如何设置默认输入值的.Net控制台应用程序？

问题描述

您如何设置在.NET控制台应用程序默认的输入值？

How can you set a default input value in a .net console app?

下面是一些虚幻的code：

Here is some make-believe code:

Console.Write("Enter weekly cost: ");
string input = Console.ReadLine("135"); // 135 is the default. The user can change or press enter to accept
decimal weeklyCost = decimal.Parse(input);

当然，我不希望它是这么简单。我打赌有做一些低层次，非托管的东西;我只是不知道怎么办。

Of course, I don't expect it to be this simple. I am betting on having to do some low-level, unmanaged stuff; I just don't know how.

我知道我可以代替任何输入的默认值。这不是我问。我想了解什么是参与实现我所描述的行为：为用户提供一个可编辑的默认。我也并不担心输入验证;我的问题没有任何关系这一点。

I know I can replace no input with the default. That's not what I am asking about. I am trying to LEARN what's involved in achieving the behavior I described: giving the user an editable default. I'm also not worried about input validation; my question has nothing to do with that.

推荐答案

我相信，你将不得不通过听每个按键preSS手动管理这样的：

I believe that you will have manage this manually by listening to each key press:

快速thown一起例如：

Quickly thown together example:

   // write the initial buffer
   char[] buffer = "Initial text".ToCharArray();
   Console.WriteLine(buffer);

   // ensure the cursor starts off on the line of the text by moving it up one line
   Console.SetCursorPosition(Console.CursorLeft + buffer.Length, Console.CursorTop - 1);

   // process the key presses in a loop until the user presses enter
   // (this might need to be a bit more sophisticated - what about escape?)
   ConsoleKeyInfo keyInfo = Console.ReadKey(true);
   while (keyInfo.Key != ConsoleKey.Enter)
   {

       switch (keyInfo.Key)
       {
            case ConsoleKey.LeftArrow:
                    ...
              // process the left key by moving the cursor position
              // need to keep track of the position in the buffer

         // if the user presses another key then update the text in our buffer
         // and draw the character on the screen

         // there are lots of cases that would need to be processed (backspace, delete etc)
       }
       keyInfo = Console.ReadKey(true);
   }

这是相当复杂 - 你必须继续确保光标不出去的范围和手动更新缓存

This is quite involved - you'll have to keep ensure the cursor doesn't go out of range and manually update your buffer.

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