键盘输入问题 [英] Keyboard input problem

问题描述

I'm new to C# and  I'm now doing scientific calculator assignment. Can you please help me from calculation from keyboard input in detail because my code doesn't work? I  want to know all about from keyboard input.Also I don't know how to make multiopreation like 2+6+9-6*5. Sorry if I've grammar wrongs. Thank you so much all.

我的尝试：

What I have tried:

private void Main_KeyPress(object sender, KeyPressEventArgs e)
       {
           if (e.KeyChar == Convert.ToChar(Keys.Escape))
           {
               txtDisplay.Clear();
           }
           if (e.KeyChar == Convert.ToChar(Keys.Back))
               btnBack_Click(sender, e);

           if ((txtDisplay.Text == "0") || eqClick == false)
           {
               switch (e.KeyChar.ToString())
               {
                   case "+":
                       btnPlus.PerformClick();
                       break;
                   case "-":
                       btnMinus.PerformClick();
                       break;
                   case "*":
                       btnMultiply.PerformClick();
                       break;
                   case "/":
                       btnDivide.PerformClick();
                       break;
                   case "=":
                       btnEqual.PerformClick();
                       break;
                   case ".":btnDot.PerformClick();
                       break;
               }

           }
       }

推荐答案

我讨厌说出来，但你做错了。



你有两个问题：首先是你在不需要的地方强迫点击事件 - 更好的解决方案是让您的click事件处理程序调用方法，然后从其他代码调用相同的方法。这将用户界面与处理代码分开，这意味着以后更容易更改。



第二个是你要做的不是真的要上班了。您举一个2 + 6 + 9-6 * 5作为多操作的示例，但您需要定义结果应该发生的事情：55或-13再进一步。

第一个结果是微不足道的：每次获得运算符时，都要先评估数据。所以你得到了

I hate to say it, but you are doing this all wrong.

You have two problems: the first is that you are "forcing" click events where you don't need to - a much better solution is to have your click event handlers call a method, and then call the same method from your other code. This separates the user interface from the processing code, which means it becomes a lot easier to change things later.

The second is that what you are trying to do is not really going to work. You give an example of "2+6+9-6*5" as a "multi-operation", but you would need to define what should happen as a result: 55, or -13 before you go any further.
The first result is trivial: each time you get an operator, you evaluate the data before it. So you get

2
2+          Evaluate: 2 == 2
2+6
2+6+        Evaluate: 2 + 6 == 8
  8+9
  8+9-      Evaluate: 8 + 9 == 17
   17-6
   17-6*    Evaluate: 17-6 == 11
     11*5
     11*5=  Evaluate: 11*5 == 55

但是对于第二个你不能这样做因为你需要包含运算符优先级：*比+更重要所以你必须先评估（6 * 5）然后再做其余的事情 - 这是一个更加复杂的负载。



我建议你看看其他计算器是如何工作的：不只是Calc.EXE，而是微软数学：从Microsoft官方下载中心下载Microsoft Mathematics 4.0 [ ^ ]并找出你的意思想要在乐之前实现到目前为止你已经完成了代码！

But for the second one your can't do that because you need to include operator precedence: "*" is "more important" than "+" so you have to evaluate (6*5) before you can do the rest - and that is a whole load more complicated.

What I'd suggest is that you have a look at how other calculators work: not just Calc.EXE, but Microsoft Mathematics as well: Download Microsoft Mathematics 4.0 from Official Microsoft Download Center[^] and work out what you want to achieve before leaping into code as you have done so far!

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