在控制台应用程序中阅读按键 [英] Reading Key Press in Console App

问题描述

我正在编写一个小应用程序，它将等待按键，然后根据所按的按键执行操作.例如，如果没有按键，它将继续等待；如果按键1，则将执行操作1；或者如果按键2，则将执行操作2.例如，href ="https://stackoverflow.com/questions/5891538/listen-for-key-press-in-net-console-app">一个.到目前为止，我有以下代码.

I'm writing a small application which will wait for a key press, then perform an action based on what key is pressed. For example, if no key is pressed, it will just continue waiting, if key 1 is pressed, it will perform action 1, or if key 2 is pressed it will perform action 2. I have found several helpful posts so far, this one being an example. From this, I have the following code so far.

do
{
    while (!Console.KeyAvailable)
    {
        if (Console.ReadKey(true).Key == ConsoleKey.NumPad1)
        {
            Console.WriteLine(ConsoleKey.NumPad1.ToString());
        }
        if (Console.ReadKey(true).Key == ConsoleKey.NumPad2)
        {
            Console.WriteLine(ConsoleKey.NumPad1.ToString());
        }
    }

} while (Console.ReadKey(true).Key != ConsoleKey.Escape);

这可能有两个问题，您可能已经猜到了.

There's a couple of issue with this, which you may have guessed already.

1) 使用ReadKey检测哪个键被按下会导致暂时的暂停，这意味着必须按下该键.我真的需要找到一种方法来避免这种情况.可能使用KeyAvailable，但是我不确定如何使用它来检测按下了哪个键-有什么想法吗?

1) Using the ReadKey to detect which key is pressed results in a temporary pause, meaning the key will have to be pressed. I really need to find a way to avoid this. Possibly using KeyAvailable, but I'm not sure how you can use this to detect which key has been pressed - any ideas?

2) 由于某些原因，Escape键不会退出应用程序.如果我删除了if语句，就可以了，但是按上述方式运行代码并不能让我使用指定的键退出应用程序-有什么想法吗?

2) For some reason, the Escape key does not escape out of the application. It does if I remove the if statements, however running the code as is above does not let me exit the application using the designated key - any ideas?

推荐答案

该行为的原因很简单:

只要没有按键按下，您就可以进入嵌套循环. 在内部，您正在等待密钥并读取它-因此，再次没有可用的密钥. 即使您按Escape键，您仍然位于嵌套循环中，永远也不会脱离它.

You get inside the nested loop as long as there is no key pressed. Inside you are waiting for a key and read it - So again no key is available. even if you press escape, you are still inside the nested loop and never get out of it.

您应该做的是循环直到找到可用的密钥，然后读取并检查其值:

What you should of done is loop until you have a key available, then read it and check its value:

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

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

    if (key == ConsoleKey.NumPad1)
    {
        Console.WriteLine(ConsoleKey.NumPad1.ToString());
    }
    else if (key == ConsoleKey.NumPad2)
    {
        Console.WriteLine(ConsoleKey.NumPad1.ToString());
    }

} while (key != ConsoleKey.Escape);

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