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">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<h1 style="text-align: center; font-family: Verdana; font-size: large; color: Maroon">
Composite Pattern - Design Patterns</h1>
<center>
<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>
<td colspan="2">
<asp:Button ID="Button1" runat="server" Text="Addition" Width="165px" Font-Names="Verdana"
BackColor="Orange" OnClick="Button1Click" />
</td>
</tr>
<tr>
<td colspan="2">
<asp:Button ID="Button2" runat="server" Text="Subtraction" Width="165px" Font-Names="Verdana"
BackColor="Orange" OnClick="Button2Click" />
</td>
</tr>
<tr>
<td colspan="2">
<asp:Button ID="Button3" runat="server" Text="Multiplication" Width="165px" Font-Names="Verdana"
BackColor="Orange" OnClick="Button3Click" />
</td>
</tr>
<tr>
<td colspan="2">
<asp:Button ID="Button4" runat="server" Text="Division" Width="165px" Font-Names="Verdana"
BackColor="Orange" OnClick="Button4Click" />
</td>
</tr>
</table>
<table>
<tr>
<td colspan="2">
<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:
![Output1.png]()
Step 9: The output of the nothing entered application looks like this:
![Output2.png]()
Step 10: The output of the addition operation application looks like this:
![Output3.png]()
Step 11: The output of the multiplication operation application looks like this:
![Output4.png]()
I hope this article is useful for you.