Lambda Expressions in C#

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

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
  <center>
        <div>
            <table>
                <tr>
                    <td colspan="2" align="center">
                        <asp:Label ID="Label1" runat="server" Text="Arithmetic Operations with Lambda Expressions in C#"
                            Font-Bold="true" Font-Size="Large" Font-Names="Verdana" ForeColor="Maroon"></asp:Label>
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Label ID="Label6" runat="server" Text="Please Enter FirstNumber" Font-Size="Large" Font-Names="Verdana"
                            Font-Italic="true"></asp:Label>
                    </td>
                    <td>
                        <asp:TextBox ID="TextBox4" runat="server"></asp:TextBox>
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Label ID="Label2" runat="server" Text="Please Enter SecondNumber" Font-Size="Large"
                            Font-Names="Verdana" Font-Italic="true"></asp:Label>
                    </td>
                    <td>
                        <asp:TextBox ID="TextBox1" runat="server"></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"></asp:Label>
                    </td>
                </tr>
            </table>
        </div>
         </center>
    </form>
</body>
</html>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace LamdaExpressionApp
{
    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(TextBox4.Text) || string.IsNullOrEmpty(TextBox1.Text))
            {
                Label5.Text = "Please Enter Some Values";
                Label5.ForeColor = System.Drawing.Color.Red;

            }
            else
            {
                ArithmticDelegate objAdd = (x, y) => x + y;
                Label5.Text = "Addition Result is: " + objAdd.Invoke(double.Parse(TextBox4.Text), double.Parse(TextBox1.Text));
                Label5.ForeColor = System.Drawing.Color.Green;
                TextBox1.Text = string.Empty;
                TextBox4.Text = string.Empty;
            }
        }

        protected void Button2_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(TextBox4.Text) || string.IsNullOrEmpty(TextBox1.Text))
            {
                Label5.Text = "Please Enter Some Values";
                Label5.ForeColor = System.Drawing.Color.Red;

            }
            else
            {
                ArithmticDelegate objSub = (x, y) => x - y;
                Label5.Text = "Substraction Result is: " + objSub.Invoke(double.Parse(TextBox4.Text), double.Parse(TextBox1.Text));
                Label5.ForeColor = System.Drawing.Color.Green;
                TextBox1.Text = string.Empty;
                TextBox4.Text = string.Empty;
            }
        }

        protected void Button3_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(TextBox4.Text) || string.IsNullOrEmpty(TextBox1.Text))
            {
                Label5.Text = "Please Enter Some Values";
                Label5.ForeColor = System.Drawing.Color.Red;

            }
            else
            {
                ArithmticDelegate objMul = (x, y) => x * y;
                Label5.Text = "Multiplication Result is: " + objMul.Invoke(double.Parse(TextBox4.Text), double.Parse(TextBox1.Text));
                Label5.ForeColor = System.Drawing.Color.Green;
                TextBox1.Text = string.Empty;
                TextBox4.Text = string.Empty;
            }
        }

        protected void Button4_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(TextBox4.Text) || string.IsNullOrEmpty(TextBox1.Text))
            {
                Label5.Text = "Please Enter Some Values";
                Label5.ForeColor = System.Drawing.Color.Red;

            }
            else
            {
                ArithmticDelegate objDiv = (x, y) => x / y;
                Label5.Text = "Division Result is: " + objDiv.Invoke(double.Parse(TextBox4.Text), double.Parse(TextBox1.Text));
                Label5.ForeColor = System.Drawing.Color.Green;
                TextBox1.Text = string.Empty;
                TextBox4.Text = string.Empty;
            }
        }

        #region Public Members
        public delegate double ArithmticDelegate(double a, double b);
        #endregion
    }
}