“System.FormatException”类型的未经处理的异常在 mscorlib.dll 中发生
其他信息: 输入字符串的格式不正确。
为什么doubleparse那里错了?
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace 算数练习
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
int a, b;
int x,y;
string op;
int result;
Random rnd = new Random();
private void Form1_Load(object sender, EventArgs e)
{
}
private void lalresult_Click(object sender, EventArgs e)
{
}
private void lalA_Click(object sender, EventArgs e)
{
}
private void rabtn100add_CheckedChanged(object sender, EventArgs e)
{
x = 99;
y = 2;
}
private void rabtn10mul_CheckedChanged(object sender, EventArgs e)
{
x = 9;
y = 4;
}
private void timexchange_Tick(object sender, EventArgs e)
{
a = rnd.Next(x) + 1;
b = rnd.Next(x) + 1;
int c = rnd.Next(y);
switch (c)
{
case 0: op = "+"; result = a + b; break;
case 1: op = "-"; result = a - b; break;
case 2: op = "*"; result = a * b; break;
case 3: op = "/"; result = a / b; break;
}
lalA.Text = a.ToString();
lalop.Text = op;
lalB.Text = b.ToString();
txtAnswer.Text = "";
string str = txtAnswer.Text;
double d = double.Parse(str);//这里错了,怎么改?
string disp = "" + a + op + b + "=" + str + " ";
if (d == result)
disp += "√";
else
disp += "×";
listBox1.Items.Add(disp);
}
private void btnfast_Click(object sender, EventArgs e)
{
timexchange.Interval -= 500;
}
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
string str = txtAnswer.Text;
double d = double.Parse(str);
string disp = "" + a + op + b + "=" + str + " ";
if (d == result)
disp += "√";
else
disp += "×";
listBox1.Items.Add(disp);
}
private void btnslow_Click(object sender, EventArgs e)
{
timexchange.Interval += 500;
}
private void rabtn10add_CheckedChanged(object sender, EventArgs e)
{
x = 9;
y = 2;
}
}
}