Understanding Lambda Expressions in C#

Introduction

Today, in this article let's play around with one of the interesting and most useful concept in C#.

Question: What are lambda expressions?

In simple terms "It is an anonymous function which accepts some input parameters and performs an expected operation with lambda operator."

Step 1: Create a new webform project

Step 2: The complete code of webform1.aspx looks like this

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="LamdaExpressionApp.WebForm1" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head2" runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<center>
<div>
<table>
<tr>
<td colspan="2" align="center">
<asp:Label ID="Label3" runat="server" Text="Arithmetic Operations with Lambda Expressions in C#"
Font-Bold="true" Font-Size="Large" Font-Names="Verdana" ForeColor="Maroon"></asp:Label>
</td>
</tr>
<tr>
<td>
<asp:Label ID="Label4" runat="server" Text="Please Enter FirstNumber" Font-Size="Large"
Font-Names="Verdana" Font-Italic="true"></asp:Label>
</td>
<td>
<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
</td>
</tr>
<tr>
<td>
<asp:Label ID="Label7" runat="server" Text="Please Enter SecondNumber" Font-Size="Large"
Font-Names="Verdana" Font-Italic="true"></asp:Label>
</td>
<td>
<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
</td>
</tr>
<tr>
<td colspan="2" align="center">
<asp:Button ID="Button5" runat="server" Text="Addition" Font-Names="Verdana" Width="213px"
BackColor="Orange" Font-Bold="True" OnClick="Button1_Click" />
</td>
</tr>
<tr>
<td colspan="2" align="center">
<asp:Button ID="Button6" runat="server" Text="Substraction" Font-Names="Verdana"
Width="213px" BackColor="Orange" Font-Bold="True" OnClick="Button2_Click" />
</td>
</tr>
<tr>
<td colspan="2" align="center">
<asp:Button ID="Button7" runat="server" Text="Multiplication" Font-Names="Verdana"
Width="213px" BackColor="Orange" Font-Bold="True" OnClick="Button3_Click" />
</td>
</tr>
<tr>
<td colspan="2" align="center">
<asp:Button ID="Button8" runat="server" Text="Division" Font-Names="Verdana" Width="213px"
BackColor="Orange" Font-Bold="True" OnClick="Button4_Click" />
</td>
</tr>
<tr>
<td colspan="2" align="center">
<asp:Label ID="Label8" runat="server" Font-Bold="true" Font-Names="Verdana"></asp:Label>
</td>
</tr>
</table>
</div>
</center>
</form>
</body>
</html>

Step 3: The complete code of webform1.aspx.cs looks like this

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;namespace LamdaExpressionApp
{
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(TextBox4.Text) || string.IsNullOrEmpty(TextBox1.Text))
{
Label5.Text = "Please Enter Some Values";Label5.ForeColor = System.Drawing.Color.Red;
}
else
{
ArithmticDelegate objAdd = (x, y) => x + y;
Label5.Text = "Addition Result is: " + objAdd.Invoke(double.Parse(TextBox4.Text), double.Parse(TextBox1.Text));
Label5.ForeColor = System.Drawing.Color.Green;TextBox1.Text = string.Empty;
TextBox4.Text = string.Empty;
}
}
protected void Button2_Click(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(TextBox4.Text) || string.IsNullOrEmpty(TextBox1.Text))
{
Label5.Text = "Please Enter Some Values";
Label5.ForeColor = System.Drawing.Color.Red;
}
else
{
ArithmticDelegate objSub = (x, y) => x - y;
Label5.Text = "Substraction Result is: " + objSub.Invoke(double.Parse(TextBox4.Text), double.Parse(TextBox1.Text));
Label5.ForeColor = System.Drawing.Color.Green;TextBox1.Text = string.Empty;TextBox4.Text = string.Empty;
}
}
protected void Button3_Click(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(TextBox4.Text) || string.IsNullOrEmpty(TextBox1.Text))
{
Label5.Text = "Please Enter Some Values";Label5.ForeColor = System.Drawing.Color.Red;
}
else
{
ArithmticDelegate objMul = (x, y) => x * y;Label5.Text = "Multiplication Result is: " + objMul.Invoke(double.Parse(TextBox4.Text), double.Parse(TextBox1.Text));
Label5.ForeColor = System.Drawing.Color.Green;TextBox1.Text = string.Empty;TextBox4.Text = string.Empty;
}
}
protected void Button4_Click(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(TextBox4.Text) || string.IsNullOrEmpty(TextBox1.Text))
{
Label5.Text = "Please Enter Some Values";
Label5.ForeColor = System.Drawing.Color.Red;
}
else
{
ArithmticDelegate objDiv = (x, y) => x / y;
Label5.Text = "Division Result is: " + objDiv.Invoke(double.Parse(TextBox4.Text), double.Parse(TextBox1.Text));
Label5.ForeColor = System.Drawing.Color.Green;
TextBox1.Text = string.Empty;TextBox4.Text = string.Empty;
}
}
#region Public Memberspublic delegate double ArithmticDelegate(double a, double b);
#endregion
}
}

Step 4: The output of the application looks like this

Step 5: The addition operation output of the application looks like this

I hope this article is useful for you.