First design the interface, draw so many buttons, and name each button, and then double-click the button to add the corresponding event, such as pressing a number, add a number to textbox.text.
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 Calculator
{
public partial class Form1 : Form
{
double a = 0;//Calculation result
double b = 0;//The first operand
double h = 0; // second operand
string d;//Operation symbol
bool c=false;//Empty the textbox after pressing the operator
public Form1()
{
InitializeComponent();
}
private void button3_Click(object sender, EventArgs e)
{
}
//press 0
private void button10_Click(object sender, EventArgs e)
{
if(c==true)
{
c = false;
textBox1.Text = "";
}
textBox1.Text += "0";
if(d=="/"&&textBox1.Text=="0")
{
textBox1.Clear();
MessageBox.Show("Divisor cannot be 0!");
}
}
//press 1
private void button1_Click(object sender, EventArgs e)
{
if (c == true)
{
c = false;
textBox1.Text = "";
}
textBox1.Text += "1";
}
//press 2
private void button2_Click(object sender, EventArgs e)
{
if (c == true)
{
c = false;
textBox1.Text = "";
}
textBox1.Text += "2";
}
//press 3
private void button3_Click_1(object sender, EventArgs e)
{
if (c == true)
{
c = false;
textBox1.Text = "";
}
textBox1.Text += "3";
}
//press 4
private void button4_Click(object sender, EventArgs e)
{
if (c == true)
{
c = false;
textBox1.Text = "";
}
textBox1.Text += "4";
}
//press 5
private void button5_Click(object sender, EventArgs e)
{
if (c == true)
{
c = false;
textBox1.Text = "";
}
textBox1.Text += "5";
}
//press 6
private void button6_Click(object sender, EventArgs e)
{
if (c == true)
{
c = false;
textBox1.Text = "";
}
textBox1.Text += "6";
}
//press 7
private void button7_Click(object sender, EventArgs e)
{
if (c == true)
{
c = false;
textBox1.Text = "";
}
textBox1.Text += "7";
}
//press 8
private void button8_Click(object sender, EventArgs e)
{
if (c == true)
{
c = false;
textBox1.Text = "";
}
textBox1.Text += "8";
}
//press 9
private void button9_Click(object sender, EventArgs e)
{
if (c == true)
{
c = false;
textBox1.Text = "";
}
textBox1.Text += "9";
}
//press.
private void button11_Click(object sender, EventArgs e)
{
if (c == true)
{
c = false;
textBox1.Text = "";
}
if(!textBox1.Text.Contains("."))
textBox1.Text += ".";
}
//press +
private void button17_Click(object sender, EventArgs e)
{
c = true;
h = double.Parse(textBox1.Text);
switch (d)
{
case "+":
b = b + h;
break;
case "-":
b = b - h;
break;
case "*":
b = b * h;
break;
case "/":
b = b / h;
break;
case "%":
b = b % h;
break;
default:
b = h;
break;
}
d = "+";
//if(double.TryParse(textBox1.Text,out b)==true)
//{
// b = double.Parse(textBox1.Text);
//}
//else
//{
// MessageBox.Show("Please enter the correct number!");
// textBox1.Text = "";
//}
}
//press-
private void button16_Click(object sender, EventArgs e)
{
c = true;
h = double.Parse(textBox1.Text);
switch (d)
{
case "+":
b = b + h;
break;
case "-":
b = b - h;
break;
case "*":
b = b * h;
break;
case "/":
b = b / h;
break;
case "%":
b = b % h;
break;
default:
b = h;
break;
}
d = "-";
//if (double.TryParse(textBox1.Text, out b) == true)
//{
// b = double.Parse(textBox1.Text);
//}
//else
//{
// MessageBox.Show("Please enter the correct number!");
// textBox1.Text = "";
//}
}
//press*
private void button14_Click(object sender, EventArgs e)
{
c = true;
h = double.Parse(textBox1.Text);
switch (d)
{
case "+":
b = b + h;
break;
case "-":
b = b - h;
break;
case "*":
b = b * h;
break;
case "/":
b = b / h;
break;
case "%":
b = b % h;
break;
default:
b = h;
break;
}
d = "*";
//if (double.TryParse(textBox1.Text, out b) == true)
//{
// b = double.Parse(textBox1.Text);
//}
//else
//{
// MessageBox.Show("Please enter the correct number!");
// textBox1.Text = "";
//}
}
//press/
private void button12_Click(object sender, EventArgs e)
{
c = true;
h = double.Parse(textBox1.Text);
switch (d)
{
case "+":
b = b + h;
break;
case "-":
b = b - h;
break;
case "*":
b = b * h;
break;
case "/":
b = b / h;
break;
case "%":
b = b % h;
break;
default:
b = h;
break;
}
d = "/";
//if (double.TryParse(textBox1.Text, out b) == true)
//{
// b = double.Parse(textBox1.Text);
//}
//else
//{
// MessageBox.Show("Please enter the correct number!");
// textBox1.Text = "";
//}
}
//press %
private void button13_Click(object sender, EventArgs e)
{
c = true;
h = double.Parse(textBox1.Text);
switch (d)
{
case "+":
b = b + h;
break;
case "-":
b = b - h;
break;
case "*":
b = b * h;
break;
case "/":
b = b / h;
break;
case "%":
b = b % h;
break;
default:
b = h;
break;
}
d = "%";
//if (double.TryParse(textBox1.Text, out b) == true)
//{
// b = double.Parse(textBox1.Text);
//}
//else
//{
// MessageBox.Show("Please enter the correct number!");
// textBox1.Text = "";
//}
}
//press C
private void button15_Click(object sender, EventArgs e)
{
textBox1.Text = "";
}
//press=
private void button18_Click(object sender, EventArgs e)
{
if (double.TryParse(textBox1.Text, out h) == true)
{
h = double.Parse(textBox1.Text);
}
else
{
MessageBox.Show("Please enter the correct number!");
textBox1.Text = "";
}
switch (d)
{
case "+":
a = b + h;
break;
case "-":
a = b - h;
break;
case "*":
a = b * h;
break;
case "/":
a = b / h;
break;
case "%":
a = b % h;
break;
}
textBox1.Text = a + "";
d = "";
a = 0;
c = true;
}
}
}
Effect:
