Play With Func Delegates

Introduction

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

Question: What is func delegates?

In simple terms "It is an instant startup powerful delegate. The usage of this is very light-weight whereby it just requires input and output return types as Func<in: type, out: result>".

Step 1: Create a new webform project

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

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="FuncDelegates._Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

</head>

<body>

<div>

<table>

<tr>

<asp:Label ID="Label1" runat="server" Text="Func Delegates" Font-Bold="true" Font-Size="Large"

Font-Names="Verdana" ForeColor="Maroon"></asp:Label>

</td>

</tr>

<tr>

<td>

<asp:Label ID="Label6" runat="server" Text="Please Enter FirstNumber" Font-Size="Large"

Font-Names="Verdana" Font-Italic="true"></asp:Label>

</td>

<td>

<asp:TextBox ID="TextBox4" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<td>

<asp:Label ID="Label2" runat="server" Text="Please Enter SecondNumber" Font-Size="Large"

Font-Names="Verdana" Font-Italic="true"></asp:Label>

</td>

<td>

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<asp:Button ID="Button1" runat="server" Text="Addition" Font-Names="Verdana" Width="213px"

BackColor="Orange" Font-Bold="True" OnClick="Button1_Click" />

</td>

</tr>

<tr>

<asp:Button ID="Button2" runat="server" Text="Substraction" Font-Names="Verdana"

Width="213px" BackColor="Orange" Font-Bold="True" OnClick="Button2_Click" />

</td>

</tr>

<tr>

<asp:Button ID="Button3" runat="server" Text="Multiplication" Font-Names="Verdana"

Width="213px" BackColor="Orange" Font-Bold="True" OnClick="Button3_Click" />

</td>

</tr>

<tr>

<asp:Button ID="Button4" runat="server" Text="Division" Font-Names="Verdana" Width="213px"

BackColor="Orange" Font-Bold="True" OnClick="Button4_Click" />

</td>

</tr>

<tr>

<asp:Label ID="Label5" runat="server" Font-Bold="true" Font-Names="Verdana" ForeColor="Maroon"></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 FuncDelegates

{

public partial class _Default : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

}

protected void Button1_Click(object sender, EventArgs e)

{

if (string.IsNullOrEmpty(TextBox1.Text) || string.IsNullOrEmpty(TextBox4.Text))

{

Label5.Text = "Please Enter Some Values";

Label5.ForeColor = System.Drawing.Color.Red;

}

else

{

Func<double, double, double> obj_Add = (r, q) => r + q; Label5.Text = "The Addition Result is " + obj_Add(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(TextBox1.Text) || string.IsNullOrEmpty(TextBox4.Text))

{

Label5.Text = "Please Enter Some Values";

Label5.ForeColor = System.Drawing.Color.Red;

}

else

{

Func<double, double, double> obj_Sub = (r, q) => r - q;

Label5.Text = "The Substraction Result is " + obj_Sub(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(TextBox1.Text) || string.IsNullOrEmpty(TextBox4.Text))

{

Label5.Text = "Please Enter Some Values";

Label5.ForeColor = System.Drawing.Color.Red;

}

else

{

Func<double, double, double> obj_Mul = (r, q) => r * q;

Label5.Text = "The Multiplication Result is " + obj_Mul(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(TextBox1.Text) || string.IsNullOrEmpty(TextBox4.Text))

{

Label5.Text = "Please Enter Some Values";

Label5.ForeColor = System.Drawing.Color.Red;

}

else

{

Func<double, double, double> obj_Div = (r, q) => r / q;

Label5.Text = "The Division Result is " + obj_Div(double.Parse(TextBox4.Text), double.Parse(TextBox1.Text));

Label5.ForeColor = System.Drawing.Color.Green; TextBox1.Text = string.Empty;

TextBox4.Text = string.Empty;

}

Step 4: The output of the application looks like this:

Step 4: The output of the addition operation result looks like this:

I hope this article is useful for you.