How to create calculator in window application form c#

A simple calculator application in C# window form application. Here you will find easiest way to create a calculator in C# window form application.

Step 1.

Create a New window application form in Microsoft Visual Studio.

Step 2.

Design your Window Application Form like below form.

Step 3.

Now write the below coding in your application.

    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 WindowsFormsApplication1
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }

            string opr;
            double oparand1, oparand2, result;

            //button 1 coding
            private void button2_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 1;
            }

            //button 2 coding
            private void button3_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 2;
            }

            //button 3 coding
            private void button4_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 3;
            }

            //button 4 coding
            private void button5_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 4;
            }

            //button 5 coding
            private void button6_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 5;
            }

            //button 6 coding
            private void button7_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 6;
            }

            //button 7 coding
            private void button12_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 7;
            }

            //button 8 coding
            private void button11_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 8;
            }

            //button 9 coding
            private void button10_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 9;
            }

            //button 0 coding
            private void button9_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 0;
            }

            //dot button coding
            private void button18_Click(object sender, EventArgs e)
            {
                if (textBox1.Text.Contains("."))
                {
                    textBox1.Text = textBox1.Text;
                }
                else
                {
                    textBox1.Text = textBox1.Text + ".";
                }
            }

            private void button8_Click(object sender, EventArgs e)
            {
                textBox1.Text = textBox1.Text + 0+0;
            }

            //X button coding-clear code
            private void button1_Click(object sender, EventArgs e)
            {
                textBox1.Text = "";
            }

            //plus button coding
            private void button13_Click(object sender, EventArgs e)
            {
                oparand1 = Convert.ToDouble(textBox1.Text);
                opr = "+";
                textBox1.Clear();
            }

            //equal button coding
            private void button17_Click(object sender, EventArgs e)
            {
            oparand2 = Convert.ToDouble(textBox1.Text);
            switch (opr)
            {
            case "+": result = oparand1 + oparand2;
            textBox1.Text = Convert.ToString(result);
            break;

            case "-": 
            result = oparand1 - oparand2;
            textBox1.Text = Convert.ToString(result);
            break;
            
            case "*": 
            result = oparand1 * oparand2;
            textBox1.Text = Convert.ToString(result);
            break;
            
            case "/": 
            if (oparand2 == 0)
            {
            textBox1.Text = "0.0";
            break;
            }
            else
            {
            result = oparand1 / oparand2;
            textBox1.Text = Convert.ToString(result);
            break;
            }
            }
            }

            //multiply button coding
            private void button14_Click(object sender, EventArgs e)
            {
                oparand1 = Convert.ToDouble(textBox1.Text);
                opr = "*";
                textBox1.Clear();
            }

            //minus button coding
            private void button15_Click(object sender, EventArgs e)
            {
                oparand1 = Convert.ToDouble(textBox1.Text);
                opr = "-";
                textBox1.Clear();
            }

            //divide button coding
            private void button16_Click(object sender, EventArgs e)
            {
                oparand1 = Convert.ToDouble(textBox1.Text);
                opr = "/";
                textBox1.Clear();
            }        

        }
    }

Output: