输入字符串的不正确的格式

问题描述

我是新的C＃，我在Java的一些基本知识，但我不能让这个code才能正常运行。

I'm new with C#, I have some basic knowledge in Java but I can't get this code to run properly.

这只是一个基本的计算器，但是当我运行程序VS2008给了我这个错误：

It's just a basic calculator, but when I run the program VS2008 gives me this error:

我几乎没有使用JSwing相同的程序，但在java中它完美地工作。

I did almost the same program but in java using JSwing and it worked perfectly.

下面是C＃的形式：

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 calculadorac
{
    public partial class Form1 : Form
    {

    int a, b, c;
    String resultado;

    public Form1()
    {
        InitializeComponent();
        a = Int32.Parse(textBox1.Text);
        b = Int32.Parse(textBox2.Text);
    }

    private void button1_Click(object sender, EventArgs e)
    {
        add();
        result();
    }

    private void button2_Click(object sender, EventArgs e)
    {
        substract();
        result();
    }

    private void button3_Click(object sender, EventArgs e)
    {
        clear();
    }

    private void add()
    {
        c = a + b;
        resultado = Convert.ToString(c);
    }

    private void substract()
    {
        c = a - b;
        resultado = Convert.ToString(c);
    }

    private void result()
    {
        label1.Text = resultado;
    }

    private void clear()
    {
        label1.Text = "";
        textBox1.Text = "";
        textBox2.Text = "";
    }
}

可以是什么问题？有没有办法解决这个问题的方法吗？

What can be the problem? Is there a way to solve it?

PS：我也试过

a = Convert.ToInt32(textBox1.text);
b = Convert.ToInt32(textBox2.text);

和它没有工作。

推荐答案

该错误是指字符串你试图解析一个整数实际上并不包含有效的整数。

The error means that the string you're trying to parse an integer from doesn't actually contain a valid integer.

这是非常不可能的文本框将包含时立即被创建的形式有效的整数 - 这就是你得到的整数值。它将使更多的意义更新 A 和 B 在按钮的点击事件（在你以同样的方式在构造函数）。此外，检查出的 Int.TryParse 法 - 这是容易得多，如果该字符串可能不实际包含的整数使用 - 它不抛出一个异常，以便更容易恢复从

It's extremely unlikely that the text boxes will contain a valid integer immediately when the form is created - which is where you're getting the integer values. It would make much more sense to update a and b in the button click events (in the same way that you are in the constructor). Also, check out the Int.TryParse method - it's much easier to use if the string might not actually contain an integer - it doesn't throw an exception so it's easier to recover from.

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