C# Calculator App Using WinForms
Explore the functionality of our calculator application built with C# and Windows Forms. Copy this code!
MainForm class (MainForm.cs):
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 CalculatorApp
{
public partial class MainForm : Form
{
string operationSymbol;
double number;
bool buttonClicked = false;
public MainForm()
{
InitializeComponent();
}
private void btn0_Click(object sender, EventArgs e)
{
if (textBox1.Text != null && textBox1.Text == "0")
{
textBox1.Text = "0";
}
else
{
textBox1.Text = textBox1.Text + "0";
}
buttonClicked = true;
}
private void btn1_Click(object sender, EventArgs e)
{
if (textBox1.Text != null && textBox1.Text == "0")
{
textBox1.Text = "1";
}
else
{
textBox1.Text = textBox1.Text + "1";
}
buttonClicked = true;
}
private void btn2_Click(object sender, EventArgs e)
{
if (textBox1.Text != null && textBox1.Text == "0")
{
textBox1.Text = "2";
}
else
{
textBox1.Text = textBox1.Text + "2";
}
buttonClicked = true;
}
private void btn3_Click(object sender, EventArgs e)
{
if (textBox1.Text != null && textBox1.Text == "0")
{
textBox1.Text = "3";
}
else
{
textBox1.Text = textBox1.Text + "3";
}
buttonClicked = true;
}
private void btn4_Click(object sender, EventArgs e)
{
if (textBox1.Text != null && textBox1.Text == "0")
{
textBox1.Text = "4";
}
else
{
textBox1.Text = textBox1.Text + "4";
}
buttonClicked = true;
}
private void btn5_Click(object sender, EventArgs e)
{
if (textBox1.Text != null && textBox1.Text == "0")
{
textBox1.Text = "5";
}
else
{
textBox1.Text = textBox1.Text + "5";
}
buttonClicked = true;
}
private void btn6_Click(object sender, EventArgs e)
{
if (textBox1.Text != null && textBox1.Text == "0")
{
textBox1.Text = "6";
}
else
{
textBox1.Text = textBox1.Text + "6";
}
buttonClicked = true;
}
private void btn7_Click(object sender, EventArgs e)
{
if (textBox1.Text != null && textBox1.Text == "0")
{
textBox1.Text = "7";
}
else
{
textBox1.Text = textBox1.Text + "7";
}
buttonClicked = true;
}
private void btn8_Click(object sender, EventArgs e)
{
if (textBox1.Text != null && textBox1.Text == "0")
{
textBox1.Text = "8";
}
else
{
textBox1.Text = textBox1.Text + "8";
}
buttonClicked = true;
}
private void btn9_Click(object sender, EventArgs e)
{
if (textBox1.Text != null && textBox1.Text == "0")
{
textBox1.Text = "9";
}
else
{
textBox1.Text = textBox1.Text + "9";
}
buttonClicked = true;
}
private void btnPlus_Click(object sender, EventArgs e)
{
if (buttonClicked == true && textBox1.Text != "")
{
number = Convert.ToDouble(textBox1.Text);
textBox1.Text = "0";
operationSymbol = "+";
}
buttonClicked = false;
}
private void btnMinus_Click(object sender, EventArgs e)
{
if (buttonClicked == true && textBox1.Text != "")
{
number = Convert.ToDouble(textBox1.Text);
textBox1.Text = "0";
operationSymbol = "-";
}
buttonClicked = false;
}
private void btnMultiply_Click(object sender, EventArgs e)
{
if (buttonClicked == true && textBox1.Text != "")
{
number = Convert.ToDouble(textBox1.Text);
textBox1.Text = "0";
operationSymbol = "*";
}
buttonClicked = false;
}
private void btnDivide_Click(object sender, EventArgs e)
{
if (buttonClicked == true && textBox1.Text != "")
{
number = Convert.ToDouble(textBox1.Text);
textBox1.Text = "0";
operationSymbol = "/";
}
buttonClicked = false;
}
private void btnClear_Click(object sender, EventArgs e)
{
textBox1.Text = "";
}
private void btnEquals_Click(object sender, EventArgs e)
{
double secondNumber;
double result;
if (textBox1.Text != "")
{
secondNumber = Convert.ToDouble(textBox1.Text);
if (operationSymbol == "+")
{
result = (number + secondNumber);
textBox1.Text = Convert.ToString(result);
}
if (operationSymbol == "-")
{
result = (number - secondNumber);
textBox1.Text = Convert.ToString(result);
}
if (operationSymbol == "*")
{
result = (number * secondNumber);
textBox1.Text = Convert.ToString(result);
}
if (operationSymbol == "/")
{
if (secondNumber == 0)
{
textBox1.Text = "Error";
}
else
{
result = (number / secondNumber);
textBox1.Text = Convert.ToString(result);
number = result;
}
}
}
}
}
}
Program class (Program.cs):
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace CalculatorApp
{
internal static class Program
{
///
/// The main entry point for the application.
