刚学C#，请各位老师帮忙看看这段代码....

Question

因为刚学C#，想做个计算器，在做到加法运算时想点击“+”进行加法运算，可是想了很多办法都不行。主要是想在textbox1里输入完数字后，一点“+”号将textbox1里的数字传到textbox2中显示，然后继续在textbox1中输入，在textbox2中显示结果，有点累加的意思。就是不论textbox1里输入多少次始终在textbox2中累加结果，不知道有什么方法或是下面的代码应该怎么改。请教我一下：谢谢！（不知道用FOR循环行不行，太晚还没试.呵呵!）
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;namespace calculator
{
    public partial class Form1 : Form
    {
        public double T1_value;
        public double T2_value;
        public double N_num1 = 0;
        public double N_num2 = 0;
        public double Sum;
        
        public Form1()
        {
            InitializeComponent();
        }        private void button1_Click(object sender, EventArgs e)
        {
            textBox1.Text += "1"; ;
        }        private void button2_Click(object sender, EventArgs e)
        {
            textBox1.Text += "2";
        }
        private void button3_Click_1(object sender, EventArgs e)
        {
            textBox1.Text += "3";
        }        private void button4_Click(object sender, EventArgs e)
        {
            textBox1.Text += "4";
        }        private void button5_Click(object sender, EventArgs e)
        {
            textBox1.Text += "5";
        }        private void button6_Click(object sender, EventArgs e)
        {
            textBox1.Text += "6";
        }        private void button7_Click(object sender, EventArgs e)
        {
            textBox1.Text += "7";
        }        private void button9_Click(object sender, EventArgs e)
        {
            textBox1.Text += "8";
        }        private void button8_Click(object sender, EventArgs e)
        {
            textBox1.Text += "9";
        }        private void button10_Click(object sender, EventArgs e)
        {
            textBox1.Text += "0";
        }        private void button11_Click(object sender, EventArgs e)//加法运算
        {                do
                {
                   if (textBox1.Text != "")
                        {
                            N_num1 = Convert.ToDouble(textBox1.Text);
                            N_num2 = Convert.ToDouble(textBox2.Text);
                            Sum = N_num1 + N_num2;
                            textBox2.Text = Sum.ToString();
                            textBox1.Text = "";
                           
                        }
 
                } while (textBox2.Text=="");
               
         
        }

Answer 1

private void button11_Click(object sender, EventArgs e)//加法运算
        {         textBox2.Text =Convert.ToDouble（textBox2.Text ） +  Convert.ToDouble(textBox1.Text);                           
     textBox1.Text=“”；
        }

Answer 2

private void button11_Click(object sender, EventArgs e)//加法运算
        {
                   if (!string.IsNullOrEmpty(textBox1.Text))
                        {
                            if (double.TryParse(textBox1.Text, out N_num1) &&
                            double.TryParse(textBox2.Text, out N_num2))
                            {
                              Sum = N_num1 + N_num2;
                              textBox2.Text = Sum.ToString();
                              textBox1.Text = "";
                            }
                           
                        }
        }
大概看了一下,不知道你要的是不是这个意思.没开VS写,可能有点小错.

Answer 3

1楼和2楼两位的方法我都试了，还是不行，一楼的方式我用过，不过显示错误，在我的那段代码中一到这条语句就报错：N_num2 = Convert.ToDouble(textBox2.Text);好像是类型转换的时textbox2.Text没有赋值的问题。

Answer 4

private void button11_Click(object sender, EventArgs e)//加法运算
        {
 if(textBox2.Text.Equals(""))
         {
    textBox2.Text=0;
 }
 if(textBox1.Text.Equals(""))
         {
    textBox1.Text=0;
 }
         textBox2.Text =Convert.ToDouble（textBox2.Text ） +  Convert.ToDouble(textBox1.Text);                             textBox1.Text=""；
         
        }

Answer 5

button11_Click内有
textBox2.Text = Sum.ToString();
textBox1.Text = "";
程序有可能出现假死,小心了

Answer 6

button11_Click内有
textBox1.Text += "1"; ;(这个地方是一个分号吧！)
if (textBox1.Text != "")
{
  N_num1 = Convert.ToDouble(textBox1.Text);
  N_num2 = Convert.ToDouble(textBox2.Text);
  Sum = N_num1 + N_num2;
  textBox2.Text = Sum.ToString(); （这个也在button11_Click，会有冲突出错吧）
 textBox1.Text = "";
}

Answer 7

除错,加入异常判断.
Convert.ToDouble(textBox2.Text);
当转换失败时会抛出异常的.
所以需要在前面判断是否能够转换为Double

Answer 8

textBox2.Text = Sum(ToString());
textBox1.Text = "";

Answer 9

private void button11_Click(object sender, EventArgs e)//加法运算
{            if (double.TryParse(TextBox1.text))
            {
                if (double.TryParse(TextBox2.text))
                {
                    TextBox2.text = double.Parse(TextBox1.text) + double.Parse(TextBox2.text);
                }
                else
                {
                    TextBox2.text = double.Parse(TextBox1.text);
                }
            } 
}

Answer 10

用double.TryParse()判断比较好，这样就不会容易有异常
private void button11_Click(object sender, EventArgs e)//加法运算
        {
                   if (!string.IsNullOrEmpty(textBox1.Text))
                        {
                            if (double.TryParse(textBox1.Text, out N_num1) &&
                            double.TryParse(textBox2.Text, out N_num2))
                            {
                              Sum = N_num1 + N_num2;
                              textBox2.Text = Sum.ToString();
                              textBox1.Text = "";
                            }
                           
                        }
        }

Answer 11

已解决完的代码：不知道哪位老师看看能不能将代码再简便些
        private void button11_Click(object sender, EventArgs e)//加法运算
        {
            do
            {
                if (textBox1.Text != "")
                {
                    N_num1 = Convert.ToDouble(textBox1.Text);
                    if (N_num2 == 0)
                    {
                        N_num2 += N_num1;
                        textBox2.Text = N_num2.ToString();
                    }
                    else
                    {
                        N_num2 = Convert.ToDouble(textBox2.Text);
                        Sum = N_num1 + N_num2;
                        textBox2.Text = Sum.ToString();
                    }
                    textBox1.Text = "";
                }
                else
                {
                    textBox1.Text = Convert.ToString("0");
                    textBox2.Text = Convert.ToString("0");
                    textBox1.Text = "";
                }            } while (textBox2.Text == "");        }

Answer 12

你的+是进行的string类型操作 需要将string转换成int

Answer 13

新手路过。
if (textBox1.Text =="")
            {
                MessageBox.Show(" textBox1.Text is null!");
            }
            else
            { 
                N_num1 = Convert.ToDouble(textBox1.Text);                if (textBox2.Text == "")
                {
                    sum += N_num1;
                    textBox2.Text = sum.ToString(); 
                    textBox1.Text = "";
                }
                else
                {
                    N_num2 = Convert.ToDouble(textBox2 .Text );
                    sum = N_num1 + N_num2;
                    textBox2.Text = sum.ToString();
                    textBox1.Text = "";
                }
            }

Answer 14

private void button11_Click(object sender, EventArgs e)//加法运算
        {         textBox2.Text =Convert.ToDouble（textBox2.Text.Trim()==""?"0":textBox2.Text.Trim() ） +  Convert.ToDouble(textBox1.Text);                           
     textBox1.Text=“”；
        }
记得判断textbox2超过double的有效长度没。用tryPrase