Design Pattern : Singleton
Singleton pattern assures that only a single object will be created for any class and the same object will be used in the application.
Example (Adding Numbers ) :
Class file (here we will be writing the code for implementing singleton pattern)
public class CommonClass
{
private static CommonClass _instance;
protected CommonClass()
{
}
public static CommonClass Instance()
{
if (_instance == null) _instance = new CommonClass();
return _instance;
}
public int addNumber(int x, int y)
{
return (x + y);
}
}
ASPX :
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ShowAddNumber.aspx.cs" Inherits="ShowAddNumber" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
Enter Numbers to Add :<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><asp:TextBox ID="TextBox2" runat="server"></asp:TextBox><br />
<asp:Button ID="Button1" runat="server" Text="Submit" OnClick="Button1_Click" />
<br />
Result 1: <asp:Label ID="Label1" runat="server" Text=""></asp:Label><br />
Result 2: <asp:Label ID="Label2" runat="server" Text=""></asp:Label>
<br />
<asp:Label ID="lblMsg" runat="server" Text="Label"></asp:Label>
</div>
</form>
</body>
</html>
Singleton pattern assures that only a single object will be created for any class and the same object will be used in the application.
Example (Adding Numbers ) :
 |
| Solution Explorer |
Class file (here we will be writing the code for implementing singleton pattern)
public class CommonClass
{
private static CommonClass _instance;
protected CommonClass()
{
}
public static CommonClass Instance()
{
if (_instance == null) _instance = new CommonClass();
return _instance;
}
public int addNumber(int x, int y)
{
return (x + y);
}
}
ASPX :
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ShowAddNumber.aspx.cs" Inherits="ShowAddNumber" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
Enter Numbers to Add :<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><asp:TextBox ID="TextBox2" runat="server"></asp:TextBox><br />
<asp:Button ID="Button1" runat="server" Text="Submit" OnClick="Button1_Click" />
<br />
Result 1: <asp:Label ID="Label1" runat="server" Text=""></asp:Label><br />
Result 2: <asp:Label ID="Label2" runat="server" Text=""></asp:Label>
<br />
<asp:Label ID="lblMsg" runat="server" Text="Label"></asp:Label>
</div>
</form>
</body>
</html>
Codebehind:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class ShowAddNumber : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
public void Button1_Click(object sender, EventArgs e)
{
CommonClass s1 = CommonClass.Instance();
Label1.Text = s1.addNumber(int.Parse(TextBox1.Text), int.Parse(TextBox2.Text)).ToString();
CommonClass s2 = CommonClass.Instance();
Label2.Text = s2.addNumber(int.Parse(TextBox1.Text) + 5, int.Parse(TextBox2.Text) + 5).ToString();
if (s1 == s2)
{
lblMsg.Text = "Same Object Used";
}
}
}
Output :
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