///
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new MainForm());
}
}
}
Partial class MainForm (MainForm.Designer.cs):
namespace CalculatorApp
{
partial class MainForm
{
private System.ComponentModel.IContainer components = null;
/// true if managed resources should be disposed; otherwise, false.
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}
#region Windows Form Designer generated code
///
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
///
private void InitializeComponent()
{
this.btn1 = new System.Windows.Forms.Button();
this.btn2 = new System.Windows.Forms.Button();
this.btn5 = new System.Windows.Forms.Button();
this.btn4 = new System.Windows.Forms.Button();
this.btn3 = new System.Windows.Forms.Button();
this.btn6 = new System.Windows.Forms.Button();
this.btn7 = new System.Windows.Forms.Button();
this.btn8 = new System.Windows.Forms.Button();
this.btn9 = new System.Windows.Forms.Button();
this.btn0 = new System.Windows.Forms.Button();
this.btnAdd = new System.Windows.Forms.Button();
this.btnSubtract = new System.Windows.Forms.Button();
this.btnMultiply = new System.Windows.Forms.Button();
this.btnDivide = new System.Windows.Forms.Button();
this.btnEquals = new System.Windows.Forms.Button();
this.btnClear = new System.Windows.Forms.Button();
this.textBox1 = new System.Windows.Forms.TextBox();
this.SuspendLayout();
//
// btn1
//
this.btn1.Location = new System.Drawing.Point(48, 139);
this.btn1.Name = "btn1";
this.btn1.Size = new System.Drawing.Size(56, 52);
this.btn1.TabIndex = 0;
this.btn1.Text = "1";
this.btn1.UseVisualStyleBackColor = true;
this.btn1.Click += new System.EventHandler(this.btn1_Click);
//
// btn2
//
this.btn2.Location = new System.Drawing.Point(110, 139);
this.btn2.Name = "btn2";
this.btn2.Size = new System.Drawing.Size(56, 52);
this.btn2.TabIndex = 1;
this.btn2.Text = "2";
this.btn2.UseVisualStyleBackColor = true;
this.btn2.Click += new System.EventHandler(this.btn2_Click);
//
// btn5
//
this.btn5.Location = new System.Drawing.Point(110, 197);
this.btn5.Name = "btn5";
this.btn5.Size = new System.Drawing.Size(56, 52);
this.btn5.TabIndex = 2;
this.btn5.Text = "5";
this.btn5.UseVisualStyleBackColor = true;
this.btn5.Click += new System.EventHandler(this.btn5_Click);
//
// btn4
//
this.btn4.Location = new System.Drawing.Point(48, 197);
this.btn4.Name = "btn4";
this.btn4.Size = new System.Drawing.Size(56, 52);
this.btn4.TabIndex = 3;
this.btn4.Text = "4";
this.btn4.UseVisualStyleBackColor = true;
this.btn4.Click += new System.EventHandler(this.btn4_Click);
//
// btn3
//
this.btn3.Location = new System.Drawing.Point(172, 139);
this.btn3.Name = "btn3";
this.btn3.Size = new System.Drawing.Size(56, 52);
this.btn3.TabIndex = 3;
this.btn3.Text = "3";
this.btn3.UseVisualStyleBackColor = true;
this.btn3.Click += new System.EventHandler(this.btn3_Click);
//
// btn6
//
this.btn6.Location = new System.Drawing.Point(172, 197);
this.btn6.Name = "btn6";
this.btn6.Size = new System.Drawing.Size(56, 52);
this.btn6.TabIndex = 4;
this.btn6.Text = "6";
this.btn6.UseVisualStyleBackColor = true;
this.btn6.Click += new System.EventHandler(this.btn6_Click);
//
// btn7
//
this.btn7.Location = new System.Drawing.Point(48, 255);
this.btn7.Name = "btn7";
this.btn7.Size = new System.Drawing.Size(56, 52);
this.btn7.TabIndex = 5;
this.btn7.Text = "7";
this.btn7.UseVisualStyleBackColor = true;
this.btn7.Click += new System.EventHandler(this.btn7_Click);
//
// btn8
//
this.btn8.Location = new System.Drawing.Point(110, 255);
this.btn8.Name = "btn8";
this.btn8.Size = new System.Drawing.Size(56, 52);
this.btn8.TabIndex = 6;
this.btn8.Text = "8";
this.btn8.UseVisualStyleBackColor = true;
this.btn8.Click += new System.EventHandler(this.btn8_Click);
//
// btn9
//
this.btn9.Location = new System.Drawing.Point(172, 255);
this.btn9.Name = "btn9";
this.btn9.Size = new System.Drawing.Size(56, 52);
this.btn9.TabIndex = 7;
this.btn9.Text = "9";
this.btn9.UseVisualStyleBackColor = true;
this.btn9.Click += new System.EventHandler(this.btn9_Click);
//
// btn0
//
this.btn0.Location = new System.Drawing.Point(110, 313);
