Question

我有一个用C＃编写的简单控制台应用程序。我希望能够检测箭头按键，这样我就可以让用户转向。如何使用控制台应用程序检测keydown / keyup事件？

我所有的谷歌搜索都导致了关于Windows窗体的信息。我没有GUI。这是一个控制台应用程序（通过串口控制机器人）。

我编写了处理这些事件的函数，但我不知道如何注册以实际接收事件：

  private void myKeyDown(object sender, KeyEventArgs e)
  {
      switch (e.KeyCode)
      {
          case Keys.Left:
                 ...
          case Keys.Right:
                 ...
          case Keys.Up:
                 ...
      }
  }

  private void myKeyUp(object sender, KeyEventArgs e)
  {
      ... pretty much the same as myKeyDown
  }

这可能是一个非常基本的问题，但我对C＃还不熟悉，而且我以前从未需要这样的输入。

更新：许多人建议我使用System.Console.ReadKey(true).Key。这没有用。我需要知道按键被释放的时刻，同时支持多个按键。此外，ReadKey是一个阻塞调用 - 这意味着程序将停止并等待按下一个键。

更新：似乎唯一可行的方法是使用Windows窗体。这很烦人，因为我无法在无头系统上使用它。要求表单GUI接收键盘输入是......愚蠢。

但无论如何，对于后代来说，这是我的解决方案。我在.sln中创建了一个新的Form项目：

    private void Form1_Load(object sender, EventArgs e)
    {
        try
        {
            this.KeyDown += new KeyEventHandler(Form1_KeyDown);
            this.KeyUp += new KeyEventHandler(Form1_KeyUp);
        }
        catch (Exception exc)
        {
            ...
        }
    }

    void Form1_KeyDown(object sender, KeyEventArgs e)
    {
        switch (e.KeyCode)
        {
            // handle up/down/left/right
            case Keys.Up:
            case Keys.Left:
            case Keys.Right:
            case Keys.Down:
            default: return;  // ignore other keys
        }
    }

    private void Form1_KeyUp(object sender, KeyEventArgs e)
    {
        // undo what was done by KeyDown
    }

请注意，如果您按住某个键，KeyDown将被多次调用，而KeyUp只会被调用一次（当您释放它时）。所以你需要优雅地处理重复的KeyDown调用。

Answer 1

现在有点晚了，但是这里是如何在控制台应用程序中访问键盘状态。

请注意，它不是所有托管代码，因为它需要从User32.dll导入GetKeyState。

/// <summary>
/// Codes representing keyboard keys.
/// </summary>
/// <remarks>
/// Key code documentation:
/// http://msdn.microsoft.com/en-us/library/dd375731%28v=VS.85%29.aspx
/// </remarks>
internal enum KeyCode : int
{
    /// <summary>
    /// The left arrow key.
    /// </summary>
    Left = 0x25,

    /// <summary>
    /// The up arrow key.
    /// </summary>
    Up,

    /// <summary>
    /// The right arrow key.
    /// </summary>
    Right,

    /// <summary>
    /// The down arrow key.
    /// </summary>
    Down
}

/// <summary>
/// Provides keyboard access.
/// </summary>
internal static class NativeKeyboard
{
    /// <summary>
    /// A positional bit flag indicating the part of a key state denoting
    /// key pressed.
    /// </summary>
    private const int KeyPressed = 0x8000;

    /// <summary>
    /// Returns a value indicating if a given key is pressed.
    /// </summary>
    /// <param name="key">The key to check.</param>
    /// <returns>
    /// <c>true</c> if the key is pressed, otherwise <c>false</c>.
    /// </returns>
    public static bool IsKeyDown(KeyCode key)
    {
        return (GetKeyState((int)key) & KeyPressed) != 0;
    }

    /// <summary>
    /// Gets the key state of a key.
    /// </summary>
    /// <param name="key">Virtuak-key code for key.</param>
    /// <returns>The state of the key.</returns>
    [System.Runtime.InteropServices.DllImport("user32.dll")]
    private static extern short GetKeyState(int key);
}

