Nullable Types in .NET

Introduction

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

Question: What is nullable type?

In simple terms "It provides flexibility for us to define null values to non-accepting datatypes".

Step 1: Create a new webform project

Step 2: The complete code of webform1.aspx looks like this:

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

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

</head>

<body>

<div>

<table>

<tr>

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

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

</td>

</tr>

<tr>

<asp:Button ID="Button1" runat="server" Text="Addition" Font-Names="Verdana" Width="213px"

BackColor="Orange" Font-Bold="True" OnClick="Button1_Click" />

</td>

</tr>

<tr>

<asp:Button ID="Button2" runat="server" Text="Substraction" Font-Names="Verdana"

Width="213px" BackColor="Orange" Font-Bold="True" OnClick="Button2_Click" />

</td>

</tr>

<tr>

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

Width="213px" BackColor="Orange" Font-Bold="True" OnClick="Button3_Click" />

</td>

</tr>

<tr>

<asp:Button ID="Button4" runat="server" Text="Division" Font-Names="Verdana" Width="213px"

BackColor="Orange" Font-Bold="True" OnClick="Button4_Click" />

</td>

</tr>

<tr>

<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 of 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 NullableTypesApp

{

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

{

protected void Page_Load(object sender, EventArgs e)

{

}

double? a = null;double? b = null;

protected void Button1_Click(object sender, EventArgs e)

{

//a = 10;

//b = 20;

if(a.HasValue == true && b.HasValue == true)

{

Label5.Text = "Addition Result is: " + (a + b);

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

}

else

{

Label5.Text = "Values are null";

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

}

protected void Button2_Click(object sender, EventArgs e)

{

//a = 20;

//b = 10;

if (a.HasValue && b.HasValue)

{

Label5.Text = "Substraction Result is: " + (a - b);Label5.ForeColor = System.Drawing.Color.Green;

}

else

{

Label5.Text = "Values are null";

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

}

protected void Button3_Click(object sender, EventArgs e)

{

//a = 10;//b = 20;

if (a.HasValue && b.HasValue)

{

Label5.Text = "Multiplication Result is: " + (a * b);

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

}

else

{

Label5.Text = "Values are null";

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

}

protected void Button4_Click(object sender, EventArgs e)

{

//a = 10;//b = 20;

if (a.HasValue && b.HasValue)

{

Label5.Text = "Division Result is: " + (a / b);

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

}

else

{

Label5.Text = "Values are null";

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

}

Step 4: The output of the application looks like this