 newest messages?

Currently I have a simple class for users, like the follow:

public class Users
{
    public int ID { get; set; }
    public string Name { get; set; }
    public Groups Access { get; set; }
    public IPAddress IP { get; set; }
    public bool IsProtected { get; set; }
    public bool IsInvisible { get; set; }
}

Now I would like to store the user last 3 sent messages and be able to compare if user new last message matchs with any of the previous 3 stores messages and if not remove the oldest message from the list and add the new one.

I was initially thinking of simple using a list of strings and go for something like this:

bool msg_match = user.LastMessages.Any(x => String.Equals(x, msg, StringComparison.OrdinalIgnoreCase));
if (msg_match)
{
    // punish user
    user.LastMessages.Clear();
}
else
{
    // some way to remove oldest message and leave only the 3 newest messages
    user.LastMessages.Add(mensagem);
}

The above method do work but I am a bit clueless on how to pick the oldest message to be removed resulting in the last the newest messages and also a not sure if this method would be ok or if there is a better way to approach this 开发者_如何学编程?

PS: My title sounds rather confusing I think if you have a better idea for the title let me know or change it pls.

You could store the messages in a LinkedList<string>. This would make it simple to do you check:

bool msg_match = user.LastMessages.Any(x => String.Equals(x, msg, StringComparison.OrdinalIgnoreCase));
if (msg_match)
{
    // punish user
    user.LastMessages.Clear();
}
else
{
    // some way to remove oldest message and leave only the 3 newest messages
    user.LastMessages.AddFirst(mensagem);
    if (user.LastMessages.Count > 3)
        user.LastMessages.RemoveLast();
}