I guess you need something like the below code :-
Design page code :-
<![CDATA[<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>]]>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<table style="width: 100%;">
<tr>
<td><asp:label id="Label1" runat="server" text="Enter First Input" xmlns:asp="#unknown"></asp:label></td>
<td> <asp:textbox id="TextBox1" runat="server" xmlns:asp="#unknown"></asp:textbox></td>
</tr>
<tr>
<td><asp:label id="Label2" runat="server" text="Enter Second Input" xmlns:asp="#unknown"></asp:label></td>
<td> <asp:textbox id="TextBox2" runat="server" xmlns:asp="#unknown"></asp:textbox></td>
</tr>
<tr>
<td><asp:button id="Button1" runat="server" text="Button" onclick="Button1_Click" xmlns:asp="#unknown" /></td>
<td> </td>
</tr>
</table>
</div>
</form>
</body>
</html>
Code behind page code =
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
TextBox2.Text = scramble(TextBox1.Text);
}
private string scramble(string inputString)
{
string output = inputString;
return output;
}
}
Hope it will help you.