控制台应用程序的C#箭头键输入

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).

我有编写函数来处理这些事件,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......愚蠢的.

但无论如何,对于子孙后代,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;

或另一个示例，仅针对您的情况：

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;
   }
}