Let's Play Around With Composite Design Pattern

Vijay Prativadi
12y
5.1k
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Article

Introduction

Today, in this article let's play around with one of the interesting and most useful concepts of design patterns, which will be hosted in a web app.

Question: What is Composite Pattern?

In simple terms "Each independent object is led to lead an independent life, which creates a customized tree structure with many reference objects".

I think we are now good to go and implement this wonderful concept.

Step 1: The complete code of Default.aspx looks like this:

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

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

</head>

<body>

<div>

Composite Pattern - Design Patterns</h1>

<table>

<tr>

<td>

<asp:Label ID="Label1" runat="server" Text="Please Enter First Number" Font-Size="Small"

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

</td>

<td>

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

</td>

</tr>

<tr>

<td>

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

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

</td>

<td>

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

</td>

</tr>

<tr>

<asp:Button ID="Button1" runat="server" Text="Addition" Width="165px" Font-Names="Verdana"

BackColor="Orange" OnClick="Button1Click" />

</td>

</tr>

<tr>

<asp:Button ID="Button2" runat="server" Text="Subtraction" Width="165px" Font-Names="Verdana"

BackColor="Orange" OnClick="Button2Click" />

</td>

</tr>

<tr>

<asp:Button ID="Button3" runat="server" Text="Multiplication" Width="165px" Font-Names="Verdana"

BackColor="Orange" OnClick="Button3Click" />

</td>

</tr>

<tr>

<asp:Button ID="Button4" runat="server" Text="Division" Width="165px" Font-Names="Verdana"

BackColor="Orange" OnClick="Button4Click" />

</td>

</tr>

</table>

<table>

<tr>

<asp:Label ID="lblResult" runat="server" Font-Names="Verdana"></asp:Label>

</td>

</tr>

</table>

</center>

</div>

</form>

</body>

</html>

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

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace CompositeDesignPatternApp
{
public interface IArthmetic { double Arthmetic(double a, double b);}
}

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

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace CompositeDesignPatternApp

{

public class Addition : IArthmetic { public double Arthmetic(double a, double b) { return a + b; } }

}

Step 4: The complete code of Subtraction.cs looks like this:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace CompositeDesignPatternApp

{

public class Substraction : IArthmetic { public double Arthmetic(double a, double b) { return a - b; } }

}

Step 5: The complete code of Multiplication.cs looks like this:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace CompositeDesignPatternApp

{

public class Multiplication : IArthmetic { public double Arthmetic(double a, double b) { return a * b; } }

}

Step 6: The complete code of Division.cs looks like this:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace CompositeDesignPatternApp

{

public class Division : IArthmetic { public double Arthmetic(double a, double b) { return a / b; } }

}

Step 7: The complete code of Default.aspx.cs looks like this:

using System;

using System.Globalization;

namespace CompositeDesignPatternApp

{

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

{

protected void Page_Load(object sender, EventArgs e)

{

TextBox1.Focus();

}

protected void Button1Click(object sender, EventArgs e)

{

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

{

lblResult.Text = "Please Enter Some Values";

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

}

else

{

lblResult.Text = "Addition Result of <b>" + TextBox1.Text + "</b> and <b>" + TextBox2.Text + "</b> is <b>" +_objAddition.Arthmetic(Convert.ToDouble(TextBox1.Text), Convert.ToDouble(TextBox2.Text)).ToString(CultureInfo.InvariantCulture)+"</b>";

TextBox1.Text = "";TextBox2.Text = "";

}

protected void Button2Click(object sender, EventArgs e)

{

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

{

lblResult.Text = "Please Enter Some Values";

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

}

else

{

lblResult.Text = "Substraction Result of <b>" + TextBox1.Text + "</b> and <b>" + TextBox2.Text + "</b> is <b>" +_objSubstraction.Arthmetic(Convert.ToDouble(TextBox1.Text), Convert.ToDouble(TextBox2.Text)).ToString(CultureInfo.InvariantCulture) + "</b>";

TextBox1.Text = "";

TextBox2.Text = "";

}

protected void Button3Click(object sender, EventArgs e)

{

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

{

lblResult.Text = "Please Enter Some Values";

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

}

else

{

lblResult.Text = "Multiplication Result of <b>" + TextBox1.Text + "</b> and <b>" + TextBox2.Text + "</b> is <b>" +_objMultiplication.Arthmetic(Convert.ToDouble(TextBox1.Text), Convert.ToDouble(TextBox2.Text)).ToString(CultureInfo.InvariantCulture) + "</b>";TextBox1.Text = "";

TextBox2.Text = "";

}

protected void Button4Click(object sender, EventArgs e)

{

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

{

lblResult.Text = "Please Enter Some Values";

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

}

else

{

lblResult.Text = "Division Result of <b>" + TextBox1.Text + "</b> and <b>" + TextBox2.Text + "</b> is <b>" +_objDivision.Arthmetic(Convert.ToDouble(TextBox1.Text), Convert.ToDouble(TextBox2.Text)).ToString(CultureInfo.InvariantCulture) + "</b>";TextBox1.Text = "";TextBox2.Text = "";

}

#region Private Instance Variablesprivate readonly Addition _objAddition = new Addition();

private readonly Substraction _objSubstraction = new Substraction();

private readonly Multiplication _objMultiplication = new Multiplication();

private readonly Division _objDivision = new Division();#endregion}

}

Step 8: The output of the application looks like this: