C# Notice when a key is pressed

Question

Hello I am doing a program that will notice when a specific key is pressed and write an specific letter where the person is writing. But i have a problem, it is that i not want to be needing to have the program as the "maked one". instead I do want it to trigger and write out a spesifick letter or text where the user is writing as the user is pressing the key...

I hope you understand and thanks for all help

here's the code i get so far:

        static void Main(string[] args)
    {

        while (true)
        {
            ConsoleKeyInfo cki;
            cki = Console.ReadKey();
            Console.WriteLine(cki.Key.ToString());

            if (cki.Key.ToString() == "A" && (cki.Modifiers & ConsoleModifiers.Control) != 0)
            {
                System.Threading.Thread.Sleep(400);
                TSendKeys.SendWait("ø");
            }
        }
    }

Answer 1

But i have a problem, it is that i not want to be needing to have the program as the "maked one". instead I do want it to trigger and write out a spesifick letter or text where the user is writing as the user is pressing the key...

Reading this I think you're talking about Windows Hooks . This means that user prints something in another application, let's say Word , but you're able to catch that key (even if it wasn't pressed in your app). If this is what you actually want, this CodeProject article is what you need.

Answer 2

您可能必须使用一个钩子， 本文将详细介绍如何执行此操作。

Answer 3

One approach is to emulate the behavior of Console.ReadLine, while in actuality reading and outputting each character separately. When reading special sequences, such as CTRL+A, the behavior can be intercepted and character inserted. A basic implementation is below.

private static string EmulateReadLine()
{
    StringBuilder sb = new StringBuilder();
    int pos = 0;
    Action<int> SetPosition = (i) =>
        {
            i = Math.Max(0, Math.Min(sb.Length, i));
            pos = i;
            Console.CursorLeft = i;
        };
    Action<char, int> SetLastCharacter = (c, offset) =>
        {
            Console.CursorLeft = sb.Length + offset;
            Console.Write(c);
            Console.CursorLeft = pos;
        };
    ConsoleKeyInfo key;
    while ((key = Console.ReadKey(true)).Key != ConsoleKey.Enter)
    {
        int length = sb.Length;
        if (key.Key == ConsoleKey.LeftArrow)
        {
            SetPosition(pos - 1);
        }
        else if (key.Key == ConsoleKey.RightArrow)
        {
            SetPosition(pos + 1);
        }
        else if (key.Key == ConsoleKey.Backspace)
        {
            if (pos == 0) continue;
            sb.Remove(pos - 1, 1);
            SetPosition(pos - 1);
        }
        else if (key.Key == ConsoleKey.Delete)
        {
            if (pos == sb.Length) continue;
            sb.Remove(pos, 1);
        }
        else if (key.Key == ConsoleKey.Home)
            SetPosition(0);
        else if (key.Key == ConsoleKey.End)
            SetPosition(int.MaxValue);
        else if (key.Key == ConsoleKey.Escape)
        {
            SetPosition(0);
            sb.Clear();
        }
        // CUSTOM LOGIC FOR CTRL+A
        else if (key.Key == ConsoleKey.A &&
            (key.Modifiers & ConsoleModifiers.Control) != 0)
        {
            string stringtoinsert = "^";
            sb.Insert(pos, stringtoinsert);
            SetPosition(pos + stringtoinsert.Length);
        }
        else if (key.KeyChar != '\u0000') // keys that input text
        {
            sb.Insert(pos, key.KeyChar);
            SetPosition(pos + 1);
        }

        // replace entire line with value of current input string
        Console.CursorLeft = 0;
        Console.Write(sb.ToString());
        Console.Write(new string(' ', Math.Max(0, length - sb.Length)));
        Console.CursorLeft = pos;
    }

    Console.WriteLine();
    return sb.ToString();
}

To drive:

static void Main(string[] args)
{
    string input = EmulateReadLine();
    Console.WriteLine("Entered {0}", input);
}

When entering the line, pressing CTRL+A will insert the "^" character. Arrow keys, Escape, Home, and End should function as they do normally for Console.ReadLine. (To simplify the code, the custom insertion logic is hardwired in.)