Getting keyboard input for real-time console application

Question

I've been building an IDE using C# and only the console. To get keyboard input in real time (as opposed to a read–eval–print loop,) I have the following method to get keyboard input:

public static ConsoleKeyInfo[] GetInput()
{
    // A list of characters
    List<ConsoleKeyInfo> input = new List<ConsoleKeyInfo>();

    // Loop while keys are available or we hit 10 keys
    for (int i = 0; Console.KeyAvailable && i < 10; i++)
    {
        // Read a key (preventing it from being printed) 
        // and put it in the key list (if it's not in there yet)
        ConsoleKeyInfo info = Console.ReadKey(true);
        if (!input.Contains(info))
        {
            input.Add(info);
        }
    }

    // Use up any remaining key presses
    while (Console.KeyAvailable)
    {
        // Read a single key
        Console.ReadKey(true);
    }

    // Convert the list to an array and return
    return input.ToArray();
}

GetInput called once at the start of the main loop and the result is passed into objects that handle key presses:

ConsoleKeyInfo[] keysHit = ConEx.ConEx_Input.GetInput();
Program.Interpreter.Update(Program.Interpreter.CurMode, keysHit);
Program.WindowUI.Update(Program.Interpreter.CurMode, keysHit);
Program.WindowSideBar.Update(Program.Interpreter.CurMode, keysHit);

Inside an Update method:

for (int i = 0; i < keysHit.Length; i++)
{
    switch (keysHit[i].Key)
    {
        //Cycle through the pages
        case ConsoleKey.Home:
            //Do some stuff
            break;
        case ConsoleKey.End:
            //Do other stuff
            break;
    }
}

Is this a sub optimal solution for getting keyboard input? I'm very willing to breakout P/Invoke or a threaded solution if need be. I can't support an event handler based solution due to the tight control of sequence needed.

Edit: Nikita B's answer is marked as Accepted because it reduced the amount of ticks taken from ~60 to ~30. Thanks!

Answer 1

You could join the two loops. I think this way your intent will be clearer, and it's not like a few extra comparisons are going to cost you anything.

//return "IEnumerable<T>" if all you need to do is iterate over elements
public static IEnumerable<ConsoleKeyInfo> GetInput()
{
    //use "var" if return type is obvious from context
    //use "HashSet<T>" if you need a collection of unique items
    var input = new HashSet<ConsoleKeyInfo>();
    var keyCount = 0;
    while (Console.KeyAvailable)
    {
        var key = Console.ReadKey(true);
        //use constants instead of magic numbers
        if (++keyCount > MaxInputLength) continue;
        //no need to call "Contains", non-unique items will be dropped automatically
        input.Add(key);
    }
    //no need to convert anything
    return input;
}

But I have to question your design. Why do I have to input (and memorize?) a 10-key sequence where every key means something and the order is important? Sounds like a really poor user experience. I feel like it is not the way to go in modern applications, iddqd or not.

Edit: I forgot, that HashSet does not preserve insertion order. So if order is important, you should stick to List (your original approach).