this.btn0.Name = "btn0";
this.btn0.Size = new System.Drawing.Size(56, 52);
this.btn0.TabIndex = 8;
this.btn0.Text = "0";
this.btn0.UseVisualStyleBackColor = true;
this.btn0.Click += new System.EventHandler(this.btn0_Click);
//
// btnAdd
//
this.btnAdd.Location = new System.Drawing.Point(234, 139);
this.btnAdd.Name = "btnAdd";
this.btnAdd.Size = new System.Drawing.Size(56, 52);
this.btnAdd.TabIndex = 9;
this.btnAdd.Text = "+";
this.btnAdd.UseVisualStyleBackColor = true;
this.btnAdd.Click += new System.EventHandler(this.btnAdd_Click);
//
// btnSubtract
//
this.btnSubtract.Location = new System.Drawing.Point(234, 197);
this.btnSubtract.Name = "btnSubtract";
this.btnSubtract.Size = new System.Drawing.Size(56, 52);
this.btnSubtract.TabIndex = 10;
this.btnSubtract.Text = "-";
this.btnSubtract.UseVisualStyleBackColor = true;
this.btnSubtract.Click += new System.EventHandler(this.btnSubtract_Click);
//
// btnMultiply
//
this.btnMultiply.Location = new System.Drawing.Point(234, 255);
this.btnMultiply.Name = "btnMultiply";
this.btnMultiply.Size = new System.Drawing.Size(56, 52);
this.btnMultiply.TabIndex = 11;
this.btnMultiply.Text = "x";
this.btnMultiply.UseVisualStyleBackColor = true;
this.btnMultiply.Click += new System.EventHandler(this.btnMultiply_Click);
//
// btnDivide
//
this.btnDivide.Location = new System.Drawing.Point(234, 313);
this.btnDivide.Name = "btnDivide";
this.btnDivide.Size = new System.Drawing.Size(56, 52);
this.btnDivide.TabIndex = 12;
this.btnDivide.Text = "/";
this.btnDivide.UseVisualStyleBackColor = true;
this.btnDivide.Click += new System.EventHandler(this.btnDivide_Click);
//
// btnEquals
//
this.btnEquals.Location = new System.Drawing.Point(172, 313);
this.btnEquals.Name = "btnEquals";
this.btnEquals.Size = new System.Drawing.Size(56, 52);
this.btnEquals.TabIndex = 13;
this.btnEquals.Text = "=";
this.btnEquals.UseVisualStyleBackColor = true;
this.btnEquals.Click += new System.EventHandler(this.btnEquals_Click);
//
// btnClear
//
this.btnClear.Location = new System.Drawing.Point(48, 313);
this.btnClear.Name = "btnClear";
this.btnClear.Size = new System.Drawing.Size(56, 52);
this.btnClear.TabIndex = 14;
this.btnClear.Text = "C";
this.btnClear.UseVisualStyleBackColor = true;
this.btnClear.Click += new System.EventHandler(this.btnClear_Click);
//
// textBox1
//
this.textBox1.Location = new System.Drawing.Point(48, 107);
this.textBox1.Name = "textBox1";
this.textBox1.ReadOnly = true;
this.textBox1.Size = new System.Drawing.Size(242, 26);
this.textBox1.TabIndex = 15;
//
// MainForm
//
this.AutoScaleDimensions = new System.Drawing.SizeF(9F, 20F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(468, 450);
this.Controls.Add(this.textBox1);
this.Controls.Add(this.btnClear);
this.Controls.Add(this.btnEquals);
this.Controls.Add(this.btnDivide);
this.Controls.Add(this.btnMultiply);
this.Controls.Add(this.btnSubtract);
this.Controls.Add(this.btnAdd);
this.Controls.Add(this.btn0);
this.Controls.Add(this.btn9);
this.Controls.Add(this.btn8);
this.Controls.Add(this.btn7);
this.Controls.Add(this.btn6);
this.Controls.Add(this.btn3);
this.Controls.Add(this.btn4);
this.Controls.Add(this.btn5);
this.Controls.Add(this.btn2);
this.Controls.Add(this.btn1);
this.Name = "MainForm";
this.Text = "C# Calculator App";
this.ResumeLayout(false);
this.PerformLayout();
}
#endregion
private System.Windows.Forms.Button btn1;
private System.Windows.Forms.Button btn2;
private System.Windows.Forms.Button btn5;
private System.Windows.Forms.Button btn4;
private System.Windows.Forms.Button btn3;
private System.Windows.Forms.Button btn6;
private System.Windows.Forms.Button btn7;
private System.Windows.Forms.Button btn8;
private System.Windows.Forms.Button btn9;
private System.Windows.Forms.Button btn0;
private System.Windows.Forms.Button btnAdd;
private System.Windows.Forms.Button btnSubtract;
private System.Windows.Forms.Button btnMultiply;
private System.Windows.Forms.Button btnDivide;
private System.Windows.Forms.Button btnEquals;
private System.Windows.Forms.Button btnClear;
private System.Windows.Forms.TextBox textBox1;
}
}