Question

我现在开始使用C＃。我在解决讲师要求我做的问题时遇到了问题。下面是GUI。

http://i.share.pho.to/daa36a24_c.png

这是我所做的代码，但我没有设法编写下面提到的部分

      using System;
      using System.Collections.Generic;
      using System.ComponentModel;
      using System.Data;
      using System.Drawing;
      using System.Linq;
      using System.Text;
      using System.Windows.Forms;

      namespace WindowsFormsApplication1
       {
          public partial class Form1 : Form
          {
              public Form1()
              {
                  InitializeComponent();
              }

              private void button1_Click(object sender, EventArgs e)
              {
                  double num1;
                  double num2;
                  double answer;

                  num1 = double.Parse(textBox1.Text);
                  num2 = double.Parse(textBox2.Text);


                  textBox4.Text = Convert.ToString(answer);
              }
          }
      }

我需要加/减/多/除第一和第二个数字，以便产生 - ＆gt; （第一个数字+操作+第二个数字=答案）。

问题是我需要通过单击文本框上的+， - ，*，/符号来选择操作。我可以通过使用单选按钮等轻松完成，但我的讲师坚持这种格式。请协助编写“操作”选项。谢谢。

Answer 1

只要操作在listBox中，请使用：

using System;
  using System.Collections.Generic;
  using System.ComponentModel;
  using System.Data;
  using System.Drawing;
  using System.Linq;
  using System.Text;
  using System.Windows.Forms;

  namespace WindowsFormsApplication1
   {
      public partial class Form1 : Form
      {
          public Form1()
          {
              InitializeComponent();
          }

          private void button1_Click(object sender, EventArgs e)
          {
              double num1;
              double num2;
              double answer;
              num1 = double.Parse(textBox1.Text);
              num2 = double.Parse(textBox2.Text);
              if (listBox1.SelectedIndex == 0)
              {
              answer = num1 + num2
              }
              if (listBox1.SelectedIndex == 1)
              {
              answer = num1 - num2
              }
              if (listBox1.SelectedIndex == 2)
              {
              answer = num1 * num2
              }
              if (listBox1.SelectedIndex == 3)
              {
              answer = num1 / num2
              }
              textBox4.Text = Convert.ToString(answer);
          }
      }
  }

Answer 2

您使用列表框的OnIndexChanged事件来了解选择了哪个运算符。

这将允许您计算每次单击列表框。

请注意，在operatorListBox1_SelectedIndexChanged事件方法中，您使用sender（已点击的对象）来查找SelectedItem。将其转换为字符串（它是列表框中的对象），您的符号将出现。（没有双关语）

using System;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        private int firstNum = 2;
        private int secondNum = 4;
        private int answer;

        public Form2()
        {
            InitializeComponent();
            operatorListBox1.Items.Add("+");
            operatorListBox1.Items.Add("-");
            operatorListBox1.Items.Add("*");
            operatorListBox1.Items.Add("/");
            //this next line would go in your designer.cs file.  I put it here for completeness
            this.operatorListBox1.SelectedIndexChanged += new System.EventHandler(this.operatorListBox1_SelectedIndexChanged);
        }

        private void operatorListBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            calculateAnswer(((ListBox)sender).SelectedItem.ToString());
        }

        private void calculateAnswer(string sign)
        {
            switch (sign)
            {
                case "+":
                    answer = firstNum + secondNum;
                    break;
                case "-":
                    answer = firstNum - secondNum;
                    break;
                case "*":
                    answer = firstNum * secondNum;
                    break;
                case "/":
                    answer = firstNum / secondNum;
                    break;
            }
            textBox4.Text = firstNum + " " + sign + " " + secondNum + " = " + answer;
        }
    }
}

C＃多线计算

2 个答案: