第一次学习C#，做了个简单的加减乘除计算器，只能实现两个因数的运算。
主要是练习下C#编程，和以前用过的VB差不多。与VB6不同的是，C#代码区分大小写。
Windows窗口程序主要也是由一些控件组成，响应响应的事件(event)，实现具体的功能。
1.效果图如下所示
2.代码如下所示
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace WindowsApplication1
{
public partial class Main : Form
{
public Main()
{
InitializeComponent();
}
private void Main_Load(object sender, EventArgs e)
{
}
private void txtInshu1_TextChanged(object sender, EventArgs e)
{
}
private void txtInshu1_KeyPress(object sender, KeyPressEventArgs e)
{
OnlyEnterNumber(sender, e);
}
//// <summary>
/// 只能输入数字（含负号小数点）
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
public static void OnlyEnterNumber(object sender, KeyPressEventArgs e)
{
if ((e.KeyChar < 48 || e.KeyChar > 57) && e.KeyChar != 8 && e.KeyChar != 13 && e.KeyChar != 45 && e.KeyChar != 46)
{
e.Handled = true;
}
// 输入为负号时，只能输入一次且只能输入一次
if (e.KeyChar == 45 && (((TextBox)sender).SelectionStart != 0 || ((TextBox)sender).Text.IndexOf("-") >= 0)) e.Handled = true;
if (e.KeyChar == 46 && ((TextBox)sender).Text.IndexOf(".") >= 0) e.Handled = true;
}
/*
* 参数：d表示要四舍五入的数；i表示要保留的小数点后位数。
* 正负数都四舍五入，适合数据统计的显示
*/
double Round(double d, int i)
{
if (d >= 0)
{
d += 5 * Math.Pow(10, -(i + 1));
}
else
{
d += -5 * Math.Pow(10, -(i + 1));
}
string str = d.ToString();
string[] strs = str.Split('.');
int idot = str.IndexOf('.');
string prestr = strs[0];
string poststr = strs[1];
if (poststr.Length > i)
{
poststr = str.Substring(idot + 1, i);
}
string strd = prestr + "." + poststr;
d = Double.Parse(strd);
return d;
}
private void txtInshu2_TextChanged(object sender, EventArgs e)
{
}
private void txtInshu2_KeyPress_1(object sender, KeyPressEventArgs e)
{
OnlyEnterNumber(sender, e);
}
private void btnJisuan_Click(object sender, EventArgs e)
{
if (txtInshu1.Text == "") {
MessageBox.Show("因数1不能为空！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
if (txtInshu2.Text == "")
{
MessageBox.Show("因数2不能为空！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
double inshu1 = Convert.ToDouble(txtInshu1.Text);
double inshu2 = Convert.ToDouble(txtInshu2.Text);
double result = 0.0;
if (radioBtnJia.Checked) {
result = inshu1 + inshu2;
}
if (radioBtnJian.Checked)
{
result = inshu1 - inshu2;
}
if (radioBtnCheng.Checked)
{
result = inshu1 * inshu2;
}
if (radioBtnChu.Checked)
{
if (0 == inshu2)
{
MessageBox.Show("因数2做除数不能为0！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
result = inshu1 / inshu2;
result = Round(result, 6);
}
txtResult.Text = Convert.ToString(result);
}
}
}
