Introduction
Today, in this blog let's play around with one of the interesting and most useful concept in C#.
Question: What is unchecked keyword?
In simple terms "It does exactly the reverse fashion of checked, it enables to suppress overflowing of data".
Step 1: Create a new WebForm project

Step 2: The complete code WebForm1.aspx looks like this
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="UnCheckedKeywordApp.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 3: 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;
namespace UnCheckedKeywordApp
{
public partial class WebForm1 : 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(TextBox2.Text))
{
Label5.Text = "Please Enter Some Values";
Label5.ForeColor = System.Drawing.Color.Red;
}
else
{
Label5.Text = "Addition Result is: " + (unchecked(int.Parse(TextBox1.Text) + int.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: " + (unchecked(int.Parse(TextBox1.Text) - int.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: " + (unchecked(int.Parse(TextBox1.Text) * int.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: " + (unchecked(int.Parse(TextBox1.Text) / int.Parse(TextBox2.Text)));
}
Label5.ForeColor = System.Drawing.Color.Green;
TextBox1.Text = string.Empty;
TextBox2.Text = string.Empty;
}
}
}
Step 4: The output of application looks like this


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