How to Get a Combination of Keys in C#

Capture combination key event in a Windows Forms application

Handle the KeyDown event and have something like:

if (e.Modifiers == Keys.Shift && e.KeyCode == Keys.Up)
{
    MessageBox.Show("My message");
}

The event handler has to be on the Main Form and you need to set the KeyPreview property to true. This can be done in design mode from the properties dialog.

get combination from a list of key-values

Quick & dirty but you may polish this method. The result list contains expected result:

Usage:

var dict = new Dictionary<String, List<String>>() { 
    {"1",new List<String>(){"a", "b"}},
    {"2",new List<String>(){"c", "d", "e"}},
    {"3",new List<String>(){"f", "g"}},
};

var collections = dict.Select(kvp => kvp.Value).ToArray();            
var result = new List<string>(); 
GetNextProduct(collections, 0, String.Empty, result);

Method that produces the result:

private static void GetNextProduct(IEnumerable<string>[] collections, int collectionIndex, string currentProduct, IList<string> results)
{
    var currentList = collections[collectionIndex];
    bool isLast = collections.Length == collectionIndex + 1;
    foreach (var s in currentList)
    {
        if (isLast) results.Add(currentProduct + s);
        else GetNextProduct(collections, collectionIndex + 1, currentProduct + s, results);
    }
}

Detect key combination being pressed in C# console app

If you capture the ConsoleKeyInfo, you will get additional information, including the Modifiers keys. You can query this to see if the Control key was pressed:

ConsoleKey key;

do
{
    while (!Console.KeyAvailable)
    {
        // Do something, but don't read key here
    }

    // Key is available - read it
    var keyInfo = Console.ReadKey(true);
    key = keyInfo.Key;

    if ((keyInfo.Modifiers & ConsoleModifiers.Control) != 0)
    {
        Console.Write("Ctrl + ");
    }
    if (key == ConsoleKey.NumPad1)
    {                    
        Console.WriteLine(ConsoleKey.NumPad1.ToString());
    }
    else if (key == ConsoleKey.NumPad2)
    {
        Console.WriteLine(ConsoleKey.NumPad2.ToString());
    }

} while (key != ConsoleKey.Escape);

Key combination shortcut

After a long search and experiment, a solution has finally been found
https://stackoverflow.com/a/12676910/8152725

How to calculate keys combination in c#

Console.Write((int) (Keys.Alt | Keys.F))

Or more basic:

1000000000000000000 OR 1000110 = 1000000000001000110

Display all keys combination

I believe you are looking for GetKeyboardState function. I will give you status of all virtual keys in one call. The GetAsyncKeyState function is better used to check if the user pressed a key or not.

As an exercise, I wrote the following to demonstrate the GetAsyncKeyState API call:

using System;
using System.Runtime.InteropServices;
using System.Threading;

namespace s26244308
{
    class Program
    {
        static void Main(string[] args)
        {
            bool keepGoing = true;

            while (keepGoing)
            {
                int wasItPressed = SysWin32.GetAsyncKeyState(SysWin32.VK_ESCAPE);
                if (wasItPressed != 0)
                {
                    keepGoing = false;  // stop
                    continue;
                }

                // for this sample: just loop a few letters
                for (int x = 0x41; x <= 0x4A; x++)
                {
                    int letterPressed = SysWin32.GetAsyncKeyState(x);
                    if (letterPressed != 0)
                    {
                        // now check for a few other keys
                        int shiftAction = SysWin32.GetAsyncKeyState(SysWin32.VK_SHIFT);
                        int ctrlAction = SysWin32.GetAsyncKeyState(SysWin32.VK_CONTROL);
                        int altAction = SysWin32.GetAsyncKeyState(SysWin32.VK_MENU);

                        // format my output
                        string letter = string.Format("Letter: {0} ({1})", Convert.ToChar(x), KeyAction(letterPressed));
                        string shift = string.Format("Shift: {0}", KeyAction(shiftAction));
                        string ctrl = string.Format("Control: {0}", KeyAction(ctrlAction));
                        string alt = string.Format("Alt: {0}", KeyAction(altAction));

                        Console.WriteLine("{0,-20}{1,-18}{2,-18}{3,-18}", letter, shift, ctrl, alt);
                        break;
                    }
                }
                Thread.Sleep(10);
            }

            Console.WriteLine("-- Press Any Key to Continue --");
            Console.ReadLine();
        }

        private static string KeyAction(int pressed)
        {
            if (pressed == 0)
                return "Up";

            // check LSB
            if (IsBitSet(pressed, 0))
                return "Pressed";

            // checked MSB
            if (IsBitSet(pressed, 15))
                return "Down";

            return Convert.ToString(pressed, 2);
        }
        private static bool IsBitSet(int b, int pos)
        {
            return (b & (1 << pos)) != 0;
        }
    }

    class SysWin32
    {
        public const int VK_ESCAPE = 0x1B;
        public const int VK_SHIFT = 0x10;
        public const int VK_CONTROL = 0x11;
        public const int VK_MENU = 0x12;

        [DllImport("user32.dll")]
        public static extern int GetAsyncKeyState(Int32 i);
    }

}

here is the console output:

---

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