Create and Consume DLL in .NET

 Introduction

 

Today, in this blog let's play around with one of the interesting and most useful concept in .NET.

Question: What is creating and consume DLL?

In simple terms "It enables to create DLL as components and use them across multiple projects".

Step 1: Create a new Class Library project

Image1.jpg

Step 2: The complete code of ArthmeticClass.cs looks like this:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace Arthmetic

{

    public class ArthmeticClass

    {

        public static double Add(double a, double b)

        {

            return a + b;

        }

        public static double Sub(double a, double b)

        {

            return a - b;

        }

        public static double Mul(double a, double b)

        {

            return a * b;

        }

        public static double Div(double a, double b)

        {

            return a / b;

        }

    }

}

Step 3: Create a new WebForm project

Image2.jpg

Step 4: Adding reference of DLL looks like this

Image3.jpg

Step 5: The complete code WebForm1.aspx looks like this:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="ArthmeticDLLApp.WebForm1" %>

 

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

<html xmlns="http://www.w3.org/1999/xhtml">

<head id="Head1" runat="server">

    <title></title>

</head>

<body>

    <form id="form1" runat="server">

    <center>

        <div>

            <table>

                <tr>

                    <td colspan="2">

                        <asp:Label ID="Label1" runat="server" Text="UnChecked Keyword in .NET" Font-Bold="true"

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

                    </td>

                </tr>

                <tr>

                    <td>

                        <asp:Label ID="Label3" runat="server" Text="Please Enter First Number" Font-Size="Large"

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

                    </td>

                    <td>

                        <asp:TextBox ID="TextBox1" runat="server" Width="120px"></asp:TextBox>

                    </td>

                </tr>

                <tr>

                    <td>

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

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

                    </td>

                    <td>

                        <asp:TextBox ID="TextBox2" runat="server" Width="120px"></asp:TextBox>

                    </td>

                </tr>

                <tr>

                    <td colspan="2" align="center">

                        <asp:Button ID="Button1" 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="Button2" 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="Button3" 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="Button4" 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="Label5" runat="server" Font-Bold="true" Font-Names="Verdana" ForeColor="Maroon"></asp:Label>

                    </td>

                </tr>

            </table>

        </div>

    </center>

    </form>

</body>

</html>

 

Step 6: The complete code 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;

using Arthmetic;

namespace ArthmeticDLLApp

{

    public partial class WebForm1 : System.Web.UI.Page

    {

        protected void Page_Load(object sender, EventArgs e)

        {

            TextBox1.Focus();

        }

        protected void Button1_Click(object sender, EventArgs e)

        {

            if (string.IsNullOrEmpty(TextBox1.Text) || string.IsNullOrEmpty(TextBox2.Text))

            {

                Label5.Text = "Please Enter Some Values";

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

            }

            else

            {

                Label5.Text = "Addition Result is: " + (ArthmeticClass.Add(double.Parse(TextBox1.Text), double.Parse(TextBox2.Text)));

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

                TextBox1.Text = string.Empty;

                TextBox2.Text = string.Empty;

            }

        }

        protected void Button2_Click(object sender, EventArgs e)

        {

            if (string.IsNullOrEmpty(TextBox1.Text) || string.IsNullOrEmpty(TextBox2.Text))

            {

                Label5.Text = "Please Enter Some Values";

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

            }

            else

            {

                Label5.Text = "Substraction Result is: " + (ArthmeticClass.Sub(double.Parse(TextBox1.Text), double.Parse(TextBox2.Text)));

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

                TextBox1.Text = string.Empty;

                TextBox2.Text = string.Empty;

            }

        }

        protected void Button3_Click(object sender, EventArgs e)

        {

            if (string.IsNullOrEmpty(TextBox1.Text) || string.IsNullOrEmpty(TextBox2.Text))

            {

                Label5.Text = "Please Enter Some Values";

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

            }

            else

            {

                Label5.Text = "Multiplication Result is: " + (ArthmeticClass.Mul(double.Parse(TextBox1.Text), double.Parse(TextBox2.Text)));

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

                TextBox1.Text = string.Empty;

                TextBox2.Text = string.Empty;

            }

        }

        protected void Button4_Click(object sender, EventArgs e)

        {

            if (string.IsNullOrEmpty(TextBox1.Text) || string.IsNullOrEmpty(TextBox2.Text))

            {

                Label5.Text = "Please Enter Some Values";

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

            }

            else

            {

                Label5.Text = "Division Result is: " + (ArthmeticClass.Div(double.Parse(TextBox1.Text), double.Parse(TextBox2.Text)));

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

                TextBox1.Text = string.Empty;

                TextBox2.Text = string.Empty;

            }

        }

    }

}

Step 7: The output of application looks like this

Image4.jpg
 

Step 8: The addition result output of application looks like this

Image5.jpg