Answer 2

var isUp = Console.ReadKey().Key == ConsoleKey.UpArrow;

或其他例子，仅适用于您的情况：

while (true)
{
   var ch = Console.ReadKey(false).Key;
   switch(ch)
   {
       case ConsoleKey.Escape:
          ShutdownRobot();
          return;
       case ConsoleKey.UpArrow:
          MoveRobotUp();
          break;
       case ConsoleKey.DownArrow:
          MoveRobotDown();
          break;
   }
}

Answer 3

System.Console.ReadKey(true).Key == ConsoleKey.UpArrow

你可以把它变成旋转，例如：

while(Running)
{
  DoStuff();
  System.Console.ReadKey(true).Key == ConsoleKey.UpArrow
  Thread.Sleep(1)
}

Answer 4

示例代码：

        ConsoleKeyInfo kb = Console.ReadKey();
        if (kb.Key == ConsoleKey.LeftArrow)
                Console.WriteLine("Left Arrow pressed");

Answer 5

你可以这样做

bool keyWasPressed = false;
if (consolekey.avalable)
{
keyvar = console.readkey(true);
keyWasPressed = true;
}
if(keyWasPressed)
{
//enter you code here using keyvar
}
else
{
//the commands that happen if you don't press anything
}

Answer 6

我有同样的问题，你和我在这里发现了一个使用任务的有趣帖子。原帖可以在这里找到： C# Console Application - How do I always read input from the console?

我必须通过Raspberry GPIO（使用单声道C＃）模拟PWM输出来测试LCD背光。我想用两个简单的键来改变占空比（上/下）和一个额外的键来停止程序。

我试过这个（变量）：

static ConsoleKeyInfo key = new ConsoleKeyInfo();
static int counter = 0;
static int duty = 5; // Starts in 50%

主程序：

static void Main(string[] args)
{
// cancellation by keyboard string
    CancellationTokenSource cts = new CancellationTokenSource();
    // thread that listens for keyboard input
    var kbTask = Task.Run(() =>
    {
        while (true)
        {
            key = Console.ReadKey(true);
            if (key.KeyChar == 'x' || key.KeyChar == 'X')
            {
                cts.Cancel();
                break;
            }
            else if (key.KeyChar == 'W' || key.KeyChar == 'w')
            {
                if (duty < 10)
                    duty++;
                //Console.WriteLine("\tIncrementa Ciclo");
                //mainAppState = StateMachineMainApp.State.TIMER;
                //break;
            }
            else if (key.KeyChar == 'S' || key.KeyChar == 's')
            {
                if (duty > 0)
                    duty--;
                //Console.WriteLine("\tDecrementa Ciclo");
                //mainAppState = StateMachineMainApp.State.TIMER;
                // break;
            }
        }
    });

    // thread that performs main work
    Task.Run(() => DoWork(), cts.Token);

    string OsVersion = Environment.OSVersion.ToString();
    Console.WriteLine("Sistema operativo: {0}", OsVersion);
    Console.WriteLine("Menú de Progama:");
    Console.WriteLine(" W. Aumentar ciclo útil");
    Console.WriteLine(" S. Disminuir ciclo útil");
    Console.WriteLine(" X. Salir del programa");

    Console.WriteLine();
    // keep Console running until cancellation token is invoked
    kbTask.Wait();
}

static void DoWork()
{
    while (true)
    {
        Thread.Sleep(50);
        if (counter < 10)
        {
            if (counter < duty)
                Console.Write("─");
                //Console.WriteLine(counter + " - ON");
            else
                Console.Write("_");
                //Console.WriteLine(counter + " - OFF");
            counter++;
        }
        else
        {
            counter = 0;
        }
    }
}

当需要增加占空比时，按“W”键使主任务改变占空比变量（占空比）;同样的事情用'S'键递减。按下“X”键时程序结束。

控制台应用程序的C＃箭头键输入

6 个